From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752387Ab1HJNHT (ORCPT ); Wed, 10 Aug 2011 09:07:19 -0400 Received: from mx1.redhat.com ([209.132.183.28]:35546 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751325Ab1HJNHR (ORCPT ); Wed, 10 Aug 2011 09:07:17 -0400 Date: Wed, 10 Aug 2011 09:06:52 -0400 From: Don Zickus To: Alex Neronskiy Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, Ingo Molnar , Mandeep Singh Baines , Alex Neronskiy Subject: Re: [PATCH v5 2/2] Output stall data in debugfs Message-ID: <20110810130652.GI1972@redhat.com> References: <1312935763-23570-1-git-send-email-zakmagnus@chromium.org> <1312935763-23570-2-git-send-email-zakmagnus@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1312935763-23570-2-git-send-email-zakmagnus@chromium.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 09, 2011 at 05:22:43PM -0700, Alex Neronskiy wrote: > From: Alex Neronskiy > > Instead of using the log, use debugfs for output of both stall > lengths and stack traces. Printing to the log can result in > watchdog touches, distorting the very events being measured. > Additionally, the information will not distract from lockups > when users view the log. > > A two-buffer system is used to ensure that the trace information > can always be recorded without contention. This looks like it can work. I'll try to play with it today. Can I ask that you add some comments to document the way the buffers work, so others know what is going on to. Cheers, Don