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//
//
// 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/cpu.h>
#include <grpc/support/log.h>
#include <grpc/support/sync.h>
#include "src/core/lib/gpr/useful.h"
#include "src/core/lib/gprpp/crash.h"
static long ncpus = 0;
static pthread_key_t thread_id_key;
static void init_ncpus() {
ncpus = sysconf(_SC_NPROCESSORS_CONF);
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) {
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) {
// Note we cannot use gpr_malloc here because this allocation can happen in
// a main thread and will only be free'd when the main thread exits, which
// will cause our internal memory counters to believe it is a leak.
thread_id = static_cast<unsigned int*>(malloc(sizeof(unsigned int)));
pthread_setspecific(thread_id_key, thread_id);
}
return (unsigned)grpc_core::HashPointer(thread_id, gpr_cpu_num_cores());
}
#endif // GPR_CPU_POSIX
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