Re: [RESEND PATCH] x86/vdso: Handle clock_gettime(CLOCK_TAI) in vDSO

From: Thomas Gleixner
Date: Fri Aug 31 2018 - 14:45:43 EST


On Wed, 29 Aug 2018, Matthew Rickard wrote:

> Here are the before and after times with CONFIG_RETPOLINE=y always on.
> I don't see any regression, just the hoped-for improvement on glibc and
> vDSO calls of CLOCK_TAI.
>
> Before:
> sec Timestamp nanos clockname tzname type
> ---------- --------------------------- ----- --------- --------- -------
> 1535445844 2018/08/28 08:44:04.338599419 96 CLOCK_REALTIME UTC 0 glibc
> 1535445844 2018/08/28 08:44:04.348494684 87 CLOCK_REALTIME UTC 1 vdso
> 1535445844 2018/08/28 08:44:04.357328913 321 CLOCK_REALTIME UTC 2 sys
> 1535445834 2018/08/28 08:43:27.507099055 233 CLOCK_TAI right/UTC 0 glibc
> 1535445834 2018/08/28 08:43:27.530666383 239 CLOCK_TAI right/UTC 1 vdso
> 1535445834 2018/08/28 08:43:27.554827262 389 CLOCK_TAI right/UTC 2 sys
> 80 1970/01/01 00:01:20.593942210 88 CLOCK_MONOTONIC UTC 0 glibc
> 80 1970/01/01 00:01:20.602866312 84 CLOCK_MONOTONIC UTC 1 vdso
> 80 1970/01/01 00:01:20.611322392 272 CLOCK_MONOTONIC UTC 2 sys
> 80 1970/01/01 00:01:20.638630685 298 CLOCK_BOOTTIME UTC 0 glibc
> 80 1970/01/01 00:01:20.668487920 293 CLOCK_BOOTTIME UTC 1 vdso
> 80 1970/01/01 00:01:20.697818847 279 CLOCK_BOOTTIME UTC 2 sys
>
> After yours and my patches:
> sec Timestamp nanos clockname tzname type
> ---------- --------------------------- ----- --------- --------- -------
> 1535466985 2018/08/28 14:36:25.483377529 93 CLOCK_REALTIME UTC 0 glibc
> 1535466985 2018/08/28 14:36:25.493020681 89 CLOCK_REALTIME UTC 1 vdso
> 1535466985 2018/08/28 14:36:25.502139080 282 CLOCK_REALTIME UTC 2 sys
> 1535466975 2018/08/28 14:35:48.530621935 87 CLOCK_TAI right/UTC 0 glibc
> 1535466975 2018/08/28 14:35:48.539393751 81 CLOCK_TAI right/UTC 1 vdso
> 1535466975 2018/08/28 14:35:48.547693183 276 CLOCK_TAI right/UTC 2 sys
> 224 1970/01/01 00:03:44.575542852 87 CLOCK_MONOTONIC UTC 0 glibc
> 224 1970/01/01 00:03:44.584329822 81 CLOCK_MONOTONIC UTC 1 vdso
> 224 1970/01/01 00:03:44.592473982 269 CLOCK_MONOTONIC UTC 2 sys
> 224 1970/01/01 00:03:44.619450784 296 CLOCK_BOOTTIME UTC 0 glibc
> 224 1970/01/01 00:03:44.649224430 312 CLOCK_BOOTTIME UTC 1 vdso
> 224 1970/01/01 00:03:44.680600544 297 CLOCK_BOOTTIME UTC 2 sys

Can you please send a V3 with that information (condensed) in the
changelog?

Thanks,

tglx