Initial gevent support

Because some cpp code ends up leaking into cython, we change
the cython generator to generate cpp code.

20 files changed, 881 insertions, 80 deletions

diff --git a/.gitignore b/.gitignore
index 0f3cd78947..cde82bc3d3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,8 +15,10 @@ python_pylint_venv/
 htmlcov/
 dist/
 *.egg
-py27/
-py3[0-9]*/
+py27_gevent/
+py27_native/
+py3[0-9]_gevent/
+py3[0-9]_native/
 
 # Node installation output
 node_modules
diff --git a/setup.py b/setup.py
index 7c07c5614c..a45c350382 100644
--- a/setup.py
+++ b/setup.py
@@ -103,9 +103,9 @@ ENABLE_DOCUMENTATION_BUILD = os.environ.get(
 EXTRA_ENV_COMPILE_ARGS = os.environ.get('GRPC_PYTHON_CFLAGS', None)
 EXTRA_ENV_LINK_ARGS = os.environ.get('GRPC_PYTHON_LDFLAGS', None)
 if EXTRA_ENV_COMPILE_ARGS is None:
-  EXTRA_ENV_COMPILE_ARGS = ''
+  EXTRA_ENV_COMPILE_ARGS = ' -std=c++11'
   if 'win32' in sys.platform and sys.version_info < (3, 5):
-    EXTRA_ENV_COMPILE_ARGS += ' -std=c++11'
+    EXTRA_ENV_COMPILE_ARGS += ' -D_hypot=hypot'
     # We use define flags here and don't directly add to DEFINE_MACROS below to
     # ensure that the expert user/builder has a way of turning it off (via the
     # envvars) without adding yet more GRPC-specific envvars.
@@ -115,10 +115,10 @@ if EXTRA_ENV_COMPILE_ARGS is None:
     else:
       EXTRA_ENV_COMPILE_ARGS += ' -D_ftime=_ftime64 -D_timeb=__timeb64'
   elif "linux" in sys.platform:
-    EXTRA_ENV_COMPILE_ARGS += ' -std=c++11 -std=gnu99 -fvisibility=hidden -fno-wrapv -fno-exceptions'
+    EXTRA_ENV_COMPILE_ARGS += ' -std=gnu99 -fvisibility=hidden -fno-wrapv -fno-exceptions'
   elif "darwin" in sys.platform:
     EXTRA_ENV_COMPILE_ARGS += ' -fvisibility=hidden -fno-wrapv -fno-exceptions'
-EXTRA_ENV_COMPILE_ARGS += ' -DPB_FIELD_16BIT'	
+EXTRA_ENV_COMPILE_ARGS += ' -DPB_FIELD_16BIT'
 
 if EXTRA_ENV_LINK_ARGS is None:
   EXTRA_ENV_LINK_ARGS = ''
@@ -181,7 +181,7 @@ LDFLAGS = tuple(EXTRA_LINK_ARGS)
 CFLAGS = tuple(EXTRA_COMPILE_ARGS)
 if "linux" in sys.platform or "darwin" in sys.platform:
   pymodinit_type = 'PyObject*' if PY3 else 'void'
-  pymodinit = '__attribute__((visibility ("default"))) {}'.format(pymodinit_type)
+  pymodinit = 'extern "C" __attribute__((visibility ("default"))) {}'.format(pymodinit_type)
   DEFINE_MACROS += (('PyMODINIT_FUNC', pymodinit),)
   DEFINE_MACROS += (('GRPC_POSIX_FORK_ALLOW_PTHREAD_ATFORK', 1),)
 
diff --git a/src/core/lib/iomgr/gevent_util.h b/src/core/lib/iomgr/gevent_util.h
new file mode 100644
index 0000000000..de30543e3a
--- /dev/null
+++ b/src/core/lib/iomgr/gevent_util.h
@@ -0,0 +1,46 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_IOMGR_GEVENT_UTIL_H
+#define GRPC_CORE_LIB_IOMGR_GEVENT_UTIL_H
+
+#include <grpc/support/port_platform.h>
+
+#include <grpc/impl/codegen/slice.h>
+#include <grpc/status.h>
+#include "src/core/lib/iomgr/error.h"
+
+// These are only used by the gRPC Python extension for gevent
+// support.  They are easier to define here (rather than in Cython)
+// because Cython doesn't handle #defines well.
+
+grpc_error* grpc_socket_error(char* error) {
+  return grpc_error_set_int(GRPC_ERROR_CREATE_FROM_COPIED_STRING(error),
+                            GRPC_ERROR_INT_GRPC_STATUS,
+                            GRPC_STATUS_UNAVAILABLE);
+}
+
+char* grpc_slice_buffer_start(grpc_slice_buffer* buffer, int i) {
+  return (char*)GRPC_SLICE_START_PTR(buffer->slices[i]);
+}
+
+int grpc_slice_buffer_length(grpc_slice_buffer* buffer, int i) {
+  return GRPC_SLICE_LENGTH(buffer->slices[i]);
+}
+
+#endif
diff --git a/src/core/lib/iomgr/port.h b/src/core/lib/iomgr/port.h
index c1dcc52618..a397012003 100644
--- a/src/core/lib/iomgr/port.h
+++ b/src/core/lib/iomgr/port.h
@@ -22,8 +22,10 @@
 #define GRPC_CORE_LIB_IOMGR_PORT_H
 
 #ifdef GRPC_UV
+#ifndef GRPC_CUSTOM_SOCKET
 #define GRPC_CUSTOM_SOCKET
 #endif
+#endif
 #if defined(GRPC_CUSTOM_SOCKET)
 // Do Nothing
 #elif defined(GPR_MANYLINUX1)
diff --git a/src/core/lib/iomgr/sockaddr_utils.cc b/src/core/lib/iomgr/sockaddr_utils.cc
index df25f7778a..1b66dceb13 100644
--- a/src/core/lib/iomgr/sockaddr_utils.cc
+++ b/src/core/lib/iomgr/sockaddr_utils.cc
@@ -204,6 +204,8 @@ void grpc_string_to_sockaddr(grpc_resolved_address* out, char* addr, int port) {
 
