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| author | Sergei Trofimovich <slyich@gmail.com> | 2022-08-20 19:18:13 +0100 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2022-09-11 21:55:07 -0700 |
| commit | aa06a9bd853306c239f759018fb227d7e8f4e203 (patch) | |
| tree | 1fe5f4e788106cf7a1b71adbd210d6cb9159ac12 /fs/eventpoll.c | |
| parent | cba7543e1515e79a85d37df85a0eb2cf0f07d115 (diff) | |
| download | linux-aa06a9bd853306c239f759018fb227d7e8f4e203.tar.gz linux-aa06a9bd853306c239f759018fb227d7e8f4e203.tar.bz2 linux-aa06a9bd853306c239f759018fb227d7e8f4e203.zip | |
ia64: fix clock_getres(CLOCK_MONOTONIC) to report ITC frequency
clock_gettime(CLOCK_MONOTONIC, &tp) is very precise on ia64 as it uses ITC
(similar to rdtsc on x86). It's not quite a hrtimer as it is a few times
slower than 1ns. Usually 2-3ns.
clock_getres(CLOCK_MONOTONIC, &res) never reflected that fact and reported
0.04s precision (1/HZ value).
In https://bugs.gentoo.org/596382 gstreamer's test suite failed loudly
when it noticed precision discrepancy.
Before the change:
clock_getres(CLOCK_MONOTONIC, &res) reported 250Hz precision.
After the change:
clock_getres(CLOCK_MONOTONIC, &res) reports ITC (400Mhz) precision.
The patch is based on matoro's fix. I added a bit of explanation why we
need to special-case arch-specific clock_getres().
[akpm@linux-foundation.org: coding-style cleanups]
Link: https://lkml.kernel.org/r/20220820181813.2275195-1-slyich@gmail.com
Signed-off-by: Sergei Trofimovich <slyich@gmail.com>
Cc: matoro <matoro_mailinglist_kernel@matoro.tk>
Cc: Émeric Maschino <emeric.maschino@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'fs/eventpoll.c')
0 files changed, 0 insertions, 0 deletions