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author | Lasse Collin <lasse.collin@tukaani.org> | 2007-12-09 00:42:33 +0200 |
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committer | Lasse Collin <lasse.collin@tukaani.org> | 2007-12-09 00:42:33 +0200 |
commit | 5d018dc03549c1ee4958364712fb0c94e1bf2741 (patch) | |
tree | 1b211911fb33fddb3f04b77f99e81df23623ffc4 /src/lzma/hardware.c | |
download | xz-5d018dc03549c1ee4958364712fb0c94e1bf2741.tar.xz |
Imported to git.
Diffstat (limited to '')
-rw-r--r-- | src/lzma/hardware.c | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/src/lzma/hardware.c b/src/lzma/hardware.c new file mode 100644 index 00000000..6cb3cdfc --- /dev/null +++ b/src/lzma/hardware.c @@ -0,0 +1,99 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \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; + + +/// Number of bytes of memory to use at maximum (only a rough limit). +/// This can be set with the --memory=NUM command line option. +/// If no better value can be determined, the default is 14 MiB, which +/// should be quite safe even for older systems while still allowing +/// reasonable compression ratio. +size_t opt_memory = 14 * 1024 * 1024; + + +/// Get the amount of physical memory, and set opt_memory to 1/3 of it. +/// User can then override this with --memory command line option. +static void +hardware_memory(void) +{ + uint64_t mem = physmem(); + if (mem != 0) { + mem /= 3; + +#if UINT64_MAX > SIZE_MAX + if (mem > SIZE_MAX) + mem = SIZE_MAX; +#endif + + opt_memory = mem; + } + + return; +} + + +/// 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; +} + + +extern void +hardware_init(void) +{ + hardware_memory(); + hardware_cores(); + return; +} |