17 files changed, 534 insertions, 212 deletions

diff --git a/src/core/ext/filters/client_channel/http_connect_handshaker.c b/src/core/ext/filters/client_channel/http_connect_handshaker.c
index 0952dc6d4e..418bb41ef6 100644
--- a/src/core/ext/filters/client_channel/http_connect_handshaker.c
+++ b/src/core/ext/filters/client_channel/http_connect_handshaker.c
@@ -124,7 +124,7 @@ static void handshake_failed_locked(grpc_exec_ctx* exec_ctx,
 // Callback invoked when finished writing HTTP CONNECT request.
 static void on_write_done(grpc_exec_ctx* exec_ctx, void* arg,
                           grpc_error* error) {
-  http_connect_handshaker* handshaker = arg;
+  http_connect_handshaker* handshaker = (http_connect_handshaker*)arg;
   gpr_mu_lock(&handshaker->mu);
   if (error != GRPC_ERROR_NONE || handshaker->shutdown) {
     // If the write failed or we're shutting down, clean up and invoke the
@@ -145,7 +145,7 @@ static void on_write_done(grpc_exec_ctx* exec_ctx, void* arg,
 // Callback invoked for reading HTTP CONNECT response.
 static void on_read_done(grpc_exec_ctx* exec_ctx, void* arg,
                          grpc_error* error) {
-  http_connect_handshaker* handshaker = arg;
+  http_connect_handshaker* handshaker = (http_connect_handshaker*)arg;
   gpr_mu_lock(&handshaker->mu);
   if (error != GRPC_ERROR_NONE || handshaker->shutdown) {
     // If the read failed or we're shutting down, clean up and invoke the
@@ -281,7 +281,8 @@ static void http_connect_handshaker_do_handshake(
     GPR_ASSERT(arg->type == GRPC_ARG_STRING);
     gpr_string_split(arg->value.string, "\n", &header_strings,
                      &num_header_strings);
-    headers = gpr_malloc(sizeof(grpc_http_header) * num_header_strings);
+    headers = (grpc_http_header*)gpr_malloc(sizeof(grpc_http_header) *
+                                            num_header_strings);
     for (size_t i = 0; i < num_header_strings; ++i) {
       char* sep = strchr(header_strings[i], ':');
       if (sep == NULL) {
@@ -308,7 +309,7 @@ static void http_connect_handshaker_do_handshake(
   grpc_httpcli_request request;
   memset(&request, 0, sizeof(request));
   request.host = server_name;
-  request.http.method = "CONNECT";
+  request.http.method = (char*)"CONNECT";
   request.http.path = server_name;
   request.http.hdrs = headers;
   request.http.hdr_count = num_headers;
@@ -333,7 +334,8 @@ static const grpc_handshaker_vtable http_connect_handshaker_vtable = {
     http_connect_handshaker_do_handshake};
 
 static grpc_handshaker* grpc_http_connect_handshaker_create() {
-  http_connect_handshaker* handshaker = gpr_malloc(sizeof(*handshaker));
+  http_connect_handshaker* handshaker =
+      (http_connect_handshaker*)gpr_malloc(sizeof(*handshaker));
   memset(handshaker, 0, sizeof(*handshaker));
   grpc_handshaker_init(&http_connect_handshaker_vtable, &handshaker->base);
   gpr_mu_init(&handshaker->mu);
diff --git a/src/core/ext/transport/chttp2/transport/chttp2_transport.c b/src/core/ext/transport/chttp2/transport/chttp2_transport.c
index 7541bd5c92..9d9e4ea2ba 100644
--- a/src/core/ext/transport/chttp2/transport/chttp2_transport.c
+++ b/src/core/ext/transport/chttp2/transport/chttp2_transport.c
@@ -83,8 +83,6 @@ grpc_tracer_flag grpc_trace_chttp2_refcount =
     GRPC_TRACER_INITIALIZER(false, "chttp2_refcount");
 #endif
 
-static const grpc_transport_vtable vtable;
-
 /* forward declarations of various callbacks that we'll build closures around */
 static void write_action_begin_locked(grpc_exec_ctx *exec_ctx, void *t,
                                       grpc_error *error);
@@ -247,6 +245,8 @@ void grpc_chttp2_unref_transport(grpc_exec_ctx *exec_ctx,
 void grpc_chttp2_ref_transport(grpc_chttp2_transport *t) { gpr_ref(&t->refs); }
 #endif
 
+static const grpc_transport_vtable *get_vtable(void);
+
 static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
                            const grpc_channel_args *channel_args,
                            grpc_endpoint *ep, bool is_client) {
@@ -256,7 +256,7 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   GPR_ASSERT(strlen(GRPC_CHTTP2_CLIENT_CONNECT_STRING) ==
              GRPC_CHTTP2_CLIENT_CONNECT_STRLEN);
 
-  t->base.vtable = &vtable;
+  t->base.vtable = get_vtable();
   t->ep = ep;
   /* one ref is for destroy */
   gpr_ref_init(&t->refs, 1);
@@ -556,11 +556,6 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
     }
   }
 
-  GRPC_CLOSURE_INIT(&t->write_action, write_action, t,
-                    t->opt_target == GRPC_CHTTP2_OPTIMIZE_FOR_THROUGHPUT
-                        ? grpc_executor_scheduler
-                        : grpc_schedule_on_exec_ctx);
-
   t->ping_state.pings_before_data_required =
       t->ping_policy.max_pings_without_data;
   t->ping_state.is_delayed_ping_timer_set = false;
@@ -588,7 +583,7 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
 
 static void destroy_transport_locked(grpc_exec_ctx *exec_ctx, void *tp,
                                      grpc_error *error) {
-  grpc_chttp2_transport *t = tp;
+  grpc_chttp2_transport *t = (grpc_chttp2_transport *)tp;
   t->destroying = 1;
   close_transport_locked(
       exec_ctx, t,
@@ -714,7 +709,7 @@ static int init_stream(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
 
 static void destroy_stream_locked(grpc_exec_ctx *exec_ctx, void *sp,
                                   grpc_error *error) {
-  grpc_chttp2_stream *s = sp;
+  grpc_chttp2_stream *s = (grpc_chttp2_stream *)sp;
   grpc_chttp2_transport *t = s->t;
 
   GPR_TIMER_BEGIN("destroy_stream", 0);
@@ -798,7 +793,7 @@ static void destroy_stream(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
 
 grpc_chttp2_stream *grpc_chttp2_parsing_lookup_stream(grpc_chttp2_transport *t,
                                                       uint32_t id) {
-  return grpc_chttp2_stream_map_find(&t->stream_map, id);
+  return (grpc_chttp2_stream *)grpc_chttp2_stream_map_find(&t->stream_map, id);
 }
 
 grpc_chttp2_stream *grpc_chttp2_parsing_accept_stream(grpc_exec_ctx *exec_ctx,
@@ -857,6 +852,7 @@ void grpc_chttp2_initiate_write(grpc_exec_ctx *exec_ctx,
   switch (t->write_state) {
     case GRPC_CHTTP2_WRITE_STATE_IDLE:
       set_write_state(exec_ctx, t, GRPC_CHTTP2_WRITE_STATE_WRITING, reason);
+      t->is_first_write_in_batch = true;
       GRPC_CHTTP2_REF_TRANSPORT(t, "writing");
       GRPC_CLOSURE_SCHED(
           exec_ctx,
@@ -875,52 +871,91 @@ void grpc_chttp2_initiate_write(grpc_exec_ctx *exec_ctx,
   GPR_TIMER_END("grpc_chttp2_initiate_write", 0);
 }
 
-void grpc_chttp2_become_writable(
-    grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t, grpc_chttp2_stream *s,
-    grpc_chttp2_stream_write_type stream_write_type, const char *reason) {
+void grpc_chttp2_become_writable(grpc_exec_ctx *exec_ctx,
+                                 grpc_chttp2_transport *t,
+                                 grpc_chttp2_stream *s,
+                                 bool also_initiate_write, const char *reason) {
   if (!t->closed && grpc_chttp2_list_add_writable_stream(t, s)) {
     GRPC_CHTTP2_STREAM_REF(s, "chttp2_writing:become");
   }
-  switch (stream_write_type) {
-    case GRPC_CHTTP2_STREAM_WRITE_PIGGYBACK:
-      break;
-    case GRPC_CHTTP2_STREAM_WRITE_INITIATE_COVERED:
-      grpc_chttp2_initiate_write(exec_ctx, t, reason);
-      break;
-    case GRPC_CHTTP2_STREAM_WRITE_INITIATE_UNCOVERED:
-      grpc_chttp2_initiate_write(exec_ctx, t, reason);
-      break;
+  if (also_initiate_write) {
+    grpc_chttp2_initiate_write(exec_ctx, t, reason);
+  }
+}
+
+static grpc_closure_scheduler *write_scheduler(grpc_chttp2_transport *t,
+                                               bool early_results_scheduled,
+                                               bool partial_write) {
+  /* if it's not the first write in a batch, always offload to the executor:
+     we'll probably end up queuing against the kernel anyway, so we'll likely
+     get better latency overall if we switch writing work elsewhere and continue
+     with application work above */
+  if (!t->is_first_write_in_batch) {
+    return grpc_executor_scheduler(GRPC_EXECUTOR_SHORT);
   }
+  /* equivalently, if it's a partial write, we *know* we're going to be taking a
+     thread jump to write it because of the above, may as well do so
+     immediately */
+  if (partial_write) {
+    return grpc_executor_scheduler(GRPC_EXECUTOR_SHORT);
+  }
+  switch (t->opt_target) {
+    case GRPC_CHTTP2_OPTIMIZE_FOR_THROUGHPUT:
+      /* executor gives us the largest probability of being able to batch a
+       * write with others on this transport */
+      return grpc_executor_scheduler(GRPC_EXECUTOR_SHORT);
+    case GRPC_CHTTP2_OPTIMIZE_FOR_LATENCY:
+      return grpc_schedule_on_exec_ctx;
+  }
+  GPR_UNREACHABLE_CODE(return NULL);
+}
+
+#define WRITE_STATE_TUPLE_TO_INT(p, i) (2 * (int)(p) + (int)(i))
+static const char *begin_writing_desc(bool partial, bool inlined) {
+  switch (WRITE_STATE_TUPLE_TO_INT(partial, inlined)) {
+    case WRITE_STATE_TUPLE_TO_INT(false, false):
+      return "begin write in background";
+    case WRITE_STATE_TUPLE_TO_INT(false, true):
+      return "begin write in current thread";
+    case WRITE_STATE_TUPLE_TO_INT(true, false):
+      return "begin partial write in background";
+    case WRITE_STATE_TUPLE_TO_INT(true, true):
+      return "begin partial write in current thread";
+  }
+  GPR_UNREACHABLE_CODE(return "bad state tuple");
 }
 
