diff options
| author | Petri Savolainen <petri.savolainen@linaro.org> | 2017-04-28 15:09:57 +0300 |
|---|---|---|
| committer | Maxim Uvarov <maxim.uvarov@linaro.org> | 2017-06-16 16:51:11 +0300 |
| commit | 60150bba495711e6fdfc948ffb4ad405878fbcbc (patch) | |
| tree | f56eeb31e1e26857fb2fddfad7e1563efa74919d /platform/linux-generic | |
| parent | fbe34c754b7abe15100779ce9833a7f200517d9f (diff) | |
linux-gen: time: improve x86 TSC freq measurement accuracy
Add short warm up round and measure over a longer period of
time (250ms vs 100ms).
Signed-off-by: Petri Savolainen <petri.savolainen@linaro.org>
Reviewed-and-tested-by: Bill Fischofer <bill.fischofer@linaro.org>
Signed-off-by: Maxim Uvarov <maxim.uvarov@linaro.org>
Diffstat (limited to 'platform/linux-generic')
| -rw-r--r-- | platform/linux-generic/arch/x86/odp_cpu_arch.c | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/platform/linux-generic/arch/x86/odp_cpu_arch.c b/platform/linux-generic/arch/x86/odp_cpu_arch.c index 9ba601a32..b1da428b9 100644 --- a/platform/linux-generic/arch/x86/odp_cpu_arch.c +++ b/platform/linux-generic/arch/x86/odp_cpu_arch.c @@ -54,11 +54,16 @@ uint64_t cpu_global_time_freq(void) uint64_t t1, t2, ts_nsec, cycles, hz; int i; uint64_t avg = 0; - int rounds = 4; + int rounds = 3; + int warm_up = 1; for (i = 0; i < rounds; i++) { - sleep.tv_sec = 0; - sleep.tv_nsec = SEC_IN_NS / 10; + sleep.tv_sec = 0; + + if (warm_up) + sleep.tv_nsec = SEC_IN_NS / 1000; + else + sleep.tv_nsec = SEC_IN_NS / 4; if (clock_gettime(CLOCK_MONOTONIC_RAW, &ts1)) { ODP_DBG("clock_gettime failed\n"); @@ -85,8 +90,12 @@ uint64_t cpu_global_time_freq(void) cycles = t2 - t1; hz = (cycles * SEC_IN_NS) / ts_nsec; - avg += hz; + + if (warm_up) + warm_up = 0; + else + avg += hz; } - return avg / rounds; + return avg / (rounds - 1); } |