From e7ab0f7b50bc4688fb5cf65de5d42e3b882fb8d1 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Fri, 9 Oct 2009 15:58:20 +0200 Subject: [PATCH] Revert "x86, timers: Check for pending timers after (device) interrupts" This reverts commit 9bcbdd9c58617f1301dd4f17c738bb9bc73aca70. The real bug producing LatencyTop latencies has been fixed in: f5dc375: sched: Update the clock of runqueue select_task_rq() selected And the commit being reverted here triggers local timer processing from every device IRQ. If device IRQs come in at a high frequency, this could cause a performance regression. The commit being reverted here purely 'fixed' the reported latency as a side effect, because CPUs were being moved out of idle more often. Acked-by: Peter Zijlstra Cc: Arjan van de Ven Cc: Frans Pop Cc: Linus Torvalds Cc: Mike Galbraith Cc: Thomas Gleixner LKML-Reference: <20091008064041.67219b13@infradead.org> Signed-off-by: Ingo Molnar --- arch/x86/kernel/irq.c | 2 -- arch/x86/kernel/smp.c | 1 - 2 files changed, 3 deletions(-) diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c index 391206199515..74656d1d4e30 100644 --- a/arch/x86/kernel/irq.c +++ b/arch/x86/kernel/irq.c @@ -244,7 +244,6 @@ unsigned int __irq_entry do_IRQ(struct pt_regs *regs) __func__, smp_processor_id(), vector, irq); } - run_local_timers(); irq_exit(); set_irq_regs(old_regs); @@ -269,7 +268,6 @@ void smp_generic_interrupt(struct pt_regs *regs) if (generic_interrupt_extension) generic_interrupt_extension(); - run_local_timers(); irq_exit(); set_irq_regs(old_regs); diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c index d915d956e66d..ec1de97600e7 100644 --- a/arch/x86/kernel/smp.c +++ b/arch/x86/kernel/smp.c @@ -198,7 +198,6 @@ void smp_reschedule_interrupt(struct pt_regs *regs) { ack_APIC_irq(); inc_irq_stat(irq_resched_count); - run_local_timers(); /* * KVM uses this interrupt to force a cpu out of guest mode */