From aa42fc0e9cd965a52fbcdc289bad94645ae59afe Mon Sep 17 00:00:00 2001 From: Keir Fraser Date: Thu, 17 Jun 2010 08:52:29 +0100 Subject: [PATCH] cpuidle: remove hpet access in hpet_broadcast_exit hpet_broadcast_exit calls reprogram_hpet to stop possible hpet intr if the last deep-cstate waken up cpu is waken by unexpected intrs instead of hpet broadcast handler. This can be removed without brings much useless intrs, but bring chance for further optimization. It is a tradeoff between grace & optimization. BTW, move the cpumask set out of critial section in hpet_broadcast_enter to shorten it. Signed-off-by: Wei Gang --- xen/arch/x86/hpet.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) diff --git a/xen/arch/x86/hpet.c b/xen/arch/x86/hpet.c index 47cc82ea21..4bfc11d9c4 100644 --- a/xen/arch/x86/hpet.c +++ b/xen/arch/x86/hpet.c @@ -664,14 +664,12 @@ void hpet_broadcast_enter(void) /* Disable LAPIC timer interrupts. */ disable_APIC_timer(); + cpu_set(cpu, ch->cpumask); spin_lock(&ch->lock); - - cpu_set(cpu, ch->cpumask); /* reprogram if current cpu expire time is nearer */ if ( this_cpu(timer_deadline_end) < ch->next_event ) reprogram_hpet_evt_channel(ch, this_cpu(timer_deadline_end), NOW(), 1); - spin_unlock(&ch->lock); } @@ -692,11 +690,7 @@ void hpet_broadcast_exit(void) raise_softirq(TIMER_SOFTIRQ); spin_lock_irq(&ch->lock); - cpu_clear(cpu, ch->cpumask); - if ( cpus_empty(ch->cpumask) && ch->next_event != STIME_MAX ) - reprogram_hpet_evt_channel(ch, STIME_MAX, 0, 0); - spin_unlock_irq(&ch->lock); if ( ch != &legacy_hpet_event ) -- 2.30.2