diff options
Diffstat (limited to 'include/linux/clocksource.h')
| -rw-r--r-- | include/linux/clocksource.h | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h index 1d42d4b17327..0ad8b550bb4b 100644 --- a/include/linux/clocksource.h +++ b/include/linux/clocksource.h @@ -291,7 +291,19 @@ static inline void timer_probe(void) {} #define TIMER_ACPI_DECLARE(name, table_id, fn) \ ACPI_DECLARE_PROBE_ENTRY(timer, name, table_id, 0, NULL, 0, fn) -extern ulong max_cswd_read_retries; +static inline unsigned int clocksource_get_max_watchdog_retry(void) +{ + /* + * When system is in the boot phase or under heavy workload, there + * can be random big latencies during the clocksource/watchdog + * read, so allow retries to filter the noise latency. As the + * latency's frequency and maximum value goes up with the number of + * CPUs, scale the number of retries with the number of online + * CPUs. + */ + return (ilog2(num_online_cpus()) / 2) + 1; +} + void clocksource_verify_percpu(struct clocksource *cs); #endif /* _LINUX_CLOCKSOURCE_H */ |