diff options
Diffstat (limited to 'src/core/lib/support/cpu_posix.cc')
-rw-r--r-- | src/core/lib/support/cpu_posix.cc | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/src/core/lib/support/cpu_posix.cc b/src/core/lib/support/cpu_posix.cc new file mode 100644 index 0000000000..503a96b4c8 --- /dev/null +++ b/src/core/lib/support/cpu_posix.cc @@ -0,0 +1,58 @@ +/* + * + * 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> + +#ifdef GPR_CPU_POSIX + +#include <errno.h> +#include <string.h> +#include <unistd.h> + +#include <grpc/support/cpu.h> +#include <grpc/support/log.h> +#include <grpc/support/sync.h> +#include <grpc/support/useful.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; +} + +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)GPR_HASH_POINTER(&magic_thread_local, gpr_cpu_num_cores()); +} + +#endif /* GPR_CPU_POSIX */ |