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 96BCDC43382 for ; Wed, 26 Sep 2018 06:23:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4D9F92086E for ; Wed, 26 Sep 2018 06:23:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4D9F92086E 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 S1727175AbeIZMep (ORCPT ); Wed, 26 Sep 2018 08:34:45 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58766 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726595AbeIZMep (ORCPT ); Wed, 26 Sep 2018 08:34:45 -0400 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.24]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 12817308A94E; Wed, 26 Sep 2018 06:23:26 +0000 (UTC) Received: from krava (ovpn-204-149.brq.redhat.com [10.40.204.149]) by smtp.corp.redhat.com (Postfix) with SMTP id 6564C308BE75; Wed, 26 Sep 2018 06:23:19 +0000 (UTC) Date: Wed, 26 Sep 2018 08:23:17 +0200 From: Jiri Olsa To: Arnaldo Carvalho de Melo Cc: Namhyung Kim , Jiri Olsa , lkml , Ingo Molnar , Alexander Shishkin , Peter Zijlstra , Andi Kleen , Alexey Budankov , kernel-team@lge.com Subject: Re: [PATCH 47/48] perf record: Spread maps for --threads option Message-ID: <20180926062317.GA8610@krava> References: <20180913125450.21342-1-jolsa@kernel.org> <20180913125450.21342-48-jolsa@kernel.org> <20180917114048.GF18395@sejong> <20180923194432.GH30923@krava> <20180924142254.GB4640@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180924142254.GB4640@kernel.org> User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.24 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.41]); Wed, 26 Sep 2018 06:23:26 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 24, 2018 at 11:22:54AM -0300, Arnaldo Carvalho de Melo wrote: > Em Sun, Sep 23, 2018 at 09:44:32PM +0200, Jiri Olsa escreveu: > > On Mon, Sep 17, 2018 at 08:40:48PM +0900, Namhyung Kim wrote: > > > On Thu, Sep 13, 2018 at 02:54:49PM +0200, Jiri Olsa wrote: > > > > Currently we assign all maps to main thread. Adding > > > > code that spreads maps for --threads option. > > > > > > > > For --thread option we create as many threads as there > > > > are memory maps in evlist, which is the number of CPUs > > > > in the system or CPUs we monitor. Each thread gets a > > > > single data mmap to read. > > > > > > > > In addition we have also same amount of tracking mmaps > > > > for auxiliary events which we don't create special thread > > > > for. Instead we assign the to the main thread, because > > > > there's not much traffic expected there. > > > > > > > > The assignment is visible from --thread-stats output: > > > > > > > > pid write poll skip maps (size 20K) > > > > 1s 9770 144B 1 0 19K 19K 19K 18K 19K > > > > 9772 0B 1 0 18K > > > > 9773 0B 1 0 19K > > > > 9774 0B 1 0 19K > > > > > > > > There are 5 maps for thread 9770 (1 data map and 4 auxiliary) > > > > and one data map for every other thread. Each thread writes > > > > data to the separate data file. > > > > > > Hmm.. not sure it'll work well for large machines with 1000+ cpus. > > > What about giving each thread a data mmap and a tracking mmap? > > > > well currently we store the tracking data in single file, > > thats why we need just one thread to write them down > > I agree with Namhyung, with a slight difference: perhaps we should set > perf_event_attr.mmap on one of the events of the per-cpu mmap, that way > we don't need that dummy event, right? currently it's all based on having tracking data separated in single file which is read/processed first, so when we read the sample data files, we can read them separately, because we have the tracking data ready > > > with the *_time API, we should be able to properly read the > > tracking data separately for each cpu > > That may end up making the *_time API not needed (assuming the kernel > keeps the per-cpu mmap events in order, barring that, using the > ordered_events in batches, prior to consuming the events) and would help > with things like 'perf top' and 'perf trace', that want to consume > events right away. if we dont want to use *_by_time API, we need to find a way to sort evevrything out before we start processing.. and that seems too costly to me jirka