 static void write_action_begin_locked(grpc_exec_ctx *exec_ctx, void *gt,
                                       grpc_error *error_ignored) {
   GPR_TIMER_BEGIN("write_action_begin_locked", 0);
-  grpc_chttp2_transport *t = gt;
+  grpc_chttp2_transport *t = (grpc_chttp2_transport *)gt;
   GPR_ASSERT(t->write_state != GRPC_CHTTP2_WRITE_STATE_IDLE);
-  switch (t->closed ? GRPC_CHTTP2_NOTHING_TO_WRITE
-                    : grpc_chttp2_begin_write(exec_ctx, t)) {
-    case GRPC_CHTTP2_NOTHING_TO_WRITE:
-      set_write_state(exec_ctx, t, GRPC_CHTTP2_WRITE_STATE_IDLE,
-                      "begin writing nothing");
-      GRPC_CHTTP2_UNREF_TRANSPORT(exec_ctx, t, "writing");
-      break;
-    case GRPC_CHTTP2_PARTIAL_WRITE:
-      set_write_state(exec_ctx, t, GRPC_CHTTP2_WRITE_STATE_WRITING_WITH_MORE,
-                      "begin writing partial");
-      GRPC_CLOSURE_SCHED(exec_ctx, &t->write_action, GRPC_ERROR_NONE);
-      break;
-    case GRPC_CHTTP2_FULL_WRITE:
-      set_write_state(exec_ctx, t, GRPC_CHTTP2_WRITE_STATE_WRITING,
-                      "begin writing");
-      GRPC_CLOSURE_SCHED(exec_ctx, &t->write_action, GRPC_ERROR_NONE);
-      break;
+  grpc_chttp2_begin_write_result r;
+  if (t->closed) {
+    r.writing = false;
+  } else {
+    r = grpc_chttp2_begin_write(exec_ctx, t);
+  }
+  if (r.writing) {
+    grpc_closure_scheduler *scheduler =
+        write_scheduler(t, r.early_results_scheduled, r.partial);
+    set_write_state(
+        exec_ctx, t, r.partial ? GRPC_CHTTP2_WRITE_STATE_WRITING_WITH_MORE
+                               : GRPC_CHTTP2_WRITE_STATE_WRITING,
+        begin_writing_desc(r.partial, scheduler == grpc_schedule_on_exec_ctx));
+    GRPC_CLOSURE_SCHED(exec_ctx, GRPC_CLOSURE_INIT(&t->write_action,
+                                                   write_action, t, scheduler),
+                       GRPC_ERROR_NONE);
+  } else {
+    set_write_state(exec_ctx, t, GRPC_CHTTP2_WRITE_STATE_IDLE,
+                    "begin writing nothing");
+    GRPC_CHTTP2_UNREF_TRANSPORT(exec_ctx, t, "writing");
   }
   GPR_TIMER_END("write_action_begin_locked", 0);
 }
 
 static void write_action(grpc_exec_ctx *exec_ctx, void *gt, grpc_error *error) {
-  grpc_chttp2_transport *t = gt;
+  grpc_chttp2_transport *t = (grpc_chttp2_transport *)gt;
   GPR_TIMER_BEGIN("write_action", 0);
   grpc_endpoint_write(
       exec_ctx, t->ep, &t->outbuf,
@@ -932,7 +967,7 @@ static void write_action(grpc_exec_ctx *exec_ctx, void *gt, grpc_error *error) {
 static void write_action_end_locked(grpc_exec_ctx *exec_ctx, void *tp,
                                     grpc_error *error) {
   GPR_TIMER_BEGIN("terminate_writing_with_lock", 0);
-  grpc_chttp2_transport *t = tp;
+  grpc_chttp2_transport *t = (grpc_chttp2_transport *)tp;
 
   if (error != GRPC_ERROR_NONE) {
     close_transport_locked(exec_ctx, t, GRPC_ERROR_REF(error));
@@ -957,7 +992,8 @@ static void write_action_end_locked(grpc_exec_ctx *exec_ctx, void *tp,
     case GRPC_CHTTP2_WRITE_STATE_WRITING_WITH_MORE:
       GPR_TIMER_MARK("state=writing_stale_no_poller", 0);
       set_write_state(exec_ctx, t, GRPC_CHTTP2_WRITE_STATE_WRITING,
-                      "continue writing [!covered]");
+                      "continue writing");
+      t->is_first_write_in_batch = false;
       GRPC_CHTTP2_REF_TRANSPORT(t, "writing");
       GRPC_CLOSURE_RUN(
           exec_ctx,
@@ -1059,9 +1095,7 @@ static void maybe_start_some_streams(grpc_exec_ctx *exec_ctx,
 
     grpc_chttp2_stream_map_add(&t->stream_map, s->id, s);
     post_destructive_reclaimer(exec_ctx, t);
-    grpc_chttp2_become_writable(exec_ctx, t, s,
-                                GRPC_CHTTP2_STREAM_WRITE_INITIATE_COVERED,
-                                "new_stream");
+    grpc_chttp2_become_writable(exec_ctx, t, s, true, "new_stream");
   }
   /* cancel out streams that will never be started */
   while (t->next_stream_id >= MAX_CLIENT_STREAM_ID &&
@@ -1110,12 +1144,14 @@ void grpc_chttp2_complete_closure_step(grpc_exec_ctx *exec_ctx,
   closure->next_data.scratch -= CLOSURE_BARRIER_FIRST_REF_BIT;
   if (GRPC_TRACER_ON(grpc_http_trace)) {
     const char *errstr = grpc_error_string(error);
-    gpr_log(GPR_DEBUG,
-            "complete_closure_step: %p refs=%d flags=0x%04x desc=%s err=%s",
-            closure,
-            (int)(closure->next_data.scratch / CLOSURE_BARRIER_FIRST_REF_BIT),
-            (int)(closure->next_data.scratch % CLOSURE_BARRIER_FIRST_REF_BIT),
-            desc, errstr);
+    gpr_log(
+        GPR_DEBUG,
+        "complete_closure_step: t=%p %p refs=%d flags=0x%04x desc=%s err=%s "
+        "write_state=%s",
+        t, closure,
+        (int)(closure->next_data.scratch / CLOSURE_BARRIER_FIRST_REF_BIT),
+        (int)(closure->next_data.scratch % CLOSURE_BARRIER_FIRST_REF_BIT), desc,
+        errstr, write_state_name(t->write_state));
   }
   if (error != GRPC_ERROR_NONE) {
     if (closure->error_data.error == GRPC_ERROR_NONE) {
@@ -1156,9 +1192,7 @@ static void maybe_become_writable_due_to_send_msg(grpc_exec_ctx *exec_ctx,
                                                   grpc_chttp2_stream *s) {
   if (s->id != 0 && (!s->write_buffering ||
                      s->flow_controlled_buffer.length > t->write_buffer_size)) {
-    grpc_chttp2_become_writable(exec_ctx, t, s,
-                                GRPC_CHTTP2_STREAM_WRITE_INITIATE_COVERED,
-                                "op.send_message");
+    grpc_chttp2_become_writable(exec_ctx, t, s, true, "op.send_message");
   }
 }
 
@@ -1190,15 +1224,19 @@ static void continue_fetching_send_locked(grpc_exec_ctx *exec_ctx,
       } else {
         grpc_chttp2_write_cb *cb = t->write_cb_pool;
         if (cb == NULL) {
-          cb = gpr_malloc(sizeof(*cb));
+          cb = (grpc_chttp2_write_cb *)gpr_malloc(sizeof(*cb));
         } else {
           t->write_cb_pool = cb->next;
         }
         cb->call_at_byte = notify_offset;
         cb->closure = s->fetching_send_message_finished;
         s->fetching_send_message_finished = NULL;
-        cb->next = s->on_write_finished_cbs;
-        s->on_write_finished_cbs = cb;
+        grpc_chttp2_write_cb **list =
+            s->fetching_send_message->flags & GRPC_WRITE_THROUGH
+                ? &s->on_write_finished_cbs
+                : &s->on_flow_controlled_cbs;
+        cb->next = *list;
+        *list = cb;
       }
       s->fetching_send_message = NULL;
       return; /* early out */
@@ -1218,7 +1256,7 @@ static void continue_fetching_send_locked(grpc_exec_ctx *exec_ctx,
 
 static void complete_fetch_locked(grpc_exec_ctx *exec_ctx, void *gs,
                                   grpc_error *error) {
-  grpc_chttp2_stream *s = gs;
+  grpc_chttp2_stream *s = (grpc_chttp2_stream *)gs;
   grpc_chttp2_transport *t = s->t;
   if (error == GRPC_ERROR_NONE) {
     error = grpc_byte_stream_pull(exec_ctx, s->fetching_send_message,
@@ -1253,8 +1291,9 @@ static void perform_stream_op_locked(grpc_exec_ctx *exec_ctx, void *stream_op,
                                      grpc_error *error_ignored) {
   GPR_TIMER_BEGIN("perform_stream_op_locked", 0);
 
-  grpc_transport_stream_op_batch *op = stream_op;
-  grpc_chttp2_stream *s = op->handler_private.extra_arg;
+  grpc_transport_stream_op_batch *op =
+      (grpc_transport_stream_op_batch *)stream_op;
+  grpc_chttp2_stream *s = (grpc_chttp2_stream *)op->handler_private.extra_arg;
   grpc_transport_stream_op_batch_payload *op_payload = op->payload;
   grpc_chttp2_transport *t = s->t;
 
