Mercurial > MadButterfly
view src/timertool.c @ 795:46a4cd4d382b
Remove dependent on system time to gain frame rate
Date.now() would read system time. It is ineffeciency in for some
implementation. To gain frame rate, we should rely on accuration of
setInterval().
author | Thinker K.F. Li <thinker@codemud.net> |
---|---|
date | Tue, 31 Aug 2010 10:04:15 +0800 |
parents | 530bb7728546 |
children | 586e50f82c1f |
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#include <stdio.h> #include <sys/time.h> #ifdef __FreeBSD__ #include <machine/cpufunc.h> #include <sys/types.h> #include <sys/sysctl.h> #endif #include "mb_timer.h" #ifdef __FreeBSD__ void get_now(mb_timeval_t *tmo) { struct timeval tv; static uint64_t cpufreq; static uint64_t diff; static mb_timeval_t tm = {0, 0}; static uint64_t last_ts; mb_timeval_t diff_tm; uint64_t ts, udiff, sdiff; size_t sysctl_sz; int r; if(MB_TIMEVAL_SEC(&tm) == 0) { sysctl_sz = sizeof(uint64_t); r = sysctlbyname("kern.timecounter.tc.TSC.frequency", &cpufreq, &sysctl_sz, NULL, 0); if(r == -1) { perror("sysctl"); return; } gettimeofday(&tv, NULL); last_ts = rdtsc(); MB_TIMEVAL_SET(tmo, tv.tv_sec, tv.tv_usec); MB_TIMEVAL_CP(&tm, tmo); diff = 0; } else { ts = rdtsc(); diff += ts - last_ts; sdiff = diff / cpufreq; udiff = (diff % cpufreq) * 1000000 / cpufreq; MB_TIMEVAL_SET(&diff_tm, sdiff, udiff); MB_TIMEVAL_CP(tmo, &tm); MB_TIMEVAL_ADD(tmo, &diff_tm); MB_TIMEVAL_SET(&diff_tm, sdiff, 0); MB_TIMEVAL_ADD(&tm, &diff_tm); diff %= cpufreq; last_ts = ts; } } #else /* __FreeBSD__ */ void get_now(mb_timeval_t *tmo) { struct timeval tv; gettimeofday(&tv, NULL); MB_TIMEVAL_SET(tmo, tv.tv_sec, tv.tv_usec); } #endif /* __FreeBSD__ */