Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754609AbaK0K4K (ORCPT ); Thu, 27 Nov 2014 05:56:10 -0500 Received: from mail-wi0-f175.google.com ([209.85.212.175]:55515 "EHLO mail-wi0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754400AbaK0K4I (ORCPT ); Thu, 27 Nov 2014 05:56:08 -0500 Date: Thu, 27 Nov 2014 11:56:03 +0100 From: Ingo Molnar To: Arnaldo Carvalho de Melo Cc: Jiri Olsa , linux-kernel@vger.kernel.org, Linus Torvalds , Andi Kleen , Corey Ashford , David Ahern , Frederic Weisbecker , Matt Fleming , Namhyung Kim , Paul Mackerras , Peter Zijlstra , Stephane Eranian Subject: Re: [PATCH] perf tools: Do not fail on processing out of order event Message-ID: <20141127105603.GA1987@gmail.com> References: <1417016371-30249-1-git-send-email-jolsa@kernel.org> <20141126154459.GD3808@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20141126154459.GD3808@redhat.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Arnaldo Carvalho de Melo wrote: > Em Wed, Nov 26, 2014 at 04:39:31PM +0100, Jiri Olsa escreveu: > > Linus reported perf report command being interrupted due to > > processing of 'out of order' event, with following error: > > > > Timestamp below last timeslice flush > > 0x5733a8 [0x28]: failed to process type: 3 > > > > I could reproduce the issue and in my case it was caused by one > > CPU (mmap) being behind during record and userspace mmap reader > > seeing the data after other CPUs data were already stored. > > > > It'd be nice to find the source of this hiccup, meanwhile I'm > > submitting change that does not kill the processing, but only > > tracks the number of out of order events and warn user. > > Works, for me, thanks for the fast response! Thanks Jiri! > > --- a/tools/perf/util/session.c > > +++ b/tools/perf/util/session.c > > @@ -533,15 +533,11 @@ int perf_session_queue_event(struct perf_session *s, union perf_event *event, > > return -ETIME; > > > > if (timestamp < oe->last_flush) { > > - WARN_ONCE(1, "Timestamp below last timeslice flush\n"); > > - > > - pr_oe_time(timestamp, "out of order event"); > > + pr_oe_time(timestamp, "out of order event\n"); > > pr_oe_time(oe->last_flush, "last flush, last_flush_type %d\n", > > oe->last_flush_type); > > > > - /* We could get out of order messages after forced flush. */ > > - if (oe->last_flush_type != OE_FLUSH__HALF) > > - return -EINVAL; > > + s->stats.nr_unordered_events++; Btw., in the forced flush case we'll get out of order events that are 'expected'. Shouldn't we count them separately and not warn about them, or so? > > + if (session->stats.nr_unordered_events != 0) { > > + ui__warning("%u out of order events recorded.\n", > > + session->stats.nr_unordered_events); > > + } Nit: I'd suggest keeping the message printout on a single line: if (session->stats.nr_unordered_events != 0) { ui__warning("%u out of order events recorded.\n", session->stats.nr_unordered_events); as IMHO the cure for this col80 linebreak checkpatch warning is worse than the disease! :-) Barring those details: Acked-by: Ingo Molnar Arnaldo, I suppose the fix will go upstream via your tree, as a pull request for v3.18 fixes? Thanks, Ingo -- 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/