@@ -1350,14 +1389,13 @@ static void perform_stream_op_locked(grpc_exec_ctx *exec_ctx, void *stream_op,
           }
         } else {
           GPR_ASSERT(s->id != 0);
-          grpc_chttp2_stream_write_type write_type =
-              GRPC_CHTTP2_STREAM_WRITE_INITIATE_COVERED;
+          bool initiate_write = true;
           if (op->send_message &&
               (op->payload->send_message.send_message->flags &
                GRPC_WRITE_BUFFER_HINT)) {
-            write_type = GRPC_CHTTP2_STREAM_WRITE_PIGGYBACK;
+            initiate_write = false;
           }
-          grpc_chttp2_become_writable(exec_ctx, t, s, write_type,
+          grpc_chttp2_become_writable(exec_ctx, t, s, initiate_write,
                                       "op.send_initial_metadata");
         }
       } else {
@@ -1451,8 +1489,7 @@ static void perform_stream_op_locked(grpc_exec_ctx *exec_ctx, void *stream_op,
       } else if (s->id != 0) {
         /* TODO(ctiller): check if there's flow control for any outstanding
            bytes before going writable */
-        grpc_chttp2_become_writable(exec_ctx, t, s,
-                                    GRPC_CHTTP2_STREAM_WRITE_INITIATE_COVERED,
+        grpc_chttp2_become_writable(exec_ctx, t, s, true,
                                     "op.send_trailing_metadata");
       }
     }
@@ -1572,7 +1609,7 @@ static void send_ping_locked(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
 
 static void retry_initiate_ping_locked(grpc_exec_ctx *exec_ctx, void *tp,
                                        grpc_error *error) {
-  grpc_chttp2_transport *t = tp;
+  grpc_chttp2_transport *t = (grpc_chttp2_transport *)tp;
   t->ping_state.is_delayed_ping_timer_set = false;
   grpc_chttp2_initiate_write(exec_ctx, t, "retry_send_ping");
 }
@@ -1624,8 +1661,9 @@ void grpc_chttp2_add_ping_strike(grpc_exec_ctx *exec_ctx,
 static void perform_transport_op_locked(grpc_exec_ctx *exec_ctx,
                                         void *stream_op,
                                         grpc_error *error_ignored) {
-  grpc_transport_op *op = stream_op;
-  grpc_chttp2_transport *t = op->handler_private.extra_arg;
+  grpc_transport_op *op = (grpc_transport_op *)stream_op;
+  grpc_chttp2_transport *t =
+      (grpc_chttp2_transport *)op->handler_private.extra_arg;
   grpc_error *close_transport = op->disconnect_with_error;
 
   if (op->goaway_error) {
@@ -1838,7 +1876,8 @@ void grpc_chttp2_maybe_complete_recv_trailing_metadata(grpc_exec_ctx *exec_ctx,
 
 static void remove_stream(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
                           uint32_t id, grpc_error *error) {
-  grpc_chttp2_stream *s = grpc_chttp2_stream_map_delete(&t->stream_map, id);
+  grpc_chttp2_stream *s =
+      (grpc_chttp2_stream *)grpc_chttp2_stream_map_delete(&t->stream_map, id);
   GPR_ASSERT(s);
   if (t->incoming_stream == s) {
     t->incoming_stream = NULL;
@@ -1969,6 +2008,21 @@ static grpc_error *removal_error(grpc_error *extra_error, grpc_chttp2_stream *s,
   return error;
 }
 
+static void flush_write_list(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
+                             grpc_chttp2_stream *s, grpc_chttp2_write_cb **list,
+                             grpc_error *error) {
+  while (*list) {
+    grpc_chttp2_write_cb *cb = *list;
+    *list = cb->next;
+    grpc_chttp2_complete_closure_step(exec_ctx, t, s, &cb->closure,
+                                      GRPC_ERROR_REF(error),
+                                      "on_write_finished_cb");
+    cb->next = t->write_cb_pool;
+    t->write_cb_pool = cb;
+  }
+  GRPC_ERROR_UNREF(error);
+}
+
 void grpc_chttp2_fail_pending_writes(grpc_exec_ctx *exec_ctx,
                                      grpc_chttp2_transport *t,
                                      grpc_chttp2_stream *s, grpc_error *error) {
@@ -1988,16 +2042,9 @@ void grpc_chttp2_fail_pending_writes(grpc_exec_ctx *exec_ctx,
   grpc_chttp2_complete_closure_step(
       exec_ctx, t, s, &s->fetching_send_message_finished, GRPC_ERROR_REF(error),
       "fetching_send_message_finished");
-  while (s->on_write_finished_cbs) {
-    grpc_chttp2_write_cb *cb = s->on_write_finished_cbs;
-    s->on_write_finished_cbs = cb->next;
-    grpc_chttp2_complete_closure_step(exec_ctx, t, s, &cb->closure,
-                                      GRPC_ERROR_REF(error),
-                                      "on_write_finished_cb");
-    cb->next = t->write_cb_pool;
-    t->write_cb_pool = cb;
-  }
-  GRPC_ERROR_UNREF(error);
+  flush_write_list(exec_ctx, t, s, &s->on_write_finished_cbs,
+                   GRPC_ERROR_REF(error));
+  flush_write_list(exec_ctx, t, s, &s->on_flow_controlled_cbs, error);
 }
 
 void grpc_chttp2_mark_stream_closed(grpc_exec_ctx *exec_ctx,
@@ -2241,13 +2288,11 @@ void grpc_chttp2_act_on_flowctl_action(grpc_exec_ctx *exec_ctx,
     case GRPC_CHTTP2_FLOWCTL_NO_ACTION_NEEDED:
       break;
     case GRPC_CHTTP2_FLOWCTL_UPDATE_IMMEDIATELY:
-      grpc_chttp2_become_writable(exec_ctx, t, s,
-                                  GRPC_CHTTP2_STREAM_WRITE_INITIATE_COVERED,
+      grpc_chttp2_become_writable(exec_ctx, t, s, true,
                                   "immediate stream flowctl");
       break;
     case GRPC_CHTTP2_FLOWCTL_QUEUE_UPDATE:
-      grpc_chttp2_become_writable(exec_ctx, t, s,
-                                  GRPC_CHTTP2_STREAM_WRITE_PIGGYBACK,
+      grpc_chttp2_become_writable(exec_ctx, t, s, false,
                                   "queue stream flowctl");
       break;
   }
@@ -2360,9 +2405,7 @@ static void read_action_locked(grpc_exec_ctx *exec_ctx, void *tp,
       if (t->flow_control.initial_window_update > 0) {
         grpc_chttp2_stream *s;
         while (grpc_chttp2_list_pop_stalled_by_stream(t, &s)) {
-          grpc_chttp2_become_writable(
-              exec_ctx, t, s, GRPC_CHTTP2_STREAM_WRITE_INITIATE_UNCOVERED,
-              "unstalled");
+          grpc_chttp2_become_writable(exec_ctx, t, s, true, "unstalled");
         }
       }
       t->flow_control.initial_window_update = 0;
@@ -2959,6 +3002,8 @@ static const grpc_transport_vtable vtable = {sizeof(grpc_chttp2_stream),
                                              chttp2_get_peer,
                                              chttp2_get_endpoint};
 
+static const grpc_transport_vtable *get_vtable(void) { return &vtable; }
+
 grpc_transport *grpc_create_chttp2_transport(
     grpc_exec_ctx *exec_ctx, const grpc_channel_args *channel_args,
     grpc_endpoint *ep, int is_client) {
diff --git a/src/core/ext/transport/chttp2/transport/frame_window_update.c b/src/core/ext/transport/chttp2/transport/frame_window_update.c
index 65f3b01d77..164a97d039 100644
--- a/src/core/ext/transport/chttp2/transport/frame_window_update.c
+++ b/src/core/ext/transport/chttp2/transport/frame_window_update.c
@@ -98,9 +98,8 @@ grpc_error *grpc_chttp2_window_update_parser_parse(
         grpc_chttp2_flowctl_recv_stream_update(
             &t->flow_control, &s->flow_control, received_update);
         if (grpc_chttp2_list_remove_stalled_by_stream(t, s)) {
-          grpc_chttp2_become_writable(
-              exec_ctx, t, s, GRPC_CHTTP2_STREAM_WRITE_INITIATE_UNCOVERED,
-              "stream.read_flow_control");
+          grpc_chttp2_become_writable(exec_ctx, t, s, true,
+                                      "stream.read_flow_control");
         }
       }
     } else {
diff --git a/src/core/ext/transport/chttp2/transport/internal.h b/src/core/ext/transport/chttp2/transport/internal.h
index 3c41a8958f..f0962a6b0e 100644
--- a/src/core/ext/transport/chttp2/transport/internal.h
+++ b/src/core/ext/transport/chttp2/transport/internal.h
@@ -262,6 +262,10 @@ struct grpc_chttp2_transport {
 
   /** write execution state of the transport */
   grpc_chttp2_write_state write_state;
+  /** is this the first write in a series of writes?
+      set when we initiate writing from idle, cleared when we
+      initiate writing from writing+more */
+  bool is_first_write_in_batch;
 
   /** is the transport destroying itself? */
   uint8_t destroying;
@@ -483,6 +487,7 @@ struct grpc_chttp2_stream {
   grpc_slice fetching_slice;
   int64_t next_message_end_offset;
   int64_t flow_controlled_bytes_written;
+  int64_t flow_controlled_bytes_flowed;
   grpc_closure complete_fetch_locked;
   grpc_closure *fetching_send_message_finished;
 
@@ -553,6 +558,7 @@ struct grpc_chttp2_stream {
 
   grpc_slice_buffer flow_controlled_buffer;
 
+  grpc_chttp2_write_cb *on_flow_controlled_cbs;
   grpc_chttp2_write_cb *on_write_finished_cbs;
   grpc_chttp2_write_cb *finish_after_write;
   size_t sending_bytes;
@@ -593,10 +599,13 @@ struct grpc_chttp2_stream {
 void grpc_chttp2_initiate_write(grpc_exec_ctx *exec_ctx,
                                 grpc_chttp2_transport *t, const char *reason);
 
-typedef enum {
-  GRPC_CHTTP2_NOTHING_TO_WRITE,
-  GRPC_CHTTP2_PARTIAL_WRITE,
-  GRPC_CHTTP2_FULL_WRITE,
+typedef struct {
+  /** are we writing? */
+  bool writing;
+  /** if writing: was it a complete flush (false) or a partial flush (true) */
+  bool partial;
+  /** did we queue any completions as part of beginning the write */
+  bool early_results_scheduled;
 } grpc_chttp2_begin_write_result;
 
 grpc_chttp2_begin_write_result grpc_chttp2_begin_write(
@@ -838,22 +847,12 @@ void grpc_chttp2_ack_ping(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
 void grpc_chttp2_add_ping_strike(grpc_exec_ctx *exec_ctx,
                                  grpc_chttp2_transport *t);
 
