Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752896Ab0K3OCV (ORCPT ); Tue, 30 Nov 2010 09:02:21 -0500 Received: from mail-yw0-f46.google.com ([209.85.213.46]:58860 "EHLO mail-yw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752783Ab0K3OCS (ORCPT ); Tue, 30 Nov 2010 09:02:18 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:x-url:user-agent; b=WZmwu8Z4Z/bZ+ZDN1r19BQAjUi3frb2IPizzHtik7rJ+ngRCYNYbJhz1V2luxdI74v MGOTYT8SAHImEt3ZG2AeMsmgvJbLLR8mareNGB5U97D8Kkx5ceJtJt1k9R6UyVgRemeW oPZzakIxlEUQ1QWVI2EhIg6PGWspLy5/tAtcs= Date: Tue, 30 Nov 2010 12:02:13 -0200 From: Arnaldo Carvalho de Melo To: Ian Munsie Cc: Peter Zijlstra , linux-kernel , Paul Mackerras , Ingo Molnar Subject: Re: [PATCH 3/6] perf: Add timestamp to COMM and MMAP events Message-ID: <20101130140213.GB9217@ghostprotocols.net> References: <1290490544-14349-1-git-send-email-imunsie@au1.ibm.com> <1290490544-14349-4-git-send-email-imunsie@au1.ibm.com> <1290510512.2072.387.camel@laptop> <20101123124121.GA11101@ghostprotocols.net> <20101125154718.GE15875@ghostprotocols.net> <1291009409-sup-4332@au1.ibm.com> <1291031690.32004.20.camel@laptop> <1291073899-sup-7083@au1.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1291073899-sup-7083@au1.ibm.com> X-Url: http://acmel.wordpress.com 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 Content-Length: 1842 Lines: 38 Em Tue, Nov 30, 2010 at 10:45:40AM +1100, Ian Munsie escreveu: > Excerpts from Peter Zijlstra's message of Mon Nov 29 22:54:50 +1100 2010: > > On Mon, 2010-11-29 at 17:06 +1100, Ian Munsie wrote: > > > This goes away if PERF_SAMPLE_CPU is added to the mix so that the > > > timestamps are offset from the first event of *their* CPU, > > > otherwise time-epoch can go negative, as it has done here. > > How does that happen, I though the power7 sched_clock() was fully > > synchronized and monotonic across all cores? > Oh the timestamps coming from the kernel are fine, I should have been > clearer in my email. This bug is purely restricted to the userspace code > that prints them out - in the perf_session__print_tstamp function. It > tries to print the timestamps out so that they start at 0 and if it > doesn't know what CPU the events came from it uses the very first event > it sees as epoch, but at the moment that is not necessarily going to be > the earliest event. > Thinking about it overnight, I realise that this should also go away if > we sort them before printing things out at all, which is exactly what > I'm proposing to do in my patches. I removed that in the current version of this patch series: http://git.kernel.org/?p=linux/kernel/git/acme/linux-2.6.git;a=shortlog;h=refs/heads/perf/sample_id_all.v3 Now I'm just testing if a new perf.data file can be processed just fine by older tools (not possible in the sample_id_all.v1 series) and other combinations of older kernels with the new tool. Probably I'll fold two patches and then submit for review. - Arnaldo -- 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/