From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F3CBDECDFD0 for ; Fri, 14 Sep 2018 12:19:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9F94020861 for ; Fri, 14 Sep 2018 12:19:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9F94020861 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727953AbeINRd6 (ORCPT ); Fri, 14 Sep 2018 13:33:58 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33376 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726872AbeINRd6 (ORCPT ); Fri, 14 Sep 2018 13:33:58 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 0E73C85A07; Fri, 14 Sep 2018 12:19:44 +0000 (UTC) Received: from krava (unknown [10.43.17.10]) by smtp.corp.redhat.com (Postfix) with SMTP id 5453C6A6B9; Fri, 14 Sep 2018 12:19:41 +0000 (UTC) Date: Fri, 14 Sep 2018 14:19:40 +0200 From: Jiri Olsa To: Ingo Molnar Cc: Peter Zijlstra , Namhyung Kim , Alexey Budankov , Jiri Olsa , Arnaldo Carvalho de Melo , lkml , Alexander Shishkin , Andi Kleen , kernel-team@lge.com Subject: Re: [RFCv2 00/48] perf tools: Add threads to record command Message-ID: <20180914121940.GA9737@krava> References: <20180913125450.21342-1-jolsa@kernel.org> <20180914022910.GA15146@sejong> <20180914082307.GF24224@krava> <20180914094022.GB96351@gmail.com> <20180914111528.GH24124@hirez.programming.kicks-ass.net> <20180914114725.GB17042@krava> <20180914120129.GJ24124@hirez.programming.kicks-ass.net> <20180914121307.GA98534@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180914121307.GA98534@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Fri, 14 Sep 2018 12:19:44 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 14, 2018 at 02:13:07PM +0200, Ingo Molnar wrote: > > * Peter Zijlstra wrote: > > > On Fri, Sep 14, 2018 at 01:47:25PM +0200, Jiri Olsa wrote: > > > On Fri, Sep 14, 2018 at 01:15:28PM +0200, Peter Zijlstra wrote: > > > > On Fri, Sep 14, 2018 at 11:40:22AM +0200, Ingo Molnar wrote: > > > > > In fact keeping the files separate has scalability advantages for 'perf report' and similar > > > > > parsing tools: they could read all the streams in a per-CPU fashion already, from the very > > > > > beginning. > > > > > > > > Also writing to different files from different CPUs is good for record, > > > > less contention on the inode state (which include pagecache). > > > > > > maybe I should explain a little bit more on this > > > > > > we write to different (per-cpu) files during the record, > > > and at the end of the session, we take them and store > > > them inside perf.data > > > > How long does it take to combine that? If we generated a lot of data, > > that could take a fair amount of time, no? yep.. fair amount ;-) wasn't that bad in my tests, but could be evil on some really big server > > I feel that record should not mysteriously 'hang' when it is done. It > > used to do that at some point because of that stupid .debug crap, but > > acme fixed that I think. > > Agreed - plus at the report stage it would be advantageous to be able to *read* per-cpu files > as well. > > If we do things smartly them report will create similar NUMA affinity as the record session > used. ok, separate files it is jirka