From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932411Ab0C3XxJ (ORCPT ); Tue, 30 Mar 2010 19:53:09 -0400 Received: from kroah.org ([198.145.64.141]:45756 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932417Ab0C3XT3 (ORCPT ); Tue, 30 Mar 2010 19:19:29 -0400 X-Mailbox-Line: From linux@linux.site Tue Mar 30 15:47:32 2010 Message-Id: <20100330224732.429575021@linux.site> User-Agent: quilt/0.47-14.9 Date: Tue, 30 Mar 2010 15:40:53 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Frederic Weisbecker , Peter Zijlstra , "K.Prasad" , Paul Mackerras , Greg Kroah-Hartman Subject: [019/156] hw-breakpoints: Remove stub unthrottle callback In-Reply-To: <20100330230630.GA28824@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.33-stable review patch. If anyone has any objections, please let us know. ------------------ From: Frederic Weisbecker commit 1e259e0a9982078896f3404240096cbea01daca4 upstream. We support event unthrottling in breakpoint events. It means that if we have more than sysctl_perf_event_sample_rate/HZ, perf will throttle, ignoring subsequent events until the next tick. So if ptrace exceeds this max rate, it will omit events, which breaks the ptrace determinism that is supposed to report every triggered breakpoints. This is likely to happen if we set sysctl_perf_event_sample_rate to 1. This patch removes support for unthrottling in breakpoint events to break throttling and restore ptrace determinism. Signed-off-by: Frederic Weisbecker Cc: Peter Zijlstra Cc: K.Prasad Cc: Paul Mackerras Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/hw_breakpoint.c | 5 ----- kernel/hw_breakpoint.c | 1 - 2 files changed, 6 deletions(-) --- a/arch/x86/kernel/hw_breakpoint.c +++ b/arch/x86/kernel/hw_breakpoint.c @@ -531,8 +531,3 @@ void hw_breakpoint_pmu_read(struct perf_ { /* TODO */ } - -void hw_breakpoint_pmu_unthrottle(struct perf_event *bp) -{ - /* TODO */ -} --- a/kernel/hw_breakpoint.c +++ b/kernel/hw_breakpoint.c @@ -489,5 +489,4 @@ struct pmu perf_ops_bp = { .enable = arch_install_hw_breakpoint, .disable = arch_uninstall_hw_breakpoint, .read = hw_breakpoint_pmu_read, - .unthrottle = hw_breakpoint_pmu_unthrottle };