Initial checkin of gRPC to third_party/

third_party/grpc/src/core/support/cpu_posix.c

Index: third_party/grpc/src/core/support/cpu_posix.c
diff --git a/third_party/WebKit/Source/build/win/Precompile.h b/third_party/grpc/src/core/support/cpu_posix.c
similarity index 56%
copy from third_party/WebKit/Source/build/win/Precompile.h
copy to third_party/grpc/src/core/support/cpu_posix.c
index 8a0ff29c353fc1d30c92d27f369d7c422a579bc8..8f01c284ca425ccab9d7f10ac63cbc029f0bfc7f 100644
--- a/third_party/WebKit/Source/build/win/Precompile.h
+++ b/third_party/grpc/src/core/support/cpu_posix.c
@@ -1,5 +1,7 @@
 /*
- * Copyright (C) 2012 Google Inc. All rights reserved.
+ *
+ * Copyright 2015-2016, Google Inc.
+ * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
@@ -26,43 +28,50 @@
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-/*
- * Precompiled header for WebKit when built on Windows using
- * GYP-generated project files.  Not used by other build
- * configurations.
  *
- * Using precompiled headers speeds the build up significantly.  On a
- * fast machine (HP Z600, 12 GB of RAM), an ~18% decrease in full
- * build time was measured.
  */
 
-#if defined(WinPrecompile_h_)
-#error You shouldn't include the precompiled header file more than once.
-#endif
+#include <grpc/support/port_platform.h>
 
-#define WinPrecompile_h_
-
-#define _USE_MATH_DEFINES // Make math.h behave like other platforms.
-
-#include <Windows.h>
+#ifdef GPR_CPU_POSIX
 
 #include <errno.h>
-#include <fcntl.h>
-#include <limits.h>
-#include <math.h>
-#include <stdarg.h>
-#include <stddef.h>
-#include <stdio.h>
-#include <stdlib.h>
+#include <unistd.h>
 #include <string.h>
-#include <time.h>
 
-#include <algorithm>
-#include <ciso646>
-#include <cmath>
-#include <cstddef>
-#include <limits>
-#include <string>
-#include <utility>
+#include <grpc/support/log.h>
+#include <grpc/support/sync.h>
+
+static __thread char magic_thread_local;
+
+static long ncpus = 0;
+
+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;
+}
+
+/* This is a cheap, but good enough, pointer hash for sharding things: */
+static size_t shard_ptr(const void *info) {
+  size_t x = (size_t)info;
+  return ((x >> 4) ^ (x >> 9) ^ (x >> 14)) % gpr_cpu_num_cores();
+}
+
+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 */
+  return (unsigned)shard_ptr(&magic_thread_local);
+}
+
+#endif /* GPR_CPU_POSIX */