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=-2.1 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, 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 4019DFC6182 for ; Fri, 14 Sep 2018 12:01:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CA19720881 for ; Fri, 14 Sep 2018 12:01:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="IxTw6N2b" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CA19720881 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org 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 S1728132AbeINRPp (ORCPT ); Fri, 14 Sep 2018 13:15:45 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:39784 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727134AbeINRPp (ORCPT ); Fri, 14 Sep 2018 13:15:45 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=JasgV8QD5xXOe86E0sCadXzIoKd4fLwFxGn3HK5uZbo=; b=IxTw6N2bBV7sV0pNDxeE/MwRe ENj6hA6k6cykmRmRwKNk3A8BIy43lPaFCR2zfcIOnHo/z6xhVqXEBXuXBbzCj2taeyfIf7lMqP2aw qVHZWv2HPaWW3Yn+3K7OaE/2exUoDfexAc1cJnnZDJkMpUFaSGz2sPXDZe4Jr6c7H9tVuA0Rzdt0V YdDQXZSP1nTBxeJFMiDrm8a0cD8Ky6+k716+KLEG44QYUKx3VeeaygJJrNYXEAy7C7xb3w7sxFMmO 6z76kYNk89svX7K2+fxgMZYsly7AJN9KdIfEPOXd84q6ZtIX/ULHbGzLhU52YpW01zXPHBdZ/3NXp GcM1Bijfg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1g0mmx-0000P5-BK; Fri, 14 Sep 2018 12:01:31 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id B537F202B2E3B; Fri, 14 Sep 2018 14:01:29 +0200 (CEST) Date: Fri, 14 Sep 2018 14:01:29 +0200 From: Peter Zijlstra To: Jiri Olsa 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: <20180914120129.GJ24124@hirez.programming.kicks-ass.net> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180914114725.GB17042@krava> User-Agent: Mutt/1.10.0 (2018-05-17) 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 01:47:25PM +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? 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.