-typedef enum {
-  /* don't initiate a transport write, but piggyback on the next one */
-  GRPC_CHTTP2_STREAM_WRITE_PIGGYBACK,
-  /* initiate a covered write */
-  GRPC_CHTTP2_STREAM_WRITE_INITIATE_COVERED,
-  /* initiate an uncovered write */
-  GRPC_CHTTP2_STREAM_WRITE_INITIATE_UNCOVERED
-} grpc_chttp2_stream_write_type;
-
 /** add a ref to the stream and add it to the writable list;
     ref will be dropped in writing.c */
 void grpc_chttp2_become_writable(grpc_exec_ctx *exec_ctx,
                                  grpc_chttp2_transport *t,
                                  grpc_chttp2_stream *s,
-                                 grpc_chttp2_stream_write_type type,
-                                 const char *reason);
+                                 bool also_initiate_write, const char *reason);
 
 void grpc_chttp2_cancel_stream(grpc_exec_ctx *exec_ctx,
                                grpc_chttp2_transport *t, grpc_chttp2_stream *s,
diff --git a/src/core/ext/transport/chttp2/transport/parsing.c b/src/core/ext/transport/chttp2/transport/parsing.c
index 18d163ee98..608c94aa30 100644
--- a/src/core/ext/transport/chttp2/transport/parsing.c
+++ b/src/core/ext/transport/chttp2/transport/parsing.c
@@ -106,7 +106,8 @@ grpc_error *grpc_chttp2_perform_read(grpc_exec_ctx *exec_ctx,
           return err;
         }
         ++cur;
-        ++t->deframe_state;
+        t->deframe_state =
+            (grpc_chttp2_deframe_transport_state)(1 + (int)t->deframe_state);
       }
       if (cur == end) {
         return GRPC_ERROR_NONE;
@@ -402,7 +403,7 @@ static void free_timeout(void *p) { gpr_free(p); }
 
 static void on_initial_header(grpc_exec_ctx *exec_ctx, void *tp,
                               grpc_mdelem md) {
-  grpc_chttp2_transport *t = tp;
+  grpc_chttp2_transport *t = (grpc_chttp2_transport *)tp;
   grpc_chttp2_stream *s = t->incoming_stream;
 
   GPR_TIMER_BEGIN("on_initial_header", 0);
@@ -426,11 +427,12 @@ static void on_initial_header(grpc_exec_ctx *exec_ctx, void *tp,
   }
 
   if (grpc_slice_eq(GRPC_MDKEY(md), GRPC_MDSTR_GRPC_TIMEOUT)) {
-    gpr_timespec *cached_timeout = grpc_mdelem_get_user_data(md, free_timeout);
+    gpr_timespec *cached_timeout =
+        (gpr_timespec *)grpc_mdelem_get_user_data(md, free_timeout);
     gpr_timespec timeout;
     if (cached_timeout == NULL) {
       /* not already parsed: parse it now, and store the result away */
-      cached_timeout = gpr_malloc(sizeof(gpr_timespec));
+      cached_timeout = (gpr_timespec *)gpr_malloc(sizeof(gpr_timespec));
       if (!grpc_http2_decode_timeout(GRPC_MDVALUE(md), cached_timeout)) {
         char *val = grpc_slice_to_c_string(GRPC_MDVALUE(md));
         gpr_log(GPR_ERROR, "Ignoring bad timeout value '%s'", val);
@@ -482,7 +484,7 @@ static void on_initial_header(grpc_exec_ctx *exec_ctx, void *tp,
 
 static void on_trailing_header(grpc_exec_ctx *exec_ctx, void *tp,
                                grpc_mdelem md) {
-  grpc_chttp2_transport *t = tp;
+  grpc_chttp2_transport *t = (grpc_chttp2_transport *)tp;
   grpc_chttp2_stream *s = t->incoming_stream;
 
   GPR_TIMER_BEGIN("on_trailing_header", 0);
diff --git a/src/core/ext/transport/chttp2/transport/writing.c b/src/core/ext/transport/chttp2/transport/writing.c
index 711938b278..8abddd778c 100644
--- a/src/core/ext/transport/chttp2/transport/writing.c
+++ b/src/core/ext/transport/chttp2/transport/writing.c
@@ -121,15 +121,18 @@ static void maybe_initiate_ping(grpc_exec_ctx *exec_ctx,
       (t->ping_state.pings_before_data_required != 0);
 }
 
-static void update_list(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
+static bool update_list(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
                         grpc_chttp2_stream *s, int64_t send_bytes,
-                        grpc_chttp2_write_cb **list, grpc_error *error) {
+                        grpc_chttp2_write_cb **list, int64_t *ctr,
+                        grpc_error *error) {
+  bool sched_any = false;
   grpc_chttp2_write_cb *cb = *list;
   *list = NULL;
-  s->flow_controlled_bytes_written += send_bytes;
+  *ctr += send_bytes;
   while (cb) {
     grpc_chttp2_write_cb *next = cb->next;
-    if (cb->call_at_byte <= s->flow_controlled_bytes_written) {
+    if (cb->call_at_byte <= *ctr) {
+      sched_any = true;
       finish_write_cb(exec_ctx, t, s, cb, GRPC_ERROR_REF(error));
     } else {
       add_to_write_list(list, cb);
@@ -137,6 +140,7 @@ static void update_list(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
     cb = next;
   }
   GRPC_ERROR_UNREF(error);
+  return sched_any;
 }
 
 static bool stream_ref_if_not_destroyed(gpr_refcount *r) {
@@ -192,13 +196,13 @@ grpc_chttp2_begin_write_result grpc_chttp2_begin_write(
     }
   }
 
-  bool partial_write = false;
+  grpc_chttp2_begin_write_result result = {false, false, false};
 
   /* for each grpc_chttp2_stream that's become writable, frame it's data
      (according to available window sizes) and add to the output buffer */
   while (true) {
     if (t->outbuf.length > target_write_size(t)) {
-      partial_write = true;
+      result.partial = true;
       break;
     }
 
@@ -242,7 +246,6 @@ grpc_chttp2_begin_write_result grpc_chttp2_begin_write(
             .stats = &s->stats.outgoing};
         grpc_chttp2_encode_header(exec_ctx, &t->hpack_compressor, NULL, 0,
                                   s->send_initial_metadata, &hopt, &t->outbuf);
-        now_writing = true;
         t->ping_state.pings_before_data_required =
             t->ping_policy.max_pings_without_data;
         if (!t->is_client) {
@@ -269,6 +272,10 @@ grpc_chttp2_begin_write_result grpc_chttp2_begin_write(
       s->send_initial_metadata = NULL;
       s->sent_initial_metadata = true;
       sent_initial_metadata = true;
+      result.early_results_scheduled = true;
+      grpc_chttp2_complete_closure_step(
+          exec_ctx, t, s, &s->send_initial_metadata_finished, GRPC_ERROR_NONE,
+          "send_initial_metadata_finished");
     }
     /* send any window updates */
     uint32_t stream_announce = grpc_chttp2_flowctl_maybe_send_stream_update(
@@ -302,6 +309,7 @@ grpc_chttp2_begin_write_result grpc_chttp2_begin_write(
         if (max_outgoing > 0) {
           bool is_last_data_frame = false;
           bool is_last_frame = false;
+          size_t sending_bytes_before = s->sending_bytes;
           if (s->stream_compression_send_enabled) {
             while ((s->flow_controlled_buffer.length > 0 ||
                     s->compressed_data_buffer->length > 0) &&
@@ -369,6 +377,11 @@ grpc_chttp2_begin_write_result grpc_chttp2_begin_write(
                                                     &s->stats.outgoing));
             }
           }
+          result.early_results_scheduled |=
+              update_list(exec_ctx, t, s,
+                          (int64_t)(s->sending_bytes - sending_bytes_before),
+                          &s->on_flow_controlled_cbs,
+                          &s->flow_controlled_bytes_flowed, GRPC_ERROR_NONE);
           now_writing = true;
           if (s->flow_controlled_buffer.length > 0 ||
               (s->stream_compression_send_enabled &&
@@ -420,6 +433,10 @@ grpc_chttp2_begin_write_result grpc_chttp2_begin_write(
                               s->id, GRPC_HTTP2_NO_ERROR, &s->stats.outgoing));
         }
         now_writing = true;
+        result.early_results_scheduled = true;
+        grpc_chttp2_complete_closure_step(
+            exec_ctx, t, s, &s->send_trailing_metadata_finished,
+            GRPC_ERROR_NONE, "send_trailing_metadata_finished");
       }
     }
 
@@ -461,9 +478,8 @@ grpc_chttp2_begin_write_result grpc_chttp2_begin_write(
 
   GPR_TIMER_END("grpc_chttp2_begin_write", 0);
 
-  return t->outbuf.count > 0 ? (partial_write ? GRPC_CHTTP2_PARTIAL_WRITE
-                                              : GRPC_CHTTP2_FULL_WRITE)
-                             : GRPC_CHTTP2_NOTHING_TO_WRITE;
+  result.writing = t->outbuf.count > 0;
+  return result;
 }
 
 void grpc_chttp2_end_write(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
@@ -472,20 +488,13 @@ void grpc_chttp2_end_write(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   grpc_chttp2_stream *s;
 
   while (grpc_chttp2_list_pop_writing_stream(t, &s)) {
-    if (s->sent_initial_metadata) {
-      grpc_chttp2_complete_closure_step(
-          exec_ctx, t, s, &s->send_initial_metadata_finished,
-          GRPC_ERROR_REF(error), "send_initial_metadata_finished");
-    }
     if (s->sending_bytes != 0) {
       update_list(exec_ctx, t, s, (int64_t)s->sending_bytes,
-                  &s->on_write_finished_cbs, GRPC_ERROR_REF(error));
+                  &s->on_write_finished_cbs, &s->flow_controlled_bytes_written,
+                  GRPC_ERROR_REF(error));
       s->sending_bytes = 0;
     }
     if (s->sent_trailing_metadata) {
-      grpc_chttp2_complete_closure_step(
-          exec_ctx, t, s, &s->send_trailing_metadata_finished,
-          GRPC_ERROR_REF(error), "send_trailing_metadata_finished");
       grpc_chttp2_mark_stream_closed(exec_ctx, t, s, !t->is_client, 1,
                                      GRPC_ERROR_REF(error));
     }
diff --git a/src/core/lib/http/httpcli.c b/src/core/lib/http/httpcli.c
index 77af7b7c08..84cc39604c 100644
--- a/src/core/lib/http/httpcli.c
+++ b/src/core/lib/http/httpcli.c
@@ -130,7 +130,7 @@ static void do_read(grpc_exec_ctx *exec_ctx, internal_request *req) {
 
