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100 lines
2.7 KiB
C
100 lines
2.7 KiB
C
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///////////////////////////////////////////////////////////////////////////////
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//
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/// \file hardware.c
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/// \brief Detection of available hardware resources
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//
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// Copyright (C) 2007 Lasse Collin
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//
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// This program is free software; you can redistribute it and/or
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// modify it under the terms of the GNU Lesser General Public
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// License as published by the Free Software Foundation; either
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// version 2.1 of the License, or (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// Lesser General Public License for more details.
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//
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///////////////////////////////////////////////////////////////////////////////
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#include "private.h"
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#include "physmem.h"
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/// Maximum number of free *coder* threads. This can be set with
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/// the --threads=NUM command line option.
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size_t opt_threads = 1;
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/// Number of bytes of memory to use at maximum (only a rough limit).
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/// This can be set with the --memory=NUM command line option.
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/// If no better value can be determined, the default is 14 MiB, which
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/// should be quite safe even for older systems while still allowing
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/// reasonable compression ratio.
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size_t opt_memory = 14 * 1024 * 1024;
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/// Get the amount of physical memory, and set opt_memory to 1/3 of it.
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/// User can then override this with --memory command line option.
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static void
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hardware_memory(void)
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{
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uint64_t mem = physmem();
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if (mem != 0) {
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mem /= 3;
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#if UINT64_MAX > SIZE_MAX
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if (mem > SIZE_MAX)
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mem = SIZE_MAX;
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#endif
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opt_memory = mem;
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}
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return;
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}
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/// Get the number of CPU cores, and set opt_threads to default to that value.
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/// User can then override this with --threads command line option.
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static void
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hardware_cores(void)
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{
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#if defined(HAVE_NUM_PROCESSORS_SYSCONF)
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const long cpus = sysconf(_SC_NPROCESSORS_ONLN);
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if (cpus > 0)
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opt_threads = (size_t)(cpus);
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#elif defined(HAVE_NUM_PROCESSORS_SYSCTL)
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int name[2] = { CTL_HW, HW_NCPU };
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int cpus;
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size_t cpus_size = sizeof(cpus);
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if (!sysctl(name, &cpus, &cpus_size, NULL, NULL)
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&& cpus_size == sizeof(cpus) && cpus > 0)
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opt_threads = (size_t)(cpus);
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#endif
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// Limit opt_threads so that maximum number of threads doesn't exceed.
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#if defined(_SC_THREAD_THREADS_MAX)
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const long threads_max = sysconf(_SC_THREAD_THREADS_MAX);
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if (threads_max > 0 && (size_t)(threads_max) < opt_threads)
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opt_threads = (size_t)(threads_max);
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#elif defined(PTHREAD_THREADS_MAX)
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if (opt_threads > PTHREAD_THREADS_MAX)
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opt_threads = PTHREAD_THREADS_MAX;
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#endif
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return;
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}
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extern void
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hardware_init(void)
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{
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hardware_memory();
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hardware_cores();
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return;
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}
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