diff options
| author | Song Liu <song@kernel.org> | 2024-04-29 23:02:36 -0700 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-05-08 08:41:29 -0700 |
| commit | 393fb313a2e150b768e4850658679e2afff431e9 (patch) | |
| tree | 78dca4066c9e72b70b2eb4ce5dd6faccf3b42c93 /include/linux/nmi.h | |
| parent | 602ba77361160d99c77e3dadf7d891364f8c71b3 (diff) | |
watchdog: allow nmi watchdog to use raw perf event
NMI watchdog permanently consumes one hardware counters per CPU on the
system. For systems that use many hardware counters, this causes more
aggressive time multiplexing of perf events.
OTOH, some CPUs (mostly Intel) support "ref-cycles" event, which is rarely
used. Add kernel cmdline arg nmi_watchdog=rNNN to configure the watchdog
to use raw event. For example, on Intel CPUs, we can use "r300" to
configure the watchdog to use ref-cycles event.
If the raw event does not work, fall back to use "cycles".
[akpm@linux-foundation.org: fix kerneldoc]
Link: https://lkml.kernel.org/r/20240430060236.1878002-2-song@kernel.org
Signed-off-by: Song Liu <song@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include/linux/nmi.h')
| -rw-r--r-- | include/linux/nmi.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/nmi.h b/include/linux/nmi.h index f53438eae815..a8dfb38c9bb6 100644 --- a/include/linux/nmi.h +++ b/include/linux/nmi.h @@ -105,10 +105,12 @@ void watchdog_hardlockup_check(unsigned int cpu, struct pt_regs *regs); extern void hardlockup_detector_perf_stop(void); extern void hardlockup_detector_perf_restart(void); extern void hardlockup_detector_perf_cleanup(void); +extern void hardlockup_config_perf_event(const char *str); #else static inline void hardlockup_detector_perf_stop(void) { } static inline void hardlockup_detector_perf_restart(void) { } static inline void hardlockup_detector_perf_cleanup(void) { } +static inline void hardlockup_config_perf_event(const char *str) { } #endif void watchdog_hardlockup_stop(void); |