 static void on_read(grpc_exec_ctx *exec_ctx, void *user_data,
                     grpc_error *error) {
-  internal_request *req = user_data;
+  internal_request *req = (internal_request *)user_data;
   size_t i;
 
   for (i = 0; i < req->incoming.count; i++) {
@@ -159,7 +159,7 @@ static void on_written(grpc_exec_ctx *exec_ctx, internal_request *req) {
 }
 
 static void done_write(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
-  internal_request *req = arg;
+  internal_request *req = (internal_request *)arg;
   if (error == GRPC_ERROR_NONE) {
     on_written(exec_ctx, req);
   } else {
@@ -175,7 +175,7 @@ static void start_write(grpc_exec_ctx *exec_ctx, internal_request *req) {
 
 static void on_handshake_done(grpc_exec_ctx *exec_ctx, void *arg,
                               grpc_endpoint *ep) {
-  internal_request *req = arg;
+  internal_request *req = (internal_request *)arg;
 
   if (!ep) {
     next_address(exec_ctx, req, GRPC_ERROR_CREATE_FROM_STATIC_STRING(
@@ -189,7 +189,7 @@ static void on_handshake_done(grpc_exec_ctx *exec_ctx, void *arg,
 
 static void on_connected(grpc_exec_ctx *exec_ctx, void *arg,
                          grpc_error *error) {
-  internal_request *req = arg;
+  internal_request *req = (internal_request *)arg;
 
   if (!req->ep) {
     next_address(exec_ctx, req, GRPC_ERROR_REF(error));
@@ -226,7 +226,7 @@ static void next_address(grpc_exec_ctx *exec_ctx, internal_request *req,
 }
 
 static void on_resolved(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
-  internal_request *req = arg;
+  internal_request *req = (internal_request *)arg;
   if (error != GRPC_ERROR_NONE) {
     finish(exec_ctx, req, GRPC_ERROR_REF(error));
     return;
@@ -243,7 +243,8 @@ static void internal_request_begin(grpc_exec_ctx *exec_ctx,
                                    gpr_timespec deadline, grpc_closure *on_done,
                                    grpc_httpcli_response *response,
                                    const char *name, grpc_slice request_text) {
-  internal_request *req = gpr_malloc(sizeof(internal_request));
+  internal_request *req =
+      (internal_request *)gpr_malloc(sizeof(internal_request));
   memset(req, 0, sizeof(*req));
   req->request_text = request_text;
   grpc_http_parser_init(&req->parser, GRPC_HTTP_RESPONSE, response);
diff --git a/src/core/lib/iomgr/combiner.c b/src/core/lib/iomgr/combiner.c
index 9b66987b68..0e496829f6 100644
--- a/src/core/lib/iomgr/combiner.c
+++ b/src/core/lib/iomgr/combiner.c
@@ -80,7 +80,8 @@ grpc_combiner *grpc_combiner_create(void) {
   gpr_atm_no_barrier_store(&lock->state, STATE_UNORPHANED);
   gpr_mpscq_init(&lock->queue);
   grpc_closure_list_init(&lock->final_list);
-  GRPC_CLOSURE_INIT(&lock->offload, offload, lock, grpc_executor_scheduler);
+  GRPC_CLOSURE_INIT(&lock->offload, offload, lock,
+                    grpc_executor_scheduler(GRPC_EXECUTOR_SHORT));
   GRPC_COMBINER_TRACE(gpr_log(GPR_DEBUG, "C:%p create", lock));
   return lock;
 }
diff --git a/src/core/lib/iomgr/ev_poll_posix.c b/src/core/lib/iomgr/ev_poll_posix.c
index fbd265f3ce..ebf22a8d9d 100644
--- a/src/core/lib/iomgr/ev_poll_posix.c
+++ b/src/core/lib/iomgr/ev_poll_posix.c
@@ -988,6 +988,10 @@ static grpc_error *pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
       r = grpc_poll_function(pfds, pfd_count, timeout);
       GRPC_SCHEDULING_END_BLOCKING_REGION;
 
+      if (GRPC_TRACER_ON(grpc_polling_trace)) {
+        gpr_log(GPR_DEBUG, "%p poll=%d", pollset, r);
+      }
+
       if (r < 0) {
         if (errno != EINTR) {
           work_combine_error(&error, GRPC_OS_ERROR(errno, "poll"));
@@ -1008,6 +1012,9 @@ static grpc_error *pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
         }
       } else {
         if (pfds[0].revents & POLLIN_CHECK) {
+          if (GRPC_TRACER_ON(grpc_polling_trace)) {
+            gpr_log(GPR_DEBUG, "%p: got_wakeup", pollset);
+          }
           work_combine_error(
               &error, grpc_wakeup_fd_consume_wakeup(&worker.wakeup_fd->fd));
         }
@@ -1015,6 +1022,11 @@ static grpc_error *pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
           if (watchers[i].fd == NULL) {
             fd_end_poll(exec_ctx, &watchers[i], 0, 0, NULL);
           } else {
+            if (GRPC_TRACER_ON(grpc_polling_trace)) {
+              gpr_log(GPR_DEBUG, "%p got_event: %d r:%d w:%d [%d]", pollset,
+                      pfds[i].fd, (pfds[i].revents & POLLIN_CHECK) != 0,
+                      (pfds[i].revents & POLLOUT_CHECK) != 0, pfds[i].revents);
+            }
             fd_end_poll(exec_ctx, &watchers[i], pfds[i].revents & POLLIN_CHECK,
                         pfds[i].revents & POLLOUT_CHECK, pollset);
           }
diff --git a/src/core/lib/iomgr/executor.c b/src/core/lib/iomgr/executor.c
index 7621a7fe75..8496ce23c0 100644
--- a/src/core/lib/iomgr/executor.c
+++ b/src/core/lib/iomgr/executor.c
@@ -39,6 +39,7 @@ typedef struct {
   grpc_closure_list elems;
   size_t depth;
   bool shutdown;
+  bool queued_long_job;
   gpr_thd_id id;
 } thread_state;
 
@@ -49,6 +50,9 @@ static gpr_spinlock g_adding_thread_lock = GPR_SPINLOCK_STATIC_INITIALIZER;
 
 GPR_TLS_DECL(g_this_thread_state);
 
+static grpc_tracer_flag executor_trace =
+    GRPC_TRACER_INITIALIZER(false, "executor");
+
 static void executor_thread(void *arg);
 
 static size_t run_closures(grpc_exec_ctx *exec_ctx, grpc_closure_list list) {
@@ -58,6 +62,14 @@ static size_t run_closures(grpc_exec_ctx *exec_ctx, grpc_closure_list list) {
   while (c != NULL) {
     grpc_closure *next = c->next_data.next;
     grpc_error *error = c->error_data.error;
+    if (GRPC_TRACER_ON(executor_trace)) {
+#ifndef NDEBUG
+      gpr_log(GPR_DEBUG, "EXECUTOR: run %p [created by %s:%d]", c,
+              c->file_created, c->line_created);
+#else
+      gpr_log(GPR_DEBUG, "EXECUTOR: run %p", c);
+#endif
+    }
 #ifndef NDEBUG
     c->scheduled = false;
 #endif
@@ -65,6 +77,7 @@ static size_t run_closures(grpc_exec_ctx *exec_ctx, grpc_closure_list list) {
     GRPC_ERROR_UNREF(error);
     c = next;
     n++;
+    grpc_exec_ctx_flush(exec_ctx);
   }
 
   return n;
@@ -119,6 +132,7 @@ void grpc_executor_set_threading(grpc_exec_ctx *exec_ctx, bool threading) {
 }
 
 void grpc_executor_init(grpc_exec_ctx *exec_ctx) {
+  grpc_register_tracer(&executor_trace);
   gpr_atm_no_barrier_store(&g_cur_threads, 0);
   grpc_executor_set_threading(exec_ctx, true);
 }
@@ -136,60 +150,134 @@ static void executor_thread(void *arg) {
 
   size_t subtract_depth = 0;
   for (;;) {
+    if (GRPC_TRACER_ON(executor_trace)) {
+      gpr_log(GPR_DEBUG, "EXECUTOR[%d]: step (sub_depth=%" PRIdPTR ")",
+              (int)(ts - g_thread_state), subtract_depth);
+    }
     gpr_mu_lock(&ts->mu);
     ts->depth -= subtract_depth;
     while (grpc_closure_list_empty(ts->elems) && !ts->shutdown) {
+      ts->queued_long_job = false;
       gpr_cv_wait(&ts->cv, &ts->mu, gpr_inf_future(GPR_CLOCK_REALTIME));
     }
     if (ts->shutdown) {
+      if (GRPC_TRACER_ON(executor_trace)) {
+        gpr_log(GPR_DEBUG, "EXECUTOR[%d]: shutdown",
+                (int)(ts - g_thread_state));
+      }
       gpr_mu_unlock(&ts->mu);
       break;
     }
     grpc_closure_list exec = ts->elems;
     ts->elems = (grpc_closure_list)GRPC_CLOSURE_LIST_INIT;
     gpr_mu_unlock(&ts->mu);
+    if (GRPC_TRACER_ON(executor_trace)) {
+      gpr_log(GPR_DEBUG, "EXECUTOR[%d]: execute", (int)(ts - g_thread_state));
+    }
 
     subtract_depth = run_closures(&exec_ctx, exec);
-    grpc_exec_ctx_flush(&exec_ctx);
   }
   grpc_exec_ctx_finish(&exec_ctx);
 }
 
