From 44adb31bfece29260a9bbd9075c9212ebf00d24d Mon Sep 17 00:00:00 2001 From: Daniel Stone Date: Fri, 27 Aug 2010 20:36:37 +1000 Subject: [PATCH] GetTimeInMillis: Use CLOCK_MONOTONIC_COARSE where available On some systems, using CLOCK_MONOTONIC forces a readback of HPET or some similarly expensive timer. CLOCK_MONOTONIC_COARSE can alleviate this, at the cost of negligibly-reduced resolution, so prefer that where we can. Signed-off-by: Daniel Stone Reviewed-by: Julien Cristau Reviewed-by: Tiago Vignatti --- os/utils.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/os/utils.c b/os/utils.c index afdff0c5a..18fd91151 100644 --- a/os/utils.c +++ b/os/utils.c @@ -427,7 +427,21 @@ GetTimeInMillis(void) #ifdef MONOTONIC_CLOCK struct timespec tp; - if (clock_gettime(CLOCK_MONOTONIC, &tp) == 0) + static clockid_t clockid; + if (!clockid) { +#ifdef CLOCK_MONOTONIC_COARSE + if (clock_getres(CLOCK_MONOTONIC_COARSE, &tp) == 0 && + (tp.tv_nsec / 1000) <= 1000 && + clock_gettime(CLOCK_MONOTONIC_COARSE, &tp) == 0) + clockid = CLOCK_MONOTONIC_COARSE; + else +#endif + if (clock_gettime(CLOCK_MONOTONIC, &tp) == 0) + clockid = CLOCK_MONOTONIC; + else + clockid = ~0L; + } + if (clockid != ~0L && clock_gettime(clockid, &tp) == 0) return (tp.tv_sec * 1000) + (tp.tv_nsec / 1000000L); #endif