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 <dan...@fooishbar.org>
---
os/utils.c | 16 +++++++++++++++-
1 files changed, 15 insertions(+), 1 deletions(-)
diff --git a/os/utils.c b/os/utils.c
index afdff0c..18fd911 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
--
1.7.2.3
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