Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760943AbZJIOYu (ORCPT ); Fri, 9 Oct 2009 10:24:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760933AbZJIOYt (ORCPT ); Fri, 9 Oct 2009 10:24:49 -0400 Received: from hera.kernel.org ([140.211.167.34]:42843 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760906AbZJIOYs (ORCPT ); Fri, 9 Oct 2009 10:24:48 -0400 Date: Fri, 9 Oct 2009 14:23:35 GMT From: tip-bot for Ingo Molnar Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, torvalds@linux-foundation.org, arjan@linux.intel.com, efault@gmx.de, elendil@planet.nl, peterz@infradead.org, tglx@linutronix.de, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, arjan@linux.intel.com, torvalds@linux-foundation.org, peterz@infradead.org, elendil@planet.nl, efault@gmx.de, tglx@linutronix.de, mingo@elte.hu In-Reply-To: <20091008064041.67219b13@infradead.org> References: <20091008064041.67219b13@infradead.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/urgent] Revert "x86, timers: Check for pending timers after (device) interrupts" Message-ID: Git-Commit-ID: e7ab0f7b50bc4688fb5cf65de5d42e3b882fb8d1 X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Fri, 09 Oct 2009 14:23:36 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2520 Lines: 73 Commit-ID: e7ab0f7b50bc4688fb5cf65de5d42e3b882fb8d1 Gitweb: http://git.kernel.org/tip/e7ab0f7b50bc4688fb5cf65de5d42e3b882fb8d1 Author: Ingo Molnar AuthorDate: Fri, 9 Oct 2009 15:58:20 +0200 Committer: Ingo Molnar CommitDate: Fri, 9 Oct 2009 15:58:20 +0200 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, 0 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c index 3912061..74656d1 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 d915d95..ec1de97 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 */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/