 static void executor_push(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
-                          grpc_error *error) {
-  size_t cur_thread_count = (size_t)gpr_atm_no_barrier_load(&g_cur_threads);
-  if (cur_thread_count == 0) {
-    grpc_closure_list_append(&exec_ctx->closure_list, closure, error);
-    return;
-  }
-  thread_state *ts = (thread_state *)gpr_tls_get(&g_this_thread_state);
-  if (ts == NULL) {
-    ts = &g_thread_state[GPR_HASH_POINTER(exec_ctx, cur_thread_count)];
-  }
-  gpr_mu_lock(&ts->mu);
-  if (grpc_closure_list_empty(ts->elems)) {
-    gpr_cv_signal(&ts->cv);
-  }
-  grpc_closure_list_append(&ts->elems, closure, error);
-  ts->depth++;
-  bool try_new_thread = ts->depth > MAX_DEPTH &&
-                        cur_thread_count < g_max_threads && !ts->shutdown;
-  gpr_mu_unlock(&ts->mu);
-  if (try_new_thread && gpr_spinlock_trylock(&g_adding_thread_lock)) {
-    cur_thread_count = (size_t)gpr_atm_no_barrier_load(&g_cur_threads);
-    if (cur_thread_count < g_max_threads) {
-      gpr_atm_no_barrier_store(&g_cur_threads, cur_thread_count + 1);
-
-      gpr_thd_options opt = gpr_thd_options_default();
-      gpr_thd_options_set_joinable(&opt);
-      gpr_thd_new(&g_thread_state[cur_thread_count].id, executor_thread,
-                  &g_thread_state[cur_thread_count], &opt);
+                          grpc_error *error, bool is_short) {
+  bool retry_push;
+  do {
+    retry_push = false;
+    size_t cur_thread_count = (size_t)gpr_atm_no_barrier_load(&g_cur_threads);
+    if (cur_thread_count == 0) {
+      if (GRPC_TRACER_ON(executor_trace)) {
+#ifndef NDEBUG
+        gpr_log(GPR_DEBUG, "EXECUTOR: schedule %p (created %s:%d) inline",
+                closure, closure->file_created, closure->line_created);
+#else
+        gpr_log(GPR_DEBUG, "EXECUTOR: schedule %p inline", closure);
+#endif
+      }
+      grpc_closure_list_append(&exec_ctx->closure_list, closure, error);
+      return;
     }
-    gpr_spinlock_unlock(&g_adding_thread_lock);
-  }
+    thread_state *ts = (thread_state *)gpr_tls_get(&g_this_thread_state);
+    if (ts == NULL) {
+      ts = &g_thread_state[GPR_HASH_POINTER(exec_ctx, cur_thread_count)];
+    }
+    thread_state *orig_ts = ts;
+
+    bool try_new_thread;
+    for (;;) {
+      if (GRPC_TRACER_ON(executor_trace)) {
+#ifndef NDEBUG
+        gpr_log(
+            GPR_DEBUG,
+            "EXECUTOR: try to schedule %p (%s) (created %s:%d) to thread %d",
+            closure, is_short ? "short" : "long", closure->file_created,
+            closure->line_created, (int)(ts - g_thread_state));
+#else
+        gpr_log(GPR_DEBUG, "EXECUTOR: try to schedule %p (%s) to thread %d",
+                closure, is_short ? "short" : "long",
+                (int)(ts - g_thread_state));
+#endif
+      }
+      gpr_mu_lock(&ts->mu);
+      if (ts->queued_long_job) {
+        gpr_mu_unlock(&ts->mu);
+        size_t idx = (size_t)(ts - g_thread_state);
+        ts = &g_thread_state[(idx + 1) % cur_thread_count];
+        if (ts == orig_ts) {
+          retry_push = true;
+          try_new_thread = true;
+          break;
+        }
+        continue;
+      }
+      if (grpc_closure_list_empty(ts->elems)) {
+        gpr_cv_signal(&ts->cv);
+      }
+      grpc_closure_list_append(&ts->elems, closure, error);
+      ts->depth++;
+      try_new_thread = ts->depth > MAX_DEPTH &&
+                       cur_thread_count < g_max_threads && !ts->shutdown;
+      if (!is_short) ts->queued_long_job = true;
+      gpr_mu_unlock(&ts->mu);
+      break;
+    }
+    if (try_new_thread && gpr_spinlock_trylock(&g_adding_thread_lock)) {
+      cur_thread_count = (size_t)gpr_atm_no_barrier_load(&g_cur_threads);
+      if (cur_thread_count < g_max_threads) {
+        gpr_atm_no_barrier_store(&g_cur_threads, cur_thread_count + 1);
+
+        gpr_thd_options opt = gpr_thd_options_default();
+        gpr_thd_options_set_joinable(&opt);
+        gpr_thd_new(&g_thread_state[cur_thread_count].id, executor_thread,
+                    &g_thread_state[cur_thread_count], &opt);
+      }
+      gpr_spinlock_unlock(&g_adding_thread_lock);
+    }
+  } while (retry_push);
 }
 
-static const grpc_closure_scheduler_vtable executor_vtable = {
-    executor_push, executor_push, "executor"};
-static grpc_closure_scheduler executor_scheduler = {&executor_vtable};
-grpc_closure_scheduler *grpc_executor_scheduler = &executor_scheduler;
+static void executor_push_short(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
+                                grpc_error *error) {
+  executor_push(exec_ctx, closure, error, true);
+}
+
+static void executor_push_long(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
+                               grpc_error *error) {
+  executor_push(exec_ctx, closure, error, false);
+}
+
+static const grpc_closure_scheduler_vtable executor_vtable_short = {
+    executor_push_short, executor_push_short, "executor"};
+static grpc_closure_scheduler executor_scheduler_short = {
+    &executor_vtable_short};
+
+static const grpc_closure_scheduler_vtable executor_vtable_long = {
+    executor_push_long, executor_push_long, "executor"};
+static grpc_closure_scheduler executor_scheduler_long = {&executor_vtable_long};
+
+grpc_closure_scheduler *grpc_executor_scheduler(
+    grpc_executor_job_length length) {
+  return length == GRPC_EXECUTOR_SHORT ? &executor_scheduler_short
+                                       : &executor_scheduler_long;
+}
diff --git a/src/core/lib/iomgr/executor.h b/src/core/lib/iomgr/executor.h
index c3382a0a12..0412c02790 100644
--- a/src/core/lib/iomgr/executor.h
+++ b/src/core/lib/iomgr/executor.h
@@ -21,6 +21,11 @@
 
 #include "src/core/lib/iomgr/closure.h"
 
+typedef enum {
+  GRPC_EXECUTOR_SHORT,
+  GRPC_EXECUTOR_LONG
+} grpc_executor_job_length;
+
 /** Initialize the global executor.
  *
  * This mechanism is meant to outsource work (grpc_closure instances) to a
@@ -28,7 +33,7 @@
  * non-blocking solution available. */
 void grpc_executor_init(grpc_exec_ctx *exec_ctx);
 
-extern grpc_closure_scheduler *grpc_executor_scheduler;
+grpc_closure_scheduler *grpc_executor_scheduler(grpc_executor_job_length);
 
 /** Shutdown the executor, running all pending work as part of the call */
 void grpc_executor_shutdown(grpc_exec_ctx *exec_ctx);
diff --git a/src/core/lib/iomgr/resolve_address_posix.c b/src/core/lib/iomgr/resolve_address_posix.c
index 35dedc23de..2bb00e5eed 100644
--- a/src/core/lib/iomgr/resolve_address_posix.c
+++ b/src/core/lib/iomgr/resolve_address_posix.c
@@ -176,7 +176,7 @@ static void resolve_address_impl(grpc_exec_ctx *exec_ctx, const char *name,
                                  grpc_resolved_addresses **addrs) {
   request *r = gpr_malloc(sizeof(request));
   GRPC_CLOSURE_INIT(&r->request_closure, do_request_thread, r,
-                    grpc_executor_scheduler);
+                    grpc_executor_scheduler(GRPC_EXECUTOR_SHORT));
   r->name = gpr_strdup(name);
   r->default_port = gpr_strdup(default_port);
   r->on_done = on_done;
diff --git a/src/core/lib/iomgr/resolve_address_windows.c b/src/core/lib/iomgr/resolve_address_windows.c
index 45cfd7248d..0cb0029f4e 100644
--- a/src/core/lib/iomgr/resolve_address_windows.c
+++ b/src/core/lib/iomgr/resolve_address_windows.c
@@ -159,7 +159,7 @@ static void resolve_address_impl(grpc_exec_ctx *exec_ctx, const char *name,
                                  grpc_resolved_addresses **addresses) {
   request *r = gpr_malloc(sizeof(request));
   GRPC_CLOSURE_INIT(&r->request_closure, do_request_thread, r,
-                    grpc_executor_scheduler);
+                    grpc_executor_scheduler(GRPC_EXECUTOR_SHORT));
   r->name = gpr_strdup(name);
   r->default_port = gpr_strdup(default_port);
   r->on_done = on_done;
diff --git a/src/core/lib/iomgr/tcp_posix.c b/src/core/lib/iomgr/tcp_posix.c
index 6c620ca245..b15b6d8746 100644
--- a/src/core/lib/iomgr/tcp_posix.c
+++ b/src/core/lib/iomgr/tcp_posix.c
@@ -43,6 +43,7 @@
 #include "src/core/lib/debug/stats.h"
 #include "src/core/lib/debug/trace.h"
 #include "src/core/lib/iomgr/ev_posix.h"
+#include "src/core/lib/iomgr/executor.h"
 #include "src/core/lib/profiling/timers.h"
 #include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
@@ -90,8 +91,8 @@ typedef struct {
   grpc_closure *release_fd_cb;
   int *release_fd;
 
-  grpc_closure read_closure;
-  grpc_closure write_closure;
+  grpc_closure read_done_closure;
+  grpc_closure write_done_closure;
 
   char *peer_string;
 
@@ -99,6 +100,145 @@ typedef struct {
   grpc_resource_user_slice_allocator slice_allocator;
 } grpc_tcp;
 