   if (grpc_inet_pton(GRPC_AF_INET6, addr, &addr6->sin6_addr) == 1) {
     addr6->sin6_family = GRPC_AF_INET6;
+    addr6->sin6_flowinfo = 0;
+    addr6->sin6_scope_id = 0;
     out->len = sizeof(grpc_sockaddr_in6);
   } else if (grpc_inet_pton(GRPC_AF_INET, addr, &addr4->sin_addr) == 1) {
     addr4->sin_family = GRPC_AF_INET;
diff --git a/src/python/grpcio/grpc/_cython/.gitignore b/src/python/grpcio/grpc/_cython/.gitignore
index 306e3ad277..b9936e932c 100644
--- a/src/python/grpcio/grpc/_cython/.gitignore
+++ b/src/python/grpcio/grpc/_cython/.gitignore
@@ -1,4 +1,4 @@
-cygrpc.c
+cygrpc.cpp
 *.a
 *.so
 *.dll
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/grpc_gevent.pxd b/src/python/grpcio/grpc/_cython/_cygrpc/grpc_gevent.pxd
new file mode 100644
index 0000000000..f35aebadde
--- /dev/null
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/grpc_gevent.pxd
@@ -0,0 +1,154 @@
+# Copyright 2017 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# distutils: language=c++
+
+from libc.stdint cimport uint32_t
+
+cdef extern from "grpc/impl/codegen/slice.h":
+  struct grpc_slice_buffer:
+    int count
+
+cdef extern from "src/core/lib/iomgr/error.h":
+  struct grpc_error:
+    pass
+
+cdef extern from "src/core/lib/iomgr/gevent_util.h":
+  grpc_error* grpc_socket_error(char* error) 
+  char* grpc_slice_buffer_start(grpc_slice_buffer* buffer, int i)
+  int grpc_slice_buffer_length(grpc_slice_buffer* buffer, int i)
+
+cdef extern from "src/core/lib/iomgr/sockaddr.h":
+  ctypedef struct grpc_sockaddr:
+    pass
+
+cdef extern from "src/core/lib/iomgr/resolve_address.h":
+  ctypedef struct grpc_resolved_addresses:
+    size_t naddrs
+    grpc_resolved_address* addrs
+
+  ctypedef struct grpc_resolved_address:
+    char[128] addr
+    size_t len
+
+cdef extern from "src/core/lib/iomgr/resolve_address_custom.h":
+  struct grpc_custom_resolver:
+    pass
+
+  struct grpc_custom_resolver_vtable:
+    grpc_error* (*resolve)(char* host, char* port, grpc_resolved_addresses** res);
+    void (*resolve_async)(grpc_custom_resolver* resolver, char* host, char* port);
+
+  void grpc_custom_resolve_callback(grpc_custom_resolver* resolver,
+                                    grpc_resolved_addresses* result,
+                                    grpc_error* error);
+
+cdef extern from "src/core/lib/iomgr/tcp_custom.h":
+  struct grpc_custom_socket:
+    void* impl
+    # We don't care about the rest of the fields
+  ctypedef void (*grpc_custom_connect_callback)(grpc_custom_socket* socket,
+                                             grpc_error* error)
+  ctypedef void (*grpc_custom_write_callback)(grpc_custom_socket* socket,
+                                           grpc_error* error)
+  ctypedef void (*grpc_custom_read_callback)(grpc_custom_socket* socket,
+                                          size_t nread, grpc_error* error)
+  ctypedef void (*grpc_custom_accept_callback)(grpc_custom_socket* socket,
+                                            grpc_custom_socket* client,
+                                            grpc_error* error)
+  ctypedef void (*grpc_custom_close_callback)(grpc_custom_socket* socket)
+
+  struct grpc_socket_vtable:
+      grpc_error* (*init)(grpc_custom_socket* socket, int domain);
+      void (*connect)(grpc_custom_socket* socket, const grpc_sockaddr* addr,
+                      size_t len, grpc_custom_connect_callback cb);
+      void (*destroy)(grpc_custom_socket* socket);
+      void (*shutdown)(grpc_custom_socket* socket);
+      void (*close)(grpc_custom_socket* socket, grpc_custom_close_callback cb);
+      void (*write)(grpc_custom_socket* socket, grpc_slice_buffer* slices,
+                    grpc_custom_write_callback cb);
+      void (*read)(grpc_custom_socket* socket, char* buffer, size_t length,
+                   grpc_custom_read_callback cb);
+      grpc_error* (*getpeername)(grpc_custom_socket* socket,
+                                 const grpc_sockaddr* addr, int* len);
+      grpc_error* (*getsockname)(grpc_custom_socket* socket,
+                             const grpc_sockaddr* addr, int* len);
+      grpc_error* (*setsockopt)(grpc_custom_socket* socket, int level, int optname,
+                                const void* optval, uint32_t len);
+      grpc_error* (*bind)(grpc_custom_socket* socket, const grpc_sockaddr* addr,
+                          size_t len, int flags);
+      grpc_error* (*listen)(grpc_custom_socket* socket);
+      void (*accept)(grpc_custom_socket* socket, grpc_custom_socket* client,
+                     grpc_custom_accept_callback cb);
+
+cdef extern from "src/core/lib/iomgr/timer_custom.h":
+  struct grpc_custom_timer:
+    void* timer
+    int timeout_ms
+     # We don't care about the rest of the fields
+
+  struct grpc_custom_timer_vtable:
+    void (*start)(grpc_custom_timer* t);
+    void (*stop)(grpc_custom_timer* t);
+
+  void grpc_custom_timer_callback(grpc_custom_timer* t, grpc_error* error);
+
+cdef extern from "src/core/lib/iomgr/pollset_custom.h":
+  struct grpc_custom_poller_vtable:
+    void (*init)()
+    void (*poll)(size_t timeout_ms)
+    void (*kick)()
+    void (*shutdown)()
+
+cdef extern from "src/core/lib/iomgr/iomgr_custom.h":
+  void grpc_custom_iomgr_init(grpc_socket_vtable* socket,
+                            grpc_custom_resolver_vtable* resolver,
+                            grpc_custom_timer_vtable* timer,
+                            grpc_custom_poller_vtable* poller);
+
+cdef extern from "src/core/lib/iomgr/sockaddr_utils.h":
+  int grpc_sockaddr_get_port(const grpc_resolved_address *addr);
+  int grpc_sockaddr_to_string(char **out, const grpc_resolved_address *addr,
+                              int normalize);
