Tickless is disabled by nohz=off, which is used in OSVs. But in current kernel, if tickless is disabled, the timer irq0 will not increase. Because the timer event handler should be tick_handle_periodic, but actually event handler keep as tick_handle_oneshot_broadcast which is used in tickless. The root cause is that it is default to enable high resolution timer which will force to oneshot broadcast mode. This patch add tickless enable check before enable high resolution timer On Nehalem-EX: Before the patch: linux-a25n:~ # cat /proc/interrupts | grep timer 0: 334 0 0 0 0 0 .... LOC: 192248 193931 193851 184441 193803 193625 .... After the patch: cat /proc/interrupts | grep timer 0: 223788 0 0 0 0 0 .... LOC: 13081 238407 238452 229405 238298 235688 .... Signed-off-by: Youquan, Song <youquan.song@xxxxxxxxx> --- diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index f992762..a515bed 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -815,7 +815,7 @@ int tick_check_oneshot_change(int allow_nohz) if (!timekeeping_valid_for_hres() || !tick_is_oneshot_available()) return 0; - if (!allow_nohz) + if (!allow_nohz && tick_nohz_enabled) return 1; tick_nohz_switch_to_nohz(); -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