+typedef struct backup_poller {
+  gpr_mu *pollset_mu;
+  grpc_closure run_poller;
+} backup_poller;
+
+#define BACKUP_POLLER_POLLSET(b) ((grpc_pollset *)((b) + 1))
+
+static gpr_atm g_uncovered_notifications_pending;
+static gpr_atm g_backup_poller; /* backup_poller* */
+
+static void tcp_handle_read(grpc_exec_ctx *exec_ctx, void *arg /* grpc_tcp */,
+                            grpc_error *error);
+static void tcp_handle_write(grpc_exec_ctx *exec_ctx, void *arg /* grpc_tcp */,
+                             grpc_error *error);
+static void tcp_drop_uncovered_then_handle_write(grpc_exec_ctx *exec_ctx,
+                                                 void *arg /* grpc_tcp */,
+                                                 grpc_error *error);
+
+static void done_poller(grpc_exec_ctx *exec_ctx, void *bp,
+                        grpc_error *error_ignored) {
+  backup_poller *p = (backup_poller *)bp;
+  if (GRPC_TRACER_ON(grpc_tcp_trace)) {
+    gpr_log(GPR_DEBUG, "BACKUP_POLLER:%p destroy", p);
+  }
+  grpc_pollset_destroy(exec_ctx, BACKUP_POLLER_POLLSET(p));
+  gpr_free(p);
+}
+
+static void run_poller(grpc_exec_ctx *exec_ctx, void *bp,
+                       grpc_error *error_ignored) {
+  backup_poller *p = (backup_poller *)bp;
+  if (GRPC_TRACER_ON(grpc_tcp_trace)) {
+    gpr_log(GPR_DEBUG, "BACKUP_POLLER:%p run", p);
+  }
+  gpr_mu_lock(p->pollset_mu);
+  gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
+  gpr_timespec deadline =
+      gpr_time_add(now, gpr_time_from_seconds(10, GPR_TIMESPAN));
+  GRPC_LOG_IF_ERROR("backup_poller:pollset_work",
+                    grpc_pollset_work(exec_ctx, BACKUP_POLLER_POLLSET(p), NULL,
+                                      now, deadline));
+  gpr_mu_unlock(p->pollset_mu);
+  /* last "uncovered" notification is the ref that keeps us polling, if we get
+   * there try a cas to release it */
+  if (gpr_atm_no_barrier_load(&g_uncovered_notifications_pending) == 1 &&
+      gpr_atm_full_cas(&g_uncovered_notifications_pending, 1, 0)) {
+    gpr_mu_lock(p->pollset_mu);
+    bool cas_ok = gpr_atm_no_barrier_cas(&g_backup_poller, (gpr_atm)p, 0);
+    if (GRPC_TRACER_ON(grpc_tcp_trace)) {
+      gpr_log(GPR_DEBUG, "BACKUP_POLLER:%p done cas_ok=%d", p, cas_ok);
+    }
+    gpr_mu_unlock(p->pollset_mu);
+    if (GRPC_TRACER_ON(grpc_tcp_trace)) {
+      gpr_log(GPR_DEBUG, "BACKUP_POLLER:%p shutdown", p);
+    }
+    grpc_pollset_shutdown(exec_ctx, BACKUP_POLLER_POLLSET(p),
+                          GRPC_CLOSURE_INIT(&p->run_poller, done_poller, p,
+                                            grpc_schedule_on_exec_ctx));
+  } else {
+    if (GRPC_TRACER_ON(grpc_tcp_trace)) {
+      gpr_log(GPR_DEBUG, "BACKUP_POLLER:%p reschedule", p);
+    }
+    GRPC_CLOSURE_SCHED(exec_ctx, &p->run_poller, GRPC_ERROR_NONE);
+  }
+}
+
+static void drop_uncovered(grpc_exec_ctx *exec_ctx, grpc_tcp *tcp) {
+  backup_poller *p = (backup_poller *)gpr_atm_no_barrier_load(&g_backup_poller);
+  gpr_atm old_count =
+      gpr_atm_no_barrier_fetch_add(&g_uncovered_notifications_pending, -1);
+  if (GRPC_TRACER_ON(grpc_tcp_trace)) {
+    gpr_log(GPR_DEBUG, "BACKUP_POLLER:%p uncover cnt %d->%d", p, (int)old_count,
+            (int)old_count - 1);
+  }
+  GPR_ASSERT(old_count != 1);
+}
+
+static void cover_self(grpc_exec_ctx *exec_ctx, grpc_tcp *tcp) {
+  backup_poller *p;
+  gpr_atm old_count =
+      gpr_atm_no_barrier_fetch_add(&g_uncovered_notifications_pending, 2);
+  if (GRPC_TRACER_ON(grpc_tcp_trace)) {
+    gpr_log(GPR_DEBUG, "BACKUP_POLLER: cover cnt %d->%d", (int)old_count,
+            2 + (int)old_count);
+  }
+  if (old_count == 0) {
+    p = (backup_poller *)gpr_malloc(sizeof(*p) + grpc_pollset_size());
+    if (GRPC_TRACER_ON(grpc_tcp_trace)) {
+      gpr_log(GPR_DEBUG, "BACKUP_POLLER:%p create", p);
+    }
+    grpc_pollset_init(BACKUP_POLLER_POLLSET(p), &p->pollset_mu);
+    gpr_atm_no_barrier_store(&g_backup_poller, (gpr_atm)p);
+    GRPC_CLOSURE_SCHED(
+        exec_ctx,
+        GRPC_CLOSURE_INIT(&p->run_poller, run_poller, p,
+                          grpc_executor_scheduler(GRPC_EXECUTOR_LONG)),
+        GRPC_ERROR_NONE);
+  } else {
+    p = (backup_poller *)gpr_atm_no_barrier_load(&g_backup_poller);
+    GPR_ASSERT(p != NULL);
+  }
+  if (GRPC_TRACER_ON(grpc_tcp_trace)) {
+    gpr_log(GPR_DEBUG, "BACKUP_POLLER:%p add %p", p, tcp);
+  }
+  grpc_pollset_add_fd(exec_ctx, BACKUP_POLLER_POLLSET(p), tcp->em_fd);
+  if (old_count != 0) {
+    drop_uncovered(exec_ctx, tcp);
+  }
+}
+
+static void notify_on_read(grpc_exec_ctx *exec_ctx, grpc_tcp *tcp) {
+  if (GRPC_TRACER_ON(grpc_tcp_trace)) {
+    gpr_log(GPR_DEBUG, "TCP:%p notify_on_read", tcp);
+  }
+  GRPC_CLOSURE_INIT(&tcp->read_done_closure, tcp_handle_read, tcp,
+                    grpc_schedule_on_exec_ctx);
+  grpc_fd_notify_on_read(exec_ctx, tcp->em_fd, &tcp->read_done_closure);
+}
+
+static void notify_on_write(grpc_exec_ctx *exec_ctx, grpc_tcp *tcp) {
+  if (GRPC_TRACER_ON(grpc_tcp_trace)) {
+    gpr_log(GPR_DEBUG, "TCP:%p notify_on_write", tcp);
+  }
+  cover_self(exec_ctx, tcp);
+  GRPC_CLOSURE_INIT(&tcp->write_done_closure,
+                    tcp_drop_uncovered_then_handle_write, tcp,
+                    grpc_schedule_on_exec_ctx);
+  grpc_fd_notify_on_write(exec_ctx, tcp->em_fd, &tcp->write_done_closure);
+}
+
+static void tcp_drop_uncovered_then_handle_write(grpc_exec_ctx *exec_ctx,
+                                                 void *arg, grpc_error *error) {
+  if (GRPC_TRACER_ON(grpc_tcp_trace)) {
+    gpr_log(GPR_DEBUG, "TCP:%p got_write: %s", arg, grpc_error_string(error));
+  }
+  drop_uncovered(exec_ctx, (grpc_tcp *)arg);
+  tcp_handle_write(exec_ctx, arg, error);
+}
+
 static void add_to_estimate(grpc_tcp *tcp, size_t bytes) {
   tcp->bytes_read_this_round += (double)bytes;
 }
@@ -214,6 +354,7 @@ static void call_read_cb(grpc_exec_ctx *exec_ctx, grpc_tcp *tcp,
   grpc_closure *cb = tcp->read_cb;
 
   if (GRPC_TRACER_ON(grpc_tcp_trace)) {
+    gpr_log(GPR_DEBUG, "TCP:%p call_cb %p %p:%p", tcp, cb, cb->cb, cb->cb_arg);
     size_t i;
     const char *str = grpc_error_string(error);
     gpr_log(GPR_DEBUG, "read: error=%s", str);
@@ -268,7 +409,7 @@ static void tcp_do_read(grpc_exec_ctx *exec_ctx, grpc_tcp *tcp) {
     if (errno == EAGAIN) {
       finish_estimate(tcp);
       /* We've consumed the edge, request a new one */
-      grpc_fd_notify_on_read(exec_ctx, tcp->em_fd, &tcp->read_closure);
+      notify_on_read(exec_ctx, tcp);
     } else {
       grpc_slice_buffer_reset_and_unref_internal(exec_ctx,
                                                  tcp->incoming_buffer);
@@ -303,7 +444,11 @@ static void tcp_do_read(grpc_exec_ctx *exec_ctx, grpc_tcp *tcp) {
 
 static void tcp_read_allocation_done(grpc_exec_ctx *exec_ctx, void *tcpp,
                                      grpc_error *error) {
-  grpc_tcp *tcp = tcpp;
+  grpc_tcp *tcp = (grpc_tcp *)tcpp;
+  if (GRPC_TRACER_ON(grpc_tcp_trace)) {
+    gpr_log(GPR_DEBUG, "TCP:%p read_allocation_done: %s", tcp,
+            grpc_error_string(error));
+  }
   if (error != GRPC_ERROR_NONE) {
     grpc_slice_buffer_reset_and_unref_internal(exec_ctx, tcp->incoming_buffer);
     grpc_slice_buffer_reset_and_unref_internal(exec_ctx,
@@ -319,9 +464,15 @@ static void tcp_continue_read(grpc_exec_ctx *exec_ctx, grpc_tcp *tcp) {
   size_t target_read_size = get_target_read_size(tcp);
   if (tcp->incoming_buffer->length < target_read_size &&
       tcp->incoming_buffer->count < MAX_READ_IOVEC) {
+    if (GRPC_TRACER_ON(grpc_tcp_trace)) {
+      gpr_log(GPR_DEBUG, "TCP:%p alloc_slices", tcp);
+    }
     grpc_resource_user_alloc_slices(exec_ctx, &tcp->slice_allocator,
                                     target_read_size, 1, tcp->incoming_buffer);
   } else {
+    if (GRPC_TRACER_ON(grpc_tcp_trace)) {
+      gpr_log(GPR_DEBUG, "TCP:%p do_read", tcp);
+    }
     tcp_do_read(exec_ctx, tcp);
   }
 }
@@ -330,6 +481,9 @@ static void tcp_handle_read(grpc_exec_ctx *exec_ctx, void *arg /* grpc_tcp */,
                             grpc_error *error) {
   grpc_tcp *tcp = (grpc_tcp *)arg;
   GPR_ASSERT(!tcp->finished_edge);
+  if (GRPC_TRACER_ON(grpc_tcp_trace)) {
+    gpr_log(GPR_DEBUG, "TCP:%p got_read: %s", tcp, grpc_error_string(error));
+  }
 
   if (error != GRPC_ERROR_NONE) {
     grpc_slice_buffer_reset_and_unref_internal(exec_ctx, tcp->incoming_buffer);
@@ -353,9 +507,9 @@ static void tcp_read(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
   TCP_REF(tcp, "read");
   if (tcp->finished_edge) {
     tcp->finished_edge = false;
-    grpc_fd_notify_on_read(exec_ctx, tcp->em_fd, &tcp->read_closure);
+    notify_on_read(exec_ctx, tcp);
   } else {
-    GRPC_CLOSURE_SCHED(exec_ctx, &tcp->read_closure, GRPC_ERROR_NONE);
+    GRPC_CLOSURE_SCHED(exec_ctx, &tcp->read_done_closure, GRPC_ERROR_NONE);
   }
 }
 