+  void grpc_string_to_sockaddr(grpc_resolved_address *out, char* addr, int port);
+  int grpc_sockaddr_set_port(const grpc_resolved_address *resolved_addr,
+                             int port)
+  const char* grpc_sockaddr_get_uri_scheme(const grpc_resolved_address* resolved_addr)
+
+
+cdef class TimerWrapper:
+
+  cdef grpc_custom_timer *c_timer
+  cdef object timer
+  cdef object event
+
+cdef class SocketWrapper:
+  cdef object sockopts
+  cdef object socket
+  cdef object closed
+  cdef grpc_custom_socket *c_socket
+  cdef char* c_buffer
+  cdef size_t len
+  cdef grpc_custom_socket *accepting_socket
+
+  cdef grpc_custom_connect_callback connect_cb
+  cdef grpc_custom_write_callback write_cb
+  cdef grpc_custom_read_callback read_cb
+  cdef grpc_custom_accept_callback accept_cb
+  cdef grpc_custom_close_callback close_cb
+
+
+cdef class ResolveWrapper:
+  cdef grpc_custom_resolver *c_resolver
+  cdef char* c_host
+  cdef char* c_port
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/grpc_gevent.pyx b/src/python/grpcio/grpc/_cython/_cygrpc/grpc_gevent.pyx
new file mode 100644
index 0000000000..ba8c731891
--- /dev/null
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/grpc_gevent.pyx
@@ -0,0 +1,454 @@
+# Copyright 2018 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# distutils: language=c++
+
+cimport cpython
+from libc cimport string
+from libc.stdlib cimport malloc, free
+import errno
+gevent_g = None
+gevent_socket = None
+gevent_hub = None
+gevent_event = None
+g_event = None
+g_pool = None
+
+cdef grpc_error* grpc_error_none():
+  return <grpc_error*>0
+
+cdef grpc_error* socket_error(str syscall, str err):
+  error_str = "{} failed: {}".format(syscall, err)
+  error_bytes = str_to_bytes(error_str)
+  return grpc_socket_error(error_bytes)
+
+cdef resolved_addr_to_tuple(grpc_resolved_address* address):
+  cdef char* res_str
+  port = grpc_sockaddr_get_port(address)
+  str_len = grpc_sockaddr_to_string(&res_str, address, 0) 
+  byte_str = _decode(<bytes>res_str[:str_len])
+  if byte_str.endswith(':' + str(port)):
+    byte_str = byte_str[:(0 - len(str(port)) - 1)]
+  byte_str = byte_str.lstrip('[')
+  byte_str = byte_str.rstrip(']')
+  byte_str = '{}'.format(byte_str)
+  return byte_str, port
+
+cdef sockaddr_to_tuple(const grpc_sockaddr* address, size_t length):
+  cdef grpc_resolved_address c_addr
+  string.memcpy(<void*>c_addr.addr, <void*> address, length)
+  c_addr.len = length
+  return resolved_addr_to_tuple(&c_addr)
+
+cdef sockaddr_is_ipv4(const grpc_sockaddr* address, size_t length):
+  cdef grpc_resolved_address c_addr
+  string.memcpy(<void*>c_addr.addr, <void*> address, length)
+  c_addr.len = length
+  return grpc_sockaddr_get_uri_scheme(&c_addr) == b'ipv4'
+
+cdef grpc_resolved_addresses* tuples_to_resolvaddr(tups):
+  cdef grpc_resolved_addresses* addresses
+  tups_set = set((tup[4][0], tup[4][1]) for tup in tups)
+  addresses = <grpc_resolved_addresses*> malloc(sizeof(grpc_resolved_addresses))
+  addresses.naddrs = len(tups_set)
+  addresses.addrs = <grpc_resolved_address*> malloc(sizeof(grpc_resolved_address) * len(tups_set))
+  i = 0
+  for tup in set(tups_set):
+    hostname = str_to_bytes(tup[0])
+    grpc_string_to_sockaddr(&addresses.addrs[i], hostname, tup[1])
+    i += 1
+  return addresses
+
+def _spawn_greenlet(*args):
+  greenlet = g_pool.spawn(*args)
+
+###############################
+### socket implementation ###
+###############################
+
+cdef class SocketWrapper:
+  def __cinit__(self):
+    self.sockopts = []
+    self.socket = None
+    self.c_socket = NULL
+    self.c_buffer = NULL
+    self.len = 0
+
+cdef grpc_error* socket_init(grpc_custom_socket* socket, int domain) with gil:
+  sw = SocketWrapper()
+  sw.c_socket = socket
+  sw.sockopts = []
+  cpython.Py_INCREF(sw)
+  # Python doesn't support AF_UNSPEC sockets, so we defer creation until
+  # bind/connect when we know what type of socket we need
+  sw.socket = None
+  sw.closed = False
+  sw.accepting_socket = NULL
+  socket.impl = <void*>sw
+  return grpc_error_none()
+
+cdef socket_connect_async_cython(SocketWrapper socket_wrapper, addr_tuple):
+  try:
+    socket_wrapper.socket.connect(addr_tuple)
+    socket_wrapper.connect_cb(<grpc_custom_socket*>socket_wrapper.c_socket,
+                              grpc_error_none())
+  except IOError as io_error:
+    socket_wrapper.connect_cb(<grpc_custom_socket*>socket_wrapper.c_socket,
+                              socket_error("connect", str(io_error)))
+  g_event.set()
+
+def socket_connect_async(socket_wrapper, addr_tuple):
+  socket_connect_async_cython(socket_wrapper, addr_tuple)
+
+cdef void socket_connect(grpc_custom_socket* socket, const grpc_sockaddr* addr,
+                         size_t addr_len,
+                         grpc_custom_connect_callback cb) with gil:
+  py_socket = None
+  socket_wrapper = <SocketWrapper>socket.impl
+  socket_wrapper.connect_cb = cb
+  addr_tuple = sockaddr_to_tuple(addr, addr_len)
+  if sockaddr_is_ipv4(addr, addr_len):
+      py_socket = gevent_socket.socket(gevent_socket.AF_INET)
+  else:
+      py_socket = gevent_socket.socket(gevent_socket.AF_INET6)
+  applysockopts(py_socket)
+  socket_wrapper.socket = py_socket
+  _spawn_greenlet(socket_connect_async, socket_wrapper, addr_tuple)
+
+cdef void socket_destroy(grpc_custom_socket* socket) with gil:
+  cpython.Py_DECREF(<SocketWrapper>socket.impl)
+
+cdef void socket_shutdown(grpc_custom_socket* socket) with gil:
+  try:
+    (<SocketWrapper>socket.impl).socket.shutdown(gevent_socket.SHUT_RDWR)
+  except IOError as io_error:
+    if io_error.errno != errno.ENOTCONN:
+      raise io_error
+
+cdef void socket_close(grpc_custom_socket* socket,
+                       grpc_custom_close_callback cb) with gil:
