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xz-archive/src/xz/hardware.c
Lasse Collin 1880a3927b Renamed lzma to xz and lzmadec to xzdec. We create symlinks
lzma, unlzma, and lzcat in "make install" for backwards
compatibility with LZMA Utils 4.32.x; I'm not sure if this
should be the default though.
2008-11-19 23:52:24 +02:00

122 lines
3.1 KiB
C

///////////////////////////////////////////////////////////////////////////////
//
/// \file hardware.c
/// \brief Detection of available hardware resources
//
// Copyright (C) 2007 Lasse Collin
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
///////////////////////////////////////////////////////////////////////////////
#include "private.h"
#include "physmem.h"
/// Maximum number of free *coder* threads. This can be set with
/// the --threads=NUM command line option.
size_t opt_threads = 1;
/// Memory usage limit for encoding
static uint64_t memlimit_encoder;
/// Memory usage limit for decoding
static uint64_t memlimit_decoder;
/// Memory usage limit given on the command line or environment variable.
/// Zero indicates the default (memlimit_encoder or memlimit_decoder).
static uint64_t memlimit_custom = 0;
/// Get the number of CPU cores, and set opt_threads to default to that value.
/// User can then override this with --threads command line option.
static void
hardware_cores(void)
{
#if defined(HAVE_NUM_PROCESSORS_SYSCONF)
const long cpus = sysconf(_SC_NPROCESSORS_ONLN);
if (cpus > 0)
opt_threads = (size_t)(cpus);
#elif defined(HAVE_NUM_PROCESSORS_SYSCTL)
int name[2] = { CTL_HW, HW_NCPU };
int cpus;
size_t cpus_size = sizeof(cpus);
if (!sysctl(name, &cpus, &cpus_size, NULL, NULL)
&& cpus_size == sizeof(cpus) && cpus > 0)
opt_threads = (size_t)(cpus);
#endif
// Limit opt_threads so that maximum number of threads doesn't exceed.
#if defined(_SC_THREAD_THREADS_MAX)
const long threads_max = sysconf(_SC_THREAD_THREADS_MAX);
if (threads_max > 0 && (size_t)(threads_max) < opt_threads)
opt_threads = (size_t)(threads_max);
#elif defined(PTHREAD_THREADS_MAX)
if (opt_threads > PTHREAD_THREADS_MAX)
opt_threads = PTHREAD_THREADS_MAX;
#endif
return;
}
static void
hardware_memlimit_init(void)
{
uint64_t mem = physmem();
// If we cannot determine the amount of RAM, assume 32 MiB. Maybe
// even that is too much on some systems. But on most systems it's
// far too little, and can be annoying.
if (mem == 0)
mem = UINT64_C(16) * 1024 * 1024;
// Use at maximum of 90 % of RAM when encoding and 33 % when decoding.
memlimit_encoder = mem - mem / 10;
memlimit_decoder = mem / 3;
return;
}
extern void
hardware_memlimit_set(uint64_t memlimit)
{
memlimit_custom = memlimit;
return;
}
extern uint64_t
hardware_memlimit_encoder(void)
{
return memlimit_custom != 0 ? memlimit_custom : memlimit_encoder;
}
extern uint64_t
hardware_memlimit_decoder(void)
{
return memlimit_custom != 0 ? memlimit_custom : memlimit_decoder;
}
extern void
hardware_init(void)
{
hardware_memlimit_init();
hardware_cores();
return;
}