0ec79358d0
When built with NO_PTHREADS, the macros are used make the code build even though pthreads header and library may be missing. The code can still have different code paths for no threads support with HAVE_THREADS variable. There are of course impacts on no-pthreads builds: - data structure may get slightly bigger because all the mutexes and pthread_t are present (as an int) - code execution is not impacted much. Locking (in hot path) is no-op. Other wrapper function calls really should not matter much. - the binary size grows bigger because of threaded code. But at least on Linux this does not matter, if some code is not executed, it's not mapped in memory. This is a preparation step to remove "#ifdef NO_PTHREADS" in the code mostly because of maintainability. As Jeff put it > it's probably OK to stop thinking of it as "non-threaded platforms > are the default and must pay zero cost" and more as "threaded > platforms are the default, and non-threaded ones are OK to pay a > small cost as long as they still work". Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
126 lines
2.6 KiB
C
126 lines
2.6 KiB
C
#include "cache.h"
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#include "thread-utils.h"
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#if defined(hpux) || defined(__hpux) || defined(_hpux)
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# include <sys/pstat.h>
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#endif
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/*
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* By doing this in two steps we can at least get
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* the function to be somewhat coherent, even
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* with this disgusting nest of #ifdefs.
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*/
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#ifndef _SC_NPROCESSORS_ONLN
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# ifdef _SC_NPROC_ONLN
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# define _SC_NPROCESSORS_ONLN _SC_NPROC_ONLN
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# elif defined _SC_CRAY_NCPU
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# define _SC_NPROCESSORS_ONLN _SC_CRAY_NCPU
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# endif
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#endif
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int online_cpus(void)
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{
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#ifdef NO_PTHREADS
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return 1;
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#else
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#ifdef _SC_NPROCESSORS_ONLN
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long ncpus;
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#endif
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#ifdef GIT_WINDOWS_NATIVE
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SYSTEM_INFO info;
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GetSystemInfo(&info);
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if ((int)info.dwNumberOfProcessors > 0)
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return (int)info.dwNumberOfProcessors;
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#elif defined(hpux) || defined(__hpux) || defined(_hpux)
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struct pst_dynamic psd;
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if (!pstat_getdynamic(&psd, sizeof(psd), (size_t)1, 0))
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return (int)psd.psd_proc_cnt;
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#elif defined(HAVE_BSD_SYSCTL) && defined(HW_NCPU)
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int mib[2];
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size_t len;
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int cpucount;
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mib[0] = CTL_HW;
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# ifdef HW_AVAILCPU
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mib[1] = HW_AVAILCPU;
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len = sizeof(cpucount);
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if (!sysctl(mib, 2, &cpucount, &len, NULL, 0))
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return cpucount;
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# endif /* HW_AVAILCPU */
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mib[1] = HW_NCPU;
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len = sizeof(cpucount);
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if (!sysctl(mib, 2, &cpucount, &len, NULL, 0))
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return cpucount;
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#endif /* defined(HAVE_BSD_SYSCTL) && defined(HW_NCPU) */
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#ifdef _SC_NPROCESSORS_ONLN
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if ((ncpus = (long)sysconf(_SC_NPROCESSORS_ONLN)) > 0)
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return (int)ncpus;
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#endif
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return 1;
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#endif
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}
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int init_recursive_mutex(pthread_mutex_t *m)
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{
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#ifndef NO_PTHREADS
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pthread_mutexattr_t a;
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int ret;
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ret = pthread_mutexattr_init(&a);
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if (!ret) {
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ret = pthread_mutexattr_settype(&a, PTHREAD_MUTEX_RECURSIVE);
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if (!ret)
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ret = pthread_mutex_init(m, &a);
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pthread_mutexattr_destroy(&a);
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}
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return ret;
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#else
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return 0;
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#endif
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}
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#ifdef NO_PTHREADS
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int dummy_pthread_create(pthread_t *pthread, const void *attr,
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void *(*fn)(void *), void *data)
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{
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/*
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* Do nothing.
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*
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* The main purpose of this function is to break compiler's
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* flow analysis and avoid -Wunused-variable false warnings.
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*/
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return ENOSYS;
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}
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int dummy_pthread_init(void *data)
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{
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/*
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* Do nothing.
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*
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* The main purpose of this function is to break compiler's
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* flow analysis or it may realize that functions like
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* pthread_mutex_init() is no-op, which means the (static)
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* variable is not used/initialized at all and trigger
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* -Wunused-variable
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*/
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return ENOSYS;
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}
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int dummy_pthread_join(pthread_t pthread, void **retval)
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{
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/*
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* Do nothing.
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*
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* The main purpose of this function is to break compiler's
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* flow analysis and avoid -Wunused-variable false warnings.
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*/
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return ENOSYS;
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}
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#endif
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