1.1 --- a/src/os/linux/vm/os_linux.cpp Tue Jan 03 08:51:36 2017 -0800
1.2 +++ b/src/os/linux/vm/os_linux.cpp Thu Sep 22 02:04:40 2016 -0700
1.3 @@ -1,5 +1,5 @@
1.4 /*
1.5 - * Copyright (c) 1999, 2015, Oracle and/or its affiliates. All rights reserved.
1.6 + * Copyright (c) 1999, 2016, Oracle and/or its affiliates. All rights reserved.
1.7 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.8 *
1.9 * This code is free software; you can redistribute it and/or modify it
1.10 @@ -104,6 +104,14 @@
1.11
1.12 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
1.13
1.14 +#ifndef _GNU_SOURCE
1.15 + #define _GNU_SOURCE
1.16 + #include <sched.h>
1.17 + #undef _GNU_SOURCE
1.18 +#else
1.19 + #include <sched.h>
1.20 +#endif
1.21 +
1.22 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling
1.23 // getrusage() is prepared to handle the associated failure.
1.24 #ifndef RUSAGE_THREAD
1.25 @@ -5016,12 +5024,42 @@
1.26 }
1.27 };
1.28
1.29 +static int os_cpu_count(const cpu_set_t* cpus) {
1.30 + int count = 0;
1.31 + // only look up to the number of configured processors
1.32 + for (int i = 0; i < os::processor_count(); i++) {
1.33 + if (CPU_ISSET(i, cpus)) {
1.34 + count++;
1.35 + }
1.36 + }
1.37 + return count;
1.38 +}
1.39 +
1.40 +// Get the current number of available processors for this process.
1.41 +// This value can change at any time during a process's lifetime.
1.42 +// sched_getaffinity gives an accurate answer as it accounts for cpusets.
1.43 +// If anything goes wrong we fallback to returning the number of online
1.44 +// processors - which can be greater than the number available to the process.
1.45 int os::active_processor_count() {
1.46 - // Linux doesn't yet have a (official) notion of processor sets,
1.47 - // so just return the number of online processors.
1.48 - int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
1.49 - assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check");
1.50 - return online_cpus;
1.51 + cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors
1.52 + int cpus_size = sizeof(cpu_set_t);
1.53 + int cpu_count = 0;
1.54 +
1.55 + // pid 0 means the current thread - which we have to assume represents the process
1.56 + if (sched_getaffinity(0, cpus_size, &cpus) == 0) {
1.57 + cpu_count = os_cpu_count(&cpus);
1.58 + if (PrintActiveCpus) {
1.59 + tty->print_cr("active_processor_count: sched_getaffinity processor count: %d", cpu_count);
1.60 + }
1.61 + }
1.62 + else {
1.63 + cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN);
1.64 + warning("sched_getaffinity failed (%s)- using online processor count (%d) "
1.65 + "which may exceed available processors", strerror(errno), cpu_count);
1.66 + }
1.67 +
1.68 + assert(cpu_count > 0 && cpu_count <= processor_count(), "sanity check");
1.69 + return cpu_count;
1.70 }
1.71
1.72 void os::set_native_thread_name(const char *name) {
