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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,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 E51F3ECDFD0 for ; Fri, 14 Sep 2018 11:47:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8FDA620853 for ; Fri, 14 Sep 2018 11:47:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8FDA620853 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 S1727944AbeINRBg (ORCPT ); Fri, 14 Sep 2018 13:01:36 -0400 Received: from mx1.redhat.com ([209.132.183.28]:37314 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727403AbeINRBg (ORCPT ); Fri, 14 Sep 2018 13:01:36 -0400 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.25]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B599C30833C4; Fri, 14 Sep 2018 11:47:28 +0000 (UTC) Received: from krava (unknown [10.43.17.10]) by smtp.corp.redhat.com (Postfix) with SMTP id 6F2082010D07; Fri, 14 Sep 2018 11:47:26 +0000 (UTC) Date: Fri, 14 Sep 2018 13:47:25 +0200 From: Jiri Olsa To: Peter Zijlstra Cc: Ingo Molnar , 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: <20180914114725.GB17042@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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180914111528.GH24124@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.25 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.44]); Fri, 14 Sep 2018 11:47:29 +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 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 I don't mind having the directory instead, however we are talking about small amount of code allowing us to keep the data in single file.. we can always leave it to a special command line option ;-) jirka