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e7f5f48d68
Fun fact: these files used to be called log.[ch] until we ran into conflicts with systems having a log.h file. But now that we always include "lib/log/log.h", we should be fine.
99 lines
2.6 KiB
C
99 lines
2.6 KiB
C
/* Copyright (c) 2003-2004, Roger Dingledine
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* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
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* Copyright (c) 2007-2018, The Tor Project, Inc. */
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/* See LICENSE for licensing information */
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/**
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* \file numcpus.c
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* \brief Compute the number of CPUs configured on this system.
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**/
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#include "orconfig.h"
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#include "lib/thread/numcpus.h"
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#include "lib/log/log.h"
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#include "lib/log/util_bug.h"
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#ifdef _WIN32
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#include <windows.h>
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#endif
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#include <stdlib.h>
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/** Implementation logic for compute_num_cpus(). */
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static int
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compute_num_cpus_impl(void)
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{
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#ifdef _WIN32
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SYSTEM_INFO info;
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memset(&info, 0, sizeof(info));
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GetSystemInfo(&info);
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if (info.dwNumberOfProcessors >= 1 && info.dwNumberOfProcessors < INT_MAX)
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return (int)info.dwNumberOfProcessors;
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else
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return -1;
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#elif defined(HAVE_SYSCONF)
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#ifdef _SC_NPROCESSORS_CONF
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long cpus_conf = sysconf(_SC_NPROCESSORS_CONF);
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#else
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long cpus_conf = -1;
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#endif
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#ifdef _SC_NPROCESSORS_ONLN
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long cpus_onln = sysconf(_SC_NPROCESSORS_ONLN);
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#else
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long cpus_onln = -1;
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#endif
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long cpus = -1;
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if (cpus_conf > 0 && cpus_onln < 0) {
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cpus = cpus_conf;
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} else if (cpus_onln > 0 && cpus_conf < 0) {
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cpus = cpus_onln;
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} else if (cpus_onln > 0 && cpus_conf > 0) {
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if (cpus_onln < cpus_conf) {
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log_notice(LD_GENERAL, "I think we have %ld CPUS, but only %ld of them "
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"are available. Telling Tor to only use %ld. You can over"
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"ride this with the NumCPUs option",
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cpus_conf, cpus_onln, cpus_onln);
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}
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cpus = cpus_onln;
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}
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if (cpus >= 1 && cpus < INT_MAX)
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return (int)cpus;
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else
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return -1;
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#else
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return -1;
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#endif /* defined(_WIN32) || ... */
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}
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#define MAX_DETECTABLE_CPUS 16
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/** Return how many CPUs we are running with. We assume that nobody is
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* using hot-swappable CPUs, so we don't recompute this after the first
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* time. Return -1 if we don't know how to tell the number of CPUs on this
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* system.
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*/
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int
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compute_num_cpus(void)
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{
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static int num_cpus = -2;
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if (num_cpus == -2) {
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num_cpus = compute_num_cpus_impl();
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tor_assert(num_cpus != -2);
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if (num_cpus > MAX_DETECTABLE_CPUS) {
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/* LCOV_EXCL_START */
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log_notice(LD_GENERAL, "Wow! I detected that you have %d CPUs. I "
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"will not autodetect any more than %d, though. If you "
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"want to configure more, set NumCPUs in your torrc",
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num_cpus, MAX_DETECTABLE_CPUS);
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num_cpus = MAX_DETECTABLE_CPUS;
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/* LCOV_EXCL_STOP */
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}
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}
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return num_cpus;
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}
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