+  socket_wrapper = (<SocketWrapper>socket.impl)
+  if socket_wrapper.socket is not None:
+    socket_wrapper.socket.close()
+    socket_wrapper.closed = True
+    socket_wrapper.close_cb = cb
+    # Delay the close callback until the accept() call has picked it up
+    if socket_wrapper.accepting_socket != NULL:
+      return
+  socket_wrapper.close_cb(socket)
+
+def socket_sendmsg(socket, write_bytes):
+  try:
+    return socket.sendmsg(write_bytes)
+  except AttributeError:
+    # sendmsg not available on all Pythons/Platforms
+    return socket.send(b''.join(write_bytes))
+
+cdef socket_write_async_cython(SocketWrapper socket_wrapper, write_bytes):
+  try:
+    while write_bytes:
+      sent_byte_count = socket_sendmsg(socket_wrapper.socket, write_bytes)
+      while sent_byte_count > 0:
+        if sent_byte_count < len(write_bytes[0]):
+          write_bytes[0] = write_bytes[0][sent_byte_count:]
+          sent_byte_count = 0
+        else:
+          sent_byte_count -= len(write_bytes[0])
+          write_bytes = write_bytes[1:]
+    socket_wrapper.write_cb(<grpc_custom_socket*>socket_wrapper.c_socket,
+                            grpc_error_none())
+  except IOError as io_error:
+    socket_wrapper.write_cb(<grpc_custom_socket*>socket_wrapper.c_socket,
+                            socket_error("send", str(io_error)))
+  g_event.set()
+
+def socket_write_async(socket_wrapper, write_bytes):
+  socket_write_async_cython(socket_wrapper, write_bytes)
+
+cdef void socket_write(grpc_custom_socket* socket, grpc_slice_buffer* buffer,
+                       grpc_custom_write_callback cb) with gil:
+  cdef char* start
+  sw = <SocketWrapper>socket.impl
+  sw.write_cb = cb
+  write_bytes = []
+  for i in range(buffer.count):
+    start = grpc_slice_buffer_start(buffer, i)
+    length = grpc_slice_buffer_length(buffer, i)
+    write_bytes.append(<bytes>start[:length])
+  _spawn_greenlet(socket_write_async, <SocketWrapper>socket.impl, write_bytes)
+
+cdef socket_read_async_cython(SocketWrapper socket_wrapper):
+  cdef char* buff_char_arr
+  try:
+    buff_str = socket_wrapper.socket.recv(socket_wrapper.len)
+    buff_char_arr = buff_str
+    string.memcpy(<void*>socket_wrapper.c_buffer, buff_char_arr, len(buff_str))
+    socket_wrapper.read_cb(<grpc_custom_socket*>socket_wrapper.c_socket,
+                           len(buff_str), grpc_error_none())
+  except IOError as io_error:
+    socket_wrapper.read_cb(<grpc_custom_socket*>socket_wrapper.c_socket,
+                           -1, socket_error("recv", str(io_error)))
+  g_event.set()
+
+def socket_read_async(socket_wrapper):
+  socket_read_async_cython(socket_wrapper)
+
+cdef void socket_read(grpc_custom_socket* socket, char* buffer,
+                      size_t length, grpc_custom_read_callback cb) with gil:
+  sw = <SocketWrapper>socket.impl
+  sw.read_cb = cb
+  sw.c_buffer = buffer
+  sw.len = length
+  _spawn_greenlet(socket_read_async, sw)
+
+cdef grpc_error* socket_getpeername(grpc_custom_socket* socket,
+                                    const grpc_sockaddr* addr,
+                                    int* length) with gil:
+  cdef char* src_buf
+  peer = (<SocketWrapper>socket.impl).socket.getpeername()
+
+  cdef grpc_resolved_address c_addr
+  hostname = str_to_bytes(peer[0])
+  grpc_string_to_sockaddr(&c_addr, hostname, peer[1])
+  string.memcpy(<void*>addr, <void*>c_addr.addr, c_addr.len)
+  length[0] = c_addr.len
+  return grpc_error_none()  
+
+cdef grpc_error* socket_getsockname(grpc_custom_socket* socket,
+                                    const grpc_sockaddr* addr,
+                                    int* length) with gil:
+  cdef char* src_buf
+  cdef grpc_resolved_address c_addr
+  if (<SocketWrapper>socket.impl).socket is None:
+    peer = ('0.0.0.0', 0)
+  else:
+    peer = (<SocketWrapper>socket.impl).socket.getsockname()
+  hostname = str_to_bytes(peer[0])
+  grpc_string_to_sockaddr(&c_addr, hostname, peer[1])
+  string.memcpy(<void*>addr, <void*>c_addr.addr, c_addr.len)
+  length[0] = c_addr.len
+  return grpc_error_none()
+
+cdef grpc_error* socket_setsockopt(grpc_custom_socket* socket, int level, int optname,
+                const void *optval, uint32_t optlen) with gil:
+  # No-op; we provide a default set of options
+  return grpc_error_none()
+
+def applysockopts(s):
+  s.setsockopt(gevent_socket.SOL_SOCKET, gevent_socket.SO_REUSEADDR, 1)
+  s.setsockopt(gevent_socket.IPPROTO_TCP, gevent_socket.TCP_NODELAY, True)
+
+cdef grpc_error* socket_bind(grpc_custom_socket* socket,
+                             const grpc_sockaddr* addr,
+                             size_t len, int flags) with gil:
+  addr_tuple = sockaddr_to_tuple(addr, len)
+  try:
+    try:
+      py_socket = gevent_socket.socket(gevent_socket.AF_INET)
+      applysockopts(py_socket)
+      py_socket.bind(addr_tuple)
+    except gevent_socket.gaierror as e:
+      py_socket = gevent_socket.socket(gevent_socket.AF_INET6)
+      applysockopts(py_socket)
+      py_socket.bind(addr_tuple)
+    (<SocketWrapper>socket.impl).socket = py_socket
+  except IOError as io_error:
+    return socket_error("bind", str(io_error))
+  else:
+    return grpc_error_none()
+
+cdef grpc_error* socket_listen(grpc_custom_socket* socket) with gil:
+  (<SocketWrapper>socket.impl).socket.listen(50)
+  return grpc_error_none()
+
+cdef void accept_callback_cython(SocketWrapper s):
+   try:
+     conn, address = s.socket.accept()
+     sw = SocketWrapper()
+     sw.closed = False
+     sw.c_socket = s.accepting_socket
+     sw.sockopts = []
+     sw.socket = conn
+     sw.c_socket.impl = <void*>sw
+     sw.accepting_socket = NULL
+     cpython.Py_INCREF(sw)
+     s.accepting_socket = NULL
+     s.accept_cb(<grpc_custom_socket*>s.c_socket, sw.c_socket, grpc_error_none())
