From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752269AbeDBPRk (ORCPT ); Mon, 2 Apr 2018 11:17:40 -0400 Received: from mail.kernel.org ([198.145.29.99]:32922 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751255AbeDBPRj (ORCPT ); Mon, 2 Apr 2018 11:17:39 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AA82B20838 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=rostedt@goodmis.org Date: Mon, 2 Apr 2018 11:17:36 -0400 From: Steven Rostedt To: Chris Wilson Cc: linux-kernel@vger.kernel.org, intel-gfx@lists.freedesktop.org Subject: Re: [PATCH v2 1/2] trace: Default to using trace_global_clock if sched_clock is unstable Message-ID: <20180402111736.763c861e@gandalf.local.home> In-Reply-To: <20180330150132.16903-1-chris@chris-wilson.co.uk> References: <20180330150132.16903-1-chris@chris-wilson.co.uk> X-Mailer: Claws Mail 3.16.0 (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 30 Mar 2018 16:01:31 +0100 Chris Wilson wrote: > Across suspend, we may see a very large drift in timestamps if the sched > clock is unstable, prompting the global trace's ringbuffer code to warn > and suggest switching to the global clock. Preempt this request by > detecting when the sched clock is unstable (determined during > late_initcall) and automatically switching the default clock over to > trace_global_clock. > > This should prevent requiring user interaction to resolve warnings such > as: > > Delta way too big! 18446743856563626466 ts=18446744054496180323 write stamp = 197932553857 > If you just came from a suspend/resume, > please switch to the trace global clock: > echo global > /sys/kernel/debug/tracing/trace_clock > > Signed-off-by: Chris Wilson > Cc: Steven Rostedt (VMware) > --- > v2: Tell the user what's happening and what they can do to correct it. > Thanks, I pulled them in. I'll start testing them before I post to git. -- Steve