x86/tsc: Add option to disable tsc clocksource watchdog

Clocksource watchdog has been found responsible for generating latency
spikes (in the 10-20 us range) when woken up to check for TSC stability.

Add an option to disable it at boot.

Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: bigeasy@linutronix.de
Cc: linux-rt-users@vger.kernel.org
Cc: peterz@infradead.org
Cc: bristot@redhat.com
Cc: williams@redhat.com
Link: https://lkml.kernel.org/r/20190307120913.13168-1-juri.lelli@redhat.com
This commit is contained in:
Juri Lelli
2019-03-07 13:09:13 +01:00
committed by Thomas Gleixner
parent 9e98c678c2
commit 0f0b7e1cc7
2 changed files with 8 additions and 1 deletions

View File

@@ -4703,6 +4703,10 @@
[x86] unstable: mark the TSC clocksource as unstable, this
marks the TSC unconditionally unstable at bootup and
avoids any further wobbles once the TSC watchdog notices.
[x86] nowatchdog: disable clocksource watchdog. Used
in situations with strict latency requirements (where
interruptions from clocksource watchdog are not
acceptable).
turbografx.map[2|3]= [HW,JOY]
TurboGraFX parallel port interface