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| author | Andreas Ericsson <ae@op5.se> | 2008-02-23 02:11:56 (GMT) |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2008-02-23 20:00:32 (GMT) |
| commit | 833e3df17188e48b2d31db0966a4051dad5e03b9 (patch) | |
| tree | 265fb9405efb644ff564ac1b77991d62795006a2 /thread-utils.c | |
| parent | 923d44aeb7cb6d21eeb459fdc1b58137e37c2b1c (diff) | |
| download | git-833e3df17188e48b2d31db0966a4051dad5e03b9.zip git-833e3df17188e48b2d31db0966a4051dad5e03b9.tar.gz git-833e3df17188e48b2d31db0966a4051dad5e03b9.tar.bz2 | |
pack-objects: Add runtime detection of online CPU's
Packing objects can be done in parallell nowadays, but it's
only done if the config option pack.threads is set to a value
above 1. Because of that, the code-path used is often not the
most optimal one.
This patch adds a routine to detect the number of online CPU's
at runtime (online_cpus()). When pack.threads (or --threads=) is
given a value of 0, the number of threads is set to the number of
online CPU's. This feature is also documented.
As per Nicolas Pitre's recommendations, the default is still to
run pack-objects single-threaded unless explicitly activated,
either by configuration or by command line parameter.
The routine online_cpus() is a rework of "numcpus.c", written by
one Philip Willoughby <pgw99@doc.ic.ac.uk>. numcpus.c is in the
public domain and can presently be downloaded from
http://csgsoft.doc.ic.ac.uk/numcpus/
Signed-off-by: Andreas Ericsson <ae@op5.se>
Signed-off-by: Brandon Casey <casey@nrlssc.navy.mil>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'thread-utils.c')
| -rw-r--r-- | thread-utils.c | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/thread-utils.c b/thread-utils.c new file mode 100644 index 0000000..55e7e29 --- /dev/null +++ b/thread-utils.c @@ -0,0 +1,48 @@ +#include "cache.h" + +#ifdef _WIN32 +# define WIN32_LEAN_AND_MEAN +# include <windows.h> +#elif defined(hpux) || defined(__hpux) || defined(_hpux) +# include <sys/pstat.h> +#endif + +/* + * By doing this in two steps we can at least get + * the function to be somewhat coherent, even + * with this disgusting nest of #ifdefs. + */ +#ifndef _SC_NPROCESSORS_ONLN +# ifdef _SC_NPROC_ONLN +# define _SC_NPROCESSORS_ONLN _SC_NPROC_ONLN +# elif defined _SC_CRAY_NCPU +# define _SC_NPROCESSORS_ONLN _SC_CRAY_NCPU +# endif +#endif + +int online_cpus(void) +{ +#ifdef _SC_NPROCESSORS_ONLN + long ncpus; +#endif + +#ifdef _WIN32 + SYSTEM_INFO info; + GetSystemInfo(&info); + + if ((int)info.dwNumberOfProcessors > 0) + return (int)info.dwNumberOfProcessors; +#elif defined(hpux) || defined(__hpux) || defined(_hpux) + struct pst_dynamic psd; + + if (!pstat_getdynamic(&psd, sizeof(psd), (size_t)1, 0)) + return (int)psd.psd_proc_cnt; +#endif + +#ifdef _SC_NPROCESSORS_ONLN + if ((ncpus = (long)sysconf(_SC_NPROCESSORS_ONLN)) > 0) + return (int)ncpus; +#endif + + return 1; +} |