@@ -465,7 +619,7 @@ static void tcp_handle_write(grpc_exec_ctx *exec_ctx, void *arg /* grpc_tcp */,
     if (GRPC_TRACER_ON(grpc_tcp_trace)) {
       gpr_log(GPR_DEBUG, "write: delayed");
     }
-    grpc_fd_notify_on_write(exec_ctx, tcp->em_fd, &tcp->write_closure);
+    notify_on_write(exec_ctx, tcp);
   } else {
     cb = tcp->write_cb;
     tcp->write_cb = NULL;
@@ -518,7 +672,7 @@ static void tcp_write(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
     if (GRPC_TRACER_ON(grpc_tcp_trace)) {
       gpr_log(GPR_DEBUG, "write: delayed");
     }
-    grpc_fd_notify_on_write(exec_ctx, tcp->em_fd, &tcp->write_closure);
+    notify_on_write(exec_ctx, tcp);
   } else {
     if (GRPC_TRACER_ON(grpc_tcp_trace)) {
       const char *str = grpc_error_string(error);
@@ -595,7 +749,7 @@ grpc_endpoint *grpc_tcp_create(grpc_exec_ctx *exec_ctx, grpc_fd *em_fd,
                  strcmp(channel_args->args[i].key, GRPC_ARG_RESOURCE_QUOTA)) {
         grpc_resource_quota_unref_internal(exec_ctx, resource_quota);
         resource_quota = grpc_resource_quota_ref_internal(
-            channel_args->args[i].value.pointer.p);
+            (grpc_resource_quota *)channel_args->args[i].value.pointer.p);
       }
     }
   }
@@ -624,10 +778,6 @@ grpc_endpoint *grpc_tcp_create(grpc_exec_ctx *exec_ctx, grpc_fd *em_fd,
   gpr_ref_init(&tcp->refcount, 1);
   gpr_atm_no_barrier_store(&tcp->shutdown_count, 0);
   tcp->em_fd = em_fd;
-  GRPC_CLOSURE_INIT(&tcp->read_closure, tcp_handle_read, tcp,
-                    grpc_schedule_on_exec_ctx);
-  GRPC_CLOSURE_INIT(&tcp->write_closure, tcp_handle_write, tcp,
-                    grpc_schedule_on_exec_ctx);
   grpc_slice_buffer_init(&tcp->last_read_buffer);
   tcp->resource_user = grpc_resource_user_create(resource_quota, peer_string);
   grpc_resource_user_slice_allocator_init(
diff --git a/src/core/lib/security/transport/security_handshaker.c b/src/core/lib/security/transport/security_handshaker.c
index fc9c9f980f..bf7a5272cb 100644
--- a/src/core/lib/security/transport/security_handshaker.c
+++ b/src/core/lib/security/transport/security_handshaker.c
@@ -127,13 +127,11 @@ static void security_handshake_failed_locked(grpc_exec_ctx *exec_ctx,
   GRPC_CLOSURE_SCHED(exec_ctx, h->on_handshake_done, error);
 }
 
-static void on_peer_checked(grpc_exec_ctx *exec_ctx, void *arg,
-                            grpc_error *error) {
-  security_handshaker *h = arg;
-  gpr_mu_lock(&h->mu);
+static void on_peer_checked_inner(grpc_exec_ctx *exec_ctx,
+                                  security_handshaker *h, grpc_error *error) {
   if (error != GRPC_ERROR_NONE || h->shutdown) {
     security_handshake_failed_locked(exec_ctx, h, GRPC_ERROR_REF(error));
-    goto done;
+    return;
   }
   // Create frame protector.
   tsi_frame_protector *protector;
@@ -144,7 +142,7 @@ static void on_peer_checked(grpc_exec_ctx *exec_ctx, void *arg,
         GRPC_ERROR_CREATE_FROM_STATIC_STRING("Frame protector creation failed"),
         result);
     security_handshake_failed_locked(exec_ctx, h, error);
-    goto done;
+    return;
   }
   // Get unused bytes.
   const unsigned char *unused_bytes = NULL;
@@ -177,7 +175,13 @@ static void on_peer_checked(grpc_exec_ctx *exec_ctx, void *arg,
   // Set shutdown to true so that subsequent calls to
   // security_handshaker_shutdown() do nothing.
   h->shutdown = true;
-done:
+}
+
+static void on_peer_checked(grpc_exec_ctx *exec_ctx, void *arg,
+                            grpc_error *error) {
+  security_handshaker *h = (security_handshaker *)arg;
+  gpr_mu_lock(&h->mu);
+  on_peer_checked_inner(exec_ctx, h, error);
   gpr_mu_unlock(&h->mu);
   security_handshaker_unref(exec_ctx, h);
 }
@@ -239,7 +243,7 @@ static grpc_error *on_handshake_next_done_locked(
 static void on_handshake_next_done_grpc_wrapper(
     tsi_result result, void *user_data, const unsigned char *bytes_to_send,
     size_t bytes_to_send_size, tsi_handshaker_result *handshaker_result) {
-  security_handshaker *h = user_data;
+  security_handshaker *h = (security_handshaker *)user_data;
   // This callback will be invoked by TSI in a non-grpc thread, so it's
   // safe to create our own exec_ctx here.
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
@@ -281,7 +285,7 @@ static grpc_error *do_handshaker_next_locked(
 
 static void on_handshake_data_received_from_peer(grpc_exec_ctx *exec_ctx,
                                                  void *arg, grpc_error *error) {
-  security_handshaker *h = arg;
+  security_handshaker *h = (security_handshaker *)arg;
   gpr_mu_lock(&h->mu);
   if (error != GRPC_ERROR_NONE || h->shutdown) {
     security_handshake_failed_locked(
@@ -298,7 +302,8 @@ static void on_handshake_data_received_from_peer(grpc_exec_ctx *exec_ctx,
     bytes_received_size += GRPC_SLICE_LENGTH(h->args->read_buffer->slices[i]);
   }
   if (bytes_received_size > h->handshake_buffer_size) {
-    h->handshake_buffer = gpr_realloc(h->handshake_buffer, bytes_received_size);
+    h->handshake_buffer =
+        (uint8_t *)gpr_realloc(h->handshake_buffer, bytes_received_size);
     h->handshake_buffer_size = bytes_received_size;
   }
   size_t offset = 0;
@@ -323,7 +328,7 @@ static void on_handshake_data_received_from_peer(grpc_exec_ctx *exec_ctx,
 
 static void on_handshake_data_sent_to_peer(grpc_exec_ctx *exec_ctx, void *arg,
                                            grpc_error *error) {
-  security_handshaker *h = arg;
+  security_handshaker *h = (security_handshaker *)arg;
   gpr_mu_lock(&h->mu);
   if (error != GRPC_ERROR_NONE || h->shutdown) {
     security_handshake_failed_locked(
@@ -400,14 +405,15 @@ static const grpc_handshaker_vtable security_handshaker_vtable = {
 static grpc_handshaker *security_handshaker_create(
     grpc_exec_ctx *exec_ctx, tsi_handshaker *handshaker,
     grpc_security_connector *connector) {
-  security_handshaker *h = gpr_zalloc(sizeof(security_handshaker));
+  security_handshaker *h =
+      (security_handshaker *)gpr_zalloc(sizeof(security_handshaker));
   grpc_handshaker_init(&security_handshaker_vtable, &h->base);
   h->handshaker = handshaker;
   h->connector = GRPC_SECURITY_CONNECTOR_REF(connector, "handshake");
   gpr_mu_init(&h->mu);
   gpr_ref_init(&h->refs, 1);
   h->handshake_buffer_size = GRPC_INITIAL_HANDSHAKE_BUFFER_SIZE;
-  h->handshake_buffer = gpr_malloc(h->handshake_buffer_size);
+  h->handshake_buffer = (uint8_t *)gpr_malloc(h->handshake_buffer_size);
   GRPC_CLOSURE_INIT(&h->on_handshake_data_sent_to_peer,
                     on_handshake_data_sent_to_peer, h,
                     grpc_schedule_on_exec_ctx);
@@ -450,7 +456,7 @@ static const grpc_handshaker_vtable fail_handshaker_vtable = {
     fail_handshaker_do_handshake};
 
 static grpc_handshaker *fail_handshaker_create() {
-  grpc_handshaker *h = gpr_malloc(sizeof(*h));
+  grpc_handshaker *h = (grpc_handshaker *)gpr_malloc(sizeof(*h));
   grpc_handshaker_init(&fail_handshaker_vtable, h);
   return h;
 }
diff --git a/src/core/lib/surface/server.c b/src/core/lib/surface/server.c
index 66dcc299aa..f8c84fb4a8 100644
--- a/src/core/lib/surface/server.c
+++ b/src/core/lib/surface/server.c
@@ -1116,9 +1116,11 @@ void grpc_server_start(grpc_server *server) {
 
   server_ref(server);
   server->starting = true;
-  GRPC_CLOSURE_SCHED(&exec_ctx, GRPC_CLOSURE_CREATE(start_listeners, server,
-                                                    grpc_executor_scheduler),
-                     GRPC_ERROR_NONE);
+  GRPC_CLOSURE_SCHED(
+      &exec_ctx,
+      GRPC_CLOSURE_CREATE(start_listeners, server,
+                          grpc_executor_scheduler(GRPC_EXECUTOR_SHORT)),
+      GRPC_ERROR_NONE);
 
   grpc_exec_ctx_finish(&exec_ctx);
 }
diff --git a/src/core/lib/transport/transport.c b/src/core/lib/transport/transport.c
index 6c61f4b8d9..0ca7688ca4 100644
--- a/src/core/lib/transport/transport.c
+++ b/src/core/lib/transport/transport.c
@@ -72,7 +72,8 @@ void grpc_stream_unref(grpc_exec_ctx *exec_ctx,
          cope with.
          Throw this over to the executor (on a core-owned thread) and process it
          there. */
-      refcount->destroy.scheduler = grpc_executor_scheduler;
+      refcount->destroy.scheduler =
+          grpc_executor_scheduler(GRPC_EXECUTOR_SHORT);
     }
     GRPC_CLOSURE_SCHED(exec_ctx, &refcount->destroy, GRPC_ERROR_NONE);
   }