1 files changed, 78 insertions, 0 deletions
diff --git a/src/core/lib/gpr/cpu_linux.cc b/src/core/lib/gpr/cpu_linux.cc
new file mode 100644
index 0000000000..21b1a71dc9
--- /dev/null
+++ b/src/core/lib/gpr/cpu_linux.cc
@@ -0,0 +1,78 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif /* _GNU_SOURCE */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_CPU_LINUX
+
+#include <errno.h>
+#include <sched.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <grpc/support/cpu.h>
+#include <grpc/support/log.h>
+#include <grpc/support/sync.h>
+
+static int ncpus = 0;
+
+static void init_num_cpus() {
+#ifndef GPR_MUSL_LIBC_COMPAT
+  if (sched_getcpu() < 0) {
+    gpr_log(GPR_ERROR, "Error determining current CPU: %s\n", strerror(errno));
+    ncpus = 1;
+    return;
+  }
+#endif
+  /* This must be signed. sysconf returns -1 when the number cannot be
+     determined */
+  ncpus = (int)sysconf(_SC_NPROCESSORS_ONLN);
+  if (ncpus < 1) {
+    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_num_cpus);
+  return (unsigned)ncpus;
+}
+
+unsigned gpr_cpu_current_cpu(void) {
+#ifdef GPR_MUSL_LIBC_COMPAT
+  // sched_getcpu() is undefined on musl
+  return 0;
+#else
+  if (gpr_cpu_num_cores() == 1) {
+    return 0;
+  }
+  int cpu = sched_getcpu();
+  if (cpu < 0) {
+    gpr_log(GPR_ERROR, "Error determining current CPU: %s\n", strerror(errno));
+    return 0;
+  }
+  return (unsigned)cpu;
+#endif
+}
+
+#endif /* GPR_CPU_LINUX */