+   except IOError as io_error:
+      #TODO actual error
+      s.accepting_socket = NULL
+      s.accept_cb(<grpc_custom_socket*>s.c_socket, s.accepting_socket,
+                  socket_error("accept", str(io_error)))
+      if s.closed:
+        s.close_cb(<grpc_custom_socket*>s.c_socket)
+   g_event.set()
+
+def socket_accept_async(s):
+  accept_callback_cython(s)
+
+cdef void socket_accept(grpc_custom_socket* socket, grpc_custom_socket* client,
+                        grpc_custom_accept_callback cb) with gil:
+  sw = <SocketWrapper>socket.impl
+  sw.accepting_socket = client
+  sw.accept_cb = cb
+  _spawn_greenlet(socket_accept_async, sw)
+
+#####################################
+######Resolver implementation #######
+#####################################
+
+cdef class ResolveWrapper:
+  def __cinit__(self):
+    self.c_resolver = NULL
+    self.c_host = NULL
+    self.c_port = NULL
+
+cdef socket_resolve_async_cython(ResolveWrapper resolve_wrapper):
+  try:
+    res = gevent_socket.getaddrinfo(resolve_wrapper.c_host, resolve_wrapper.c_port)
+    grpc_custom_resolve_callback(<grpc_custom_resolver*>resolve_wrapper.c_resolver,
+                                 tuples_to_resolvaddr(res), grpc_error_none())
+  except IOError as io_error:
+    grpc_custom_resolve_callback(<grpc_custom_resolver*>resolve_wrapper.c_resolver,
+                                 <grpc_resolved_addresses*>0,
+                                 socket_error("getaddrinfo", str(io_error)))
+  g_event.set()
+
+def socket_resolve_async_python(resolve_wrapper):
+  socket_resolve_async_cython(resolve_wrapper)
+
+cdef void socket_resolve_async(grpc_custom_resolver* r, char* host, char* port) with gil:
+  rw = ResolveWrapper()
+  rw.c_resolver = r
+  rw.c_host = host
+  rw.c_port = port
+  _spawn_greenlet(socket_resolve_async_python, rw)
+
+cdef grpc_error* socket_resolve(char* host, char* port,
+                                grpc_resolved_addresses** res) with gil:
+    try:
+      result = gevent_socket.getaddrinfo(host, port)
+      res[0] = tuples_to_resolvaddr(result)
+      return grpc_error_none()
+    except IOError as io_error:
+      return socket_error("getaddrinfo", str(io_error))
+
+###############################
+### timer implementation ######
+###############################
+
+cdef class TimerWrapper:
+  def __cinit__(self, deadline):
+    self.timer = gevent_hub.get_hub().loop.timer(deadline)
+    self.event = None
+
+  def start(self):
+    self.event = gevent_event.Event()
+    self.timer.start(self.on_finish)
+
+  def on_finish(self):
+    grpc_custom_timer_callback(self.c_timer, grpc_error_none())
+    self.timer.stop()
+    g_event.set()
+
+  def stop(self):
+    self.event.set()
+    self.timer.stop()
+
+cdef void timer_start(grpc_custom_timer* t) with gil:
+  timer = TimerWrapper(t.timeout_ms / 1000.0)
+  timer.c_timer = t
+  t.timer = <void*>timer
+  timer.start()
+
+cdef void timer_stop(grpc_custom_timer* t) with gil:
+  time_wrapper = <object>t.timer
+  time_wrapper.stop()
+
+###############################
+### pollset implementation ###
+###############################
+
+cdef void init_loop() with gil:
+  pass
+
+cdef void destroy_loop() with gil:
+  g_pool.join()
+
+cdef void kick_loop() with gil:
+  g_event.set()
+
+cdef void run_loop(size_t timeout_ms) with gil:
+    timeout = timeout_ms / 1000.0
+    if timeout_ms > 0:
+      g_event.wait(timeout)
+      g_event.clear()
+
+###############################
+### Initializer ###############
+###############################
+
+cdef grpc_socket_vtable gevent_socket_vtable
+cdef grpc_custom_resolver_vtable gevent_resolver_vtable
+cdef grpc_custom_timer_vtable gevent_timer_vtable
+cdef grpc_custom_poller_vtable gevent_pollset_vtable
+
+def init_grpc_gevent():
+  # Lazily import gevent
+  global gevent_socket
+  global gevent_g
+  global gevent_hub
+  global gevent_event
+  global g_event
+  global g_pool
+  import gevent
+  gevent_g = gevent
+  import gevent.socket
+  gevent_socket = gevent.socket
+  import gevent.hub
+  gevent_hub = gevent.hub
+  import gevent.event
+  gevent_event = gevent.event
+  import gevent.pool
+
+  g_event = gevent.event.Event()
+  g_pool = gevent.pool.Group()
+  gevent_resolver_vtable.resolve = socket_resolve
+  gevent_resolver_vtable.resolve_async = socket_resolve_async
+
+  gevent_socket_vtable.init = socket_init
+  gevent_socket_vtable.connect = socket_connect
+  gevent_socket_vtable.destroy = socket_destroy
+  gevent_socket_vtable.shutdown = socket_shutdown
+  gevent_socket_vtable.close = socket_close
+  gevent_socket_vtable.write = socket_write
+  gevent_socket_vtable.read = socket_read
+  gevent_socket_vtable.getpeername = socket_getpeername
+  gevent_socket_vtable.getsockname = socket_getsockname
+  gevent_socket_vtable.setsockopt = socket_setsockopt
+  gevent_socket_vtable.bind = socket_bind
+  gevent_socket_vtable.listen = socket_listen
+  gevent_socket_vtable.accept = socket_accept
+
+  gevent_timer_vtable.start = timer_start
+  gevent_timer_vtable.stop = timer_stop
+
+  gevent_pollset_vtable.init = init_loop
+  gevent_pollset_vtable.poll = run_loop
+  gevent_pollset_vtable.kick = kick_loop
+  gevent_pollset_vtable.shutdown = destroy_loop
+
+  grpc_custom_iomgr_init(&gevent_socket_vtable,
+                         &gevent_resolver_vtable,
+                         &gevent_timer_vtable,
+                         &gevent_pollset_vtable)
diff --git a/src/python/grpcio/grpc/_cython/cygrpc.pxd b/src/python/grpcio/grpc/_cython/cygrpc.pxd
index b6a794c6d7..c8ace7c3cc 100644
--- a/src/python/grpcio/grpc/_cython/cygrpc.pxd
+++ b/src/python/grpcio/grpc/_cython/cygrpc.pxd
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# distutils: language=c++
 
