1 files changed, 80 insertions, 0 deletions
diff --git a/src/core/lib/gpr/cpu_posix.cc b/src/core/lib/gpr/cpu_posix.cc
new file mode 100644
index 0000000000..bca14a0c12
--- /dev/null
+++ b/src/core/lib/gpr/cpu_posix.cc
@@ -0,0 +1,80 @@
+/*
+ *
+ * Copyright 2015 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.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#if defined(GPR_CPU_POSIX)
+
+#include <errno.h>
+#include <pthread.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/cpu.h>
+#include <grpc/support/log.h>
+#include <grpc/support/sync.h>
+#include <grpc/support/useful.h>
+
+static long ncpus = 0;
+
+static pthread_key_t thread_id_key;
+
+static void init_ncpus() {
+  ncpus = sysconf(_SC_NPROCESSORS_ONLN);
+  if (ncpus < 1 || ncpus > INT32_MAX) {
+    gpr_log(GPR_ERROR, "Cannot determine number of CPUs: assuming 1");
+    ncpus = 1;
+  }
+}
+
+unsigned gpr_cpu_num_cores(void) {
+  static gpr_once once = GPR_ONCE_INIT;
+  gpr_once_init(&once, init_ncpus);
+  return (unsigned)ncpus;
+}
+
+static void delete_thread_id(void* value) {
+  if (value) {
+    gpr_free(value);
+  }
+}
+
+static void init_thread_id_key(void) {
+  pthread_key_create(&thread_id_key, delete_thread_id);
+}
+
+unsigned gpr_cpu_current_cpu(void) {
+  /* NOTE: there's no way I know to return the actual cpu index portably...
+     most code that's using this is using it to shard across work queues though,
+     so here we use thread identity instead to achieve a similar though not
+     identical effect */
+  static gpr_once once = GPR_ONCE_INIT;
+  gpr_once_init(&once, init_thread_id_key);
+
+  unsigned int* thread_id =
+      static_cast<unsigned int*>(pthread_getspecific(thread_id_key));
+  if (thread_id == nullptr) {
+    thread_id = static_cast<unsigned int*>(gpr_malloc(sizeof(unsigned int)));
+    pthread_setspecific(thread_id_key, thread_id);
+  }
+
+  return (unsigned)GPR_HASH_POINTER(thread_id, gpr_cpu_num_cores());
+}
+
+#endif /* GPR_CPU_POSIX */