| /* |
| * |
| * 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 = static_cast<int>(sysconf(_SC_NPROCESSORS_CONF)); |
| 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 static_cast<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; |
| } |
| if (static_cast<unsigned>(cpu) >= gpr_cpu_num_cores()) { |
| gpr_log(GPR_ERROR, "Cannot handle hot-plugged CPUs"); |
| return 0; |
| } |
| return static_cast<unsigned>(cpu); |
| #endif |
| } |
| |
| #endif /* GPR_CPU_LINUX */ |