diff options
| author | Paul E. McKenney <paulmck@kernel.org> | 2023-02-01 13:53:07 -0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2023-02-06 16:38:30 -0800 |
| commit | 0051293c533017e2a860e0a0a33517bc40240fff (patch) | |
| tree | 54297a31350169661fd6f40446cf5f49025dd9bd /Documentation/admin-guide | |
| parent | efc8b329c7fdc30921a7dfc109237523e1e5b1cc (diff) | |
clocksource: Enable TSC watchdog checking of HPET and PMTMR only when requested
Unconditionally enabling TSC watchdog checking of the HPET and PMTMR
clocksources can degrade latency and performance. Therefore, provide
a new "watchdog" option to the tsc= boot parameter that opts into such
checking. Note that tsc=watchdog is overridden by a tsc=nowatchdog
regardless of their relative positions in the list of boot parameters.
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Waiman Long <longman@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Acked-by: Waiman Long <longman@redhat.com>
Diffstat (limited to 'Documentation/admin-guide')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 95f0d104c232..7b4df6d89d3c 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -6373,6 +6373,12 @@ (HPET or PM timer) on systems whose TSC frequency was obtained from HW or FW using either an MSR or CPUID(0x15). Warn if the difference is more than 500 ppm. + [x86] watchdog: Use TSC as the watchdog clocksource with + which to check other HW timers (HPET or PM timer), but + only on systems where TSC has been deemed trustworthy. + This will be suppressed by an earlier tsc=nowatchdog and + can be overridden by a later tsc=nowatchdog. A console + message will flag any such suppression or overriding. tsc_early_khz= [X86] Skip early TSC calibration and use the given value instead. Useful when the early TSC frequency discovery |