 include "_cygrpc/grpc.pxi"
 
@@ -27,3 +28,5 @@ include "_cygrpc/security.pxd.pxi"
 include "_cygrpc/server.pxd.pxi"
 include "_cygrpc/tag.pxd.pxi"
 include "_cygrpc/time.pxd.pxi"
+
+include "_cygrpc/grpc_gevent.pxd"
diff --git a/src/python/grpcio/grpc/_cython/cygrpc.pyx b/src/python/grpcio/grpc/_cython/cygrpc.pyx
index 2ee2e6b73e..f5f08fc983 100644
--- a/src/python/grpcio/grpc/_cython/cygrpc.pyx
+++ b/src/python/grpcio/grpc/_cython/cygrpc.pyx
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# distutils: language=c++
 
 cimport cpython
 
@@ -35,6 +36,8 @@ include "_cygrpc/server.pyx.pxi"
 include "_cygrpc/tag.pyx.pxi"
 include "_cygrpc/time.pyx.pxi"
 
+include "_cygrpc/grpc_gevent.pyx"
+
 #
 # initialize gRPC
 #
diff --git a/src/python/grpcio/grpc/experimental/__init__.py b/src/python/grpcio/grpc/experimental/__init__.py
new file mode 100644
index 0000000000..dcec322b69
--- /dev/null
+++ b/src/python/grpcio/grpc/experimental/__init__.py
@@ -0,0 +1,17 @@
+# Copyright 2018 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""gRPC's experimental APIs.
+
+These APIs are subject to be removed during any minor version release.
+"""
diff --git a/src/python/grpcio/grpc/experimental/gevent.py b/src/python/grpcio/grpc/experimental/gevent.py
new file mode 100644
index 0000000000..159d612b4e
--- /dev/null
+++ b/src/python/grpcio/grpc/experimental/gevent.py
@@ -0,0 +1,27 @@
+# Copyright 2018 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""gRPC's Python gEvent APIs."""
+
+from grpc._cython import cygrpc as _cygrpc
+
+
+def init_gevent():
+    """Patches gRPC's libraries to be compatible with gevent.
+
+    This must be called AFTER the python standard lib has been patched,
+    but BEFORE creating and gRPC objects.
+
+    In order for progress to be made, the application must drive the event loop.
+    """
+    _cygrpc.init_grpc_gevent()
diff --git a/src/python/grpcio_tests/commands.py b/src/python/grpcio_tests/commands.py
index 93f84572b7..d4dbcdc191 100644
--- a/src/python/grpcio_tests/commands.py
+++ b/src/python/grpcio_tests/commands.py
@@ -108,6 +108,55 @@ class TestLite(setuptools.Command):
         self.distribution.fetch_build_eggs(self.distribution.tests_require)
 
 
+class TestGevent(setuptools.Command):
+    """Command to run tests w/gevent."""
+
+    BANNED_TESTS = (
+        # These tests send a lot of RPCs and are really slow on gevent.  They will
+        # eventually succeed, but need to dig into performance issues.
+        'unit._cython._no_messages_server_completion_queue_per_call_test.Test.test_rpcs',
+        'unit._cython._no_messages_single_server_completion_queue_test.Test.test_rpcs',
+        # I have no idea why this doesn't work in gevent, but it shouldn't even be
+        # using the c-core
+        'testing._client_test.ClientTest.test_infinite_request_stream_real_time',
+        # TODO(https://github.com/grpc/grpc/issues/14789) enable this test
+        'unit._server_ssl_cert_config_test',
+        # Beta API is unsupported for gevent
+        'protoc_plugin.beta_python_plugin_test',
+        'unit.beta._beta_features_test',
+    )
+    description = 'run tests with gevent.  Assumes grpc/gevent are installed'
+    user_options = []
+
+    def initialize_options(self):
+        pass
+
+    def finalize_options(self):
+        # distutils requires this override.
+        pass
+
+    def run(self):
+        from gevent import monkey
+        monkey.patch_all()
+
+        import tests
+
+        import grpc.experimental.gevent
+        grpc.experimental.gevent.init_gevent()
+
+        import gevent
+
+        import tests
+        loader = tests.Loader()
+        loader.loadTestsFromNames(['tests'])
+        runner = tests.Runner()
+        runner.skip_tests(self.BANNED_TESTS)
+        result = gevent.spawn(runner.run, loader.suite)
+        result.join()
+        if not result.value.wasSuccessful():
+            sys.exit('Test failure')
+
+
 class RunInterop(test.test):
 
     description = 'run interop test client/server'
diff --git a/src/python/grpcio_tests/setup.py b/src/python/grpcio_tests/setup.py
index 250df65803..4e0f6726fa 100644
--- a/src/python/grpcio_tests/setup.py
+++ b/src/python/grpcio_tests/setup.py
@@ -50,7 +50,8 @@ COMMAND_CLASS = {
     'build_package_protos': grpc_tools.command.BuildPackageProtos,
     'build_py': commands.BuildPy,
     'run_interop': commands.RunInterop,
-    'test_lite': commands.TestLite
+    'test_lite': commands.TestLite,
+    'test_gevent': commands.TestGevent,
 }
 
 PACKAGE_DATA = {
diff --git a/src/python/grpcio_tests/tests/_runner.py b/src/python/grpcio_tests/tests/_runner.py
index 8e27dc6c6d..eaaa027e61 100644
--- a/src/python/grpcio_tests/tests/_runner.py
+++ b/src/python/grpcio_tests/tests/_runner.py
@@ -117,6 +117,12 @@ class AugmentedCase(collections.namedtuple('AugmentedCase', ['case', 'id'])):
 
 class Runner(object):
 
+    def __init__(self):
+        self._skipped_tests = []
+
+    def skip_tests(self, tests):
+        self._skipped_tests = tests
+
     def run(self, suite):
         """See setuptools' test_runner setup argument for information."""
         # only run test cases with id starting with given prefix
@@ -181,27 +187,31 @@ class Runner(object):
         # Run the tests
         result.startTestRun()
         for augmented_case in augmented_cases:
-            sys.stdout.write('Running       {}\n'.format(
-                augmented_case.case.id()))
-            sys.stdout.flush()
-            case_thread = threading.Thread(
-                target=augmented_case.case.run, args=(result,))
-            try:
-                with stdout_pipe, stderr_pipe:
-                    case_thread.start()
-                    while case_thread.is_alive():
-                        check_kill_self()
-                        time.sleep(0)
-                    case_thread.join()
-            except:
-                # re-raise the exception after forcing the with-block to end
-                raise
-            result.set_output(augmented_case.case, stdout_pipe.output(),
-                              stderr_pipe.output())
-            sys.stdout.write(result_out.getvalue())
-            sys.stdout.flush()
-            result_out.truncate(0)
-            check_kill_self()
+            for skipped_test in self._skipped_tests:
+                if skipped_test in augmented_case.case.id():
+                    break
+            else:
+                sys.stdout.write('Running       {}\n'.format(
+                    augmented_case.case.id()))
+                sys.stdout.flush()
+                case_thread = threading.Thread(
+                    target=augmented_case.case.run, args=(result,))
+                try:
+                    with stdout_pipe, stderr_pipe:
+                        case_thread.start()
+                        while case_thread.is_alive():
+                            check_kill_self()
+                            time.sleep(0)
+                        case_thread.join()
+                except:
+                    # re-raise the exception after forcing the with-block to end
+                    raise
+                result.set_output(augmented_case.case, stdout_pipe.output(),
+                                  stderr_pipe.output())
+                sys.stdout.write(result_out.getvalue())
+                sys.stdout.flush()
+                result_out.truncate(0)
+                check_kill_self()
         result.stopTestRun()
         stdout_pipe.close()
         stderr_pipe.close()
diff --git a/tools/run_tests/helper_scripts/build_python.sh b/tools/run_tests/helper_scripts/build_python.sh
index b809fe012f..dac29b91dd 100755
--- a/tools/run_tests/helper_scripts/build_python.sh
+++ b/tools/run_tests/helper_scripts/build_python.sh
@@ -152,6 +152,12 @@ pip_install_dir() {
   cd "$PWD"
 }
 
+case "$VENV" in
+  *gevent*)
+  $VENV_PYTHON -m pip install gevent
+  ;;
+esac
+
 $VENV_PYTHON -m pip install --upgrade pip==9.0.1
 $VENV_PYTHON -m pip install setuptools
 $VENV_PYTHON -m pip install cython
diff --git a/tools/run_tests/helper_scripts/run_python.sh b/tools/run_tests/helper_scripts/run_python.sh
index bcfe3a6577..2b7321e527 100755
--- a/tools/run_tests/helper_scripts/run_python.sh
+++ b/tools/run_tests/helper_scripts/run_python.sh
@@ -22,7 +22,7 @@ PYTHON=$(realpath "${1:-py27/bin/python}")
 
 ROOT=$(pwd)
 
-$PYTHON "$ROOT/src/python/grpcio_tests/setup.py" test_lite
+$PYTHON "$ROOT/src/python/grpcio_tests/setup.py" "$2"
 
 mkdir -p "$ROOT/reports"
 rm -rf "$ROOT/reports/python-coverage"
diff --git a/tools/run_tests/run_interop_tests.py b/tools/run_tests/run_interop_tests.py
index ba4ab3bd36..970b0d7902 100755
--- a/tools/run_tests/run_interop_tests.py
+++ b/tools/run_tests/run_interop_tests.py
@@ -545,13 +545,13 @@ class PythonLanguage:
 
     def client_cmd(self, args):
         return [
-            'py27/bin/python', 'src/python/grpcio_tests/setup.py',
+            'py27_native/bin/python', 'src/python/grpcio_tests/setup.py',
             'run_interop', '--client', '--args="{}"'.format(' '.join(args))
         ]
 
     def client_cmd_http2interop(self, args):
         return [
-            'py27/bin/python',
+            'py27_native/bin/python',
             'src/python/grpcio_tests/tests/http2/negative_http2_client.py',
         ] + args
 
@@ -560,7 +560,7 @@ class PythonLanguage:
 
     def server_cmd(self, args):
         return [
-            'py27/bin/python', 'src/python/grpcio_tests/setup.py',
+            'py27_native/bin/python', 'src/python/grpcio_tests/setup.py',
             'run_interop', '--server', '--args="{}"'.format(' '.join(args))
         ]
 
diff --git a/tools/run_tests/run_tests.py b/tools/run_tests/run_tests.py
index 85c7f5c4dc..4146eec42d 100755
--- a/tools/run_tests/run_tests.py
+++ b/tools/run_tests/run_tests.py
@@ -204,19 +204,28 @@ def _is_use_docker_child():
 
 
 _PythonConfigVars = collections.namedtuple('_ConfigVars', [
-    'shell', 'builder', 'builder_prefix_arguments', 'venv_relative_python',
-    'toolchain', 'runner'
+    'shell',
+    'builder',
+    'builder_prefix_arguments',
+    'venv_relative_python',
+    'toolchain',
+    'runner',
+    'test_name',
+    'iomgr_platform',
 ])
 
 
 def _python_config_generator(name, major, minor, bits, config_vars):
+    name += '_' + config_vars.iomgr_platform
     return PythonConfig(
         name, config_vars.shell + config_vars.builder +
         config_vars.builder_prefix_arguments + [
             _python_pattern_function(major=major, minor=minor, bits=bits)
         ] + [name] + config_vars.venv_relative_python + config_vars.toolchain,
-        config_vars.shell + config_vars.runner +
-        [os.path.join(name, config_vars.venv_relative_python[0])])
+        config_vars.shell + config_vars.runner + [
+            os.path.join(name, config_vars.venv_relative_python[0]),
+            config_vars.test_name
+        ])
 
 
 def _pypy_config_generator(name, major, config_vars):
@@ -281,7 +290,7 @@ class CLanguage(object):
             self._docker_distro, self._make_options = self._compiler_options(
                 self.args.use_docker, self.args.compiler)
         if args.iomgr_platform == "uv":
-            cflags = '-DGRPC_UV -DGRPC_CUSTOM_IOMGR_THREAD_CHECK '
+            cflags = '-DGRPC_UV -DGRPC_CUSTOM_IOMGR_THREAD_CHECK -DGRPC_CUSTOM_SOCKET '
             try:
                 cflags += subprocess.check_output(
                     ['pkg-config', '--cflags', 'libuv']).strip() + ' '
@@ -770,12 +779,16 @@ class PythonLanguage(object):
             venv_relative_python = ['bin/python']
             toolchain = ['unix']
 
+        test_command = 'test_lite'
+        if args.iomgr_platform == 'gevent':
+            test_command = 'test_gevent'
         runner = [
             os.path.abspath('tools/run_tests/helper_scripts/run_python.sh')
         ]
-        config_vars = _PythonConfigVars(shell, builder,
-                                        builder_prefix_arguments,
-                                        venv_relative_python, toolchain, runner)
+
+        config_vars = _PythonConfigVars(
+            shell, builder, builder_prefix_arguments, venv_relative_python,
+            toolchain, runner, test_command, args.iomgr_platform)
         python27_config = _python_config_generator(
             name='py27',
             major='2',
@@ -1341,7 +1354,7 @@ argp.add_argument(
 )
 argp.add_argument(
     '--iomgr_platform',
-    choices=['native', 'uv'],
+    choices=['native', 'uv', 'gevent'],
     default='native',
     help='Selects iomgr platform to build on')
 argp.add_argument(
diff --git a/tools/run_tests/run_tests_matrix.py b/tools/run_tests/run_tests_matrix.py
index 1c99e794a9..e43319beba 100755
--- a/tools/run_tests/run_tests_matrix.py
+++ b/tools/run_tests/run_tests_matrix.py
@@ -114,7 +114,7 @@ def _workspace_jobspec(name,
 def _generate_jobs(languages,
                    configs,
                    platforms,
-                   iomgr_platform='native',
+                   iomgr_platforms=['native'],
                    arch=None,
                    compiler=None,
                    labels=[],
@@ -125,40 +125,43 @@ def _generate_jobs(languages,
     result = []
     for language in languages:
         for platform in platforms:
-            for config in configs:
-                name = '%s_%s_%s_%s' % (language, platform, config,
-                                        iomgr_platform)
-                runtests_args = [
-                    '-l', language, '-c', config, '--iomgr_platform',
-                    iomgr_platform
-                ]
-                if arch or compiler:
-                    name += '_%s_%s' % (arch, compiler)
-                    runtests_args += ['--arch', arch, '--compiler', compiler]
-                if '--build_only' in extra_args:
-                    name += '_buildonly'
-                for extra_env in extra_envs:
-                    name += '_%s_%s' % (extra_env, extra_envs[extra_env])
-
-                runtests_args += extra_args
-                if platform == 'linux':
-                    job = _docker_jobspec(
-                        name=name,
-                        runtests_args=runtests_args,
-                        runtests_envs=extra_envs,
-                        inner_jobs=inner_jobs,
-                        timeout_seconds=timeout_seconds)
-                else:
-                    job = _workspace_jobspec(
-                        name=name,
-                        runtests_args=runtests_args,
-                        runtests_envs=extra_envs,
-                        inner_jobs=inner_jobs,
-                        timeout_seconds=timeout_seconds)
-
-                job.labels = [platform, config, language, iomgr_platform
-                             ] + labels
-                result.append(job)
+            for iomgr_platform in iomgr_platforms:
+                for config in configs:
+                    name = '%s_%s_%s_%s' % (language, platform, config,
+                                            iomgr_platform)
+                    runtests_args = [
+                        '-l', language, '-c', config, '--iomgr_platform',
+                        iomgr_platform
+                    ]
+                    if arch or compiler:
+                        name += '_%s_%s' % (arch, compiler)
+                        runtests_args += [
+                            '--arch', arch, '--compiler', compiler
+                        ]
+                    if '--build_only' in extra_args:
+                        name += '_buildonly'
+                    for extra_env in extra_envs:
+                        name += '_%s_%s' % (extra_env, extra_envs[extra_env])
+
+                    runtests_args += extra_args
+                    if platform == 'linux':
+                        job = _docker_jobspec(
+                            name=name,
+                            runtests_args=runtests_args,
+                            runtests_envs=extra_envs,
+                            inner_jobs=inner_jobs,
+                            timeout_seconds=timeout_seconds)
+                    else:
+                        job = _workspace_jobspec(
+                            name=name,
+                            runtests_args=runtests_args,
+                            runtests_envs=extra_envs,
+                            inner_jobs=inner_jobs,
+                            timeout_seconds=timeout_seconds)
+
+                    job.labels = [platform, config, language, iomgr_platform
+                                 ] + labels
+                    result.append(job)
     return result
 
 
@@ -184,13 +187,22 @@ def _create_test_jobs(extra_args=[], inner_jobs=_DEFAULT_INNER_JOBS):
         timeout_seconds=_CPP_RUNTESTS_TIMEOUT)
 
     test_jobs += _generate_jobs(
-        languages=['csharp', 'python'],
+        languages=['csharp'],
         configs=['dbg', 'opt'],
         platforms=['linux', 'macos', 'windows'],
         labels=['basictests', 'multilang'],
         extra_args=extra_args,
         inner_jobs=inner_jobs)
 
+    test_jobs += _generate_jobs(
+        languages=['python'],
+        configs=['opt'],
+        platforms=['linux', 'macos', 'windows'],
+        iomgr_platforms=['native', 'gevent'],
+        labels=['basictests', 'multilang'],
+        extra_args=extra_args,
+        inner_jobs=inner_jobs)
+
     # supported on linux and mac.
     test_jobs += _generate_jobs(
         languages=['c++'],
@@ -377,7 +389,7 @@ def _create_portability_test_jobs(extra_args=[],
         languages=['c'],
         configs=['dbg'],
         platforms=['linux'],
-        iomgr_platform='uv',
+        iomgr_platforms=['uv'],
         labels=['portability', 'corelang'],
         extra_args=extra_args,
         inner_jobs=inner_jobs,