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=-12.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 057DBC636C9 for ; Mon, 19 Jul 2021 21:43:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CB3556128A for ; Mon, 19 Jul 2021 21:43:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348931AbhGSU5w (ORCPT ); Mon, 19 Jul 2021 16:57:52 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:32561 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1387840AbhGSUgU (ORCPT ); Mon, 19 Jul 2021 16:36:20 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1626729376; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=CZbqAx8RCbkxkOvue3VbFWnAjITofkdFcSi0ebBpg7c=; b=LopMR2h4/mKBTIbo5vFuos2vIBXsI137sPQ+oF/lIVKwA6+8Y+OdfdkWAPgl5bZWMdIGFB zovyWtaIu4JeUMtHF+COzZ8y+FlqLFUChCDFLgdI8wtNrXvcjtVXfoLs06CyFcFc4nqsia mODia137yNLlutyVyX6dUSjMIk+SLiQ= Received: from mail-ej1-f69.google.com (mail-ej1-f69.google.com [209.85.218.69]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-486-B3QSsoB5ONW2mmiNUk2y6g-1; Mon, 19 Jul 2021 17:13:31 -0400 X-MC-Unique: B3QSsoB5ONW2mmiNUk2y6g-1 Received: by mail-ej1-f69.google.com with SMTP id bl17-20020a170906c251b029052292d7c3b4so5929792ejb.9 for ; Mon, 19 Jul 2021 14:13:31 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=CZbqAx8RCbkxkOvue3VbFWnAjITofkdFcSi0ebBpg7c=; b=FUJuYy+vQ0rBOCNp0lomuJyZhUi/xpNMLgTcY54OY0wHQEC+Xxg9XnQNHMemEketfE ncbwGHXX8Kr4WHM4QXPebvRGLQGYfgdLwoycTy/bbxfo7wPoeRhEGBlphGPddlcM1iNH 1uzhvdc8Er1NS4rf7TfxbTqKOFlrU6cy1iLqOH0YrxMHXzxQDKQKtwOg/HonpGbZvsBl ihmbR3njZ6DzmmpB9piWfId58EgM4WbUOyVuNnxHzH7AvdvmMVZrARsxYaQtHfneDuMY lVFfINbqNtn5tglVHmzdruf9+Kh83RQc+Tcye0a+0pQE2ml04eohwfiN8Rv2fdnH8URk yoUQ== X-Gm-Message-State: AOAM531N72fijNBDrdaG0DlYpbOWifRVk/4oxeuTYyDlqhUSSr3Filf4 RcTlx1KG7FwvbDKrg9AdjDpEUz+8FFSjY7SMzeYgL4Uz0gl1RVkrdUf+sBFYTdVQ5oOmQDJkDyZ bDsmHJVxKInOpSuNBhp32XEMO X-Received: by 2002:a17:907:1c9f:: with SMTP id nb31mr29626539ejc.342.1626729209742; Mon, 19 Jul 2021 14:13:29 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyZcbdUplE0ZM5hFo76QHPnaJkulHVLBuERYtpqhzmRgCab8byCiyP4+jrQdhO9FmizVgN1RQ== X-Received: by 2002:a17:907:1c9f:: with SMTP id nb31mr29626521ejc.342.1626729209530; Mon, 19 Jul 2021 14:13:29 -0700 (PDT) Received: from krava ([83.240.60.59]) by smtp.gmail.com with ESMTPSA id jw8sm6284226ejc.60.2021.07.19.14.13.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 19 Jul 2021 14:13:29 -0700 (PDT) Date: Mon, 19 Jul 2021 23:13:27 +0200 From: Jiri Olsa To: Riccardo Mancini Cc: Arnaldo Carvalho de Melo , Ian Rogers , Namhyung Kim , Peter Zijlstra , Ingo Molnar , Mark Rutland , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: Re: [RFC PATCH 00/10] perf: add workqueue library and use it in synthetic-events Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 13, 2021 at 02:11:11PM +0200, Riccardo Mancini wrote: > This patchset introduces a new utility library inside perf/util, which > provides a work queue abstraction, which loosely follows the Kernel > workqueue API. > > The workqueue abstraction is made up by two components: > - threadpool: which takes care of managing a pool of threads. It is > inspired by the prototype for threaded trace in perf-record from Alexey: > https://lore.kernel.org/lkml/cover.1625227739.git.alexey.v.bayduraev@linux.intel.com/ > - workqueue: manages a shared queue and provides the workers implementation. > > On top of the workqueue, a simple parallel-for utility is implemented > which is then showcased in synthetic-events.c, replacing the previous > manual pthread-created threads. > > Through some experiments with perf bench, I can see how the new > workqueue has a higher overhead compared to manual creation of threads, > but is able to more effectively partition work among threads, yielding > a better result with more threads. > Furthermore, the overhead could be configured by changing the > `work_size` (currently 1), aka the number of dirents that are > processed by a thread before grabbing a lock to get the new work item. > I experimented with different sizes but, while bigger sizes reduce overhead > as expected, they do not scale as well to more threads. > > I tried to keep the patchset as simple as possible, deferring possible > improvements and features to future work. > Naming a few: > - in order to achieve a better performance, we could consider using > work-stealing instead of a common queue. > - affinities in the thread pool, as in Alexey prototype for > perf-record. Doing so would enable reusing the same threadpool for > different purposes (evlist open, threaded trace, synthetic threads), > avoiding having to spin up threads multiple times. > - resizable threadpool, e.g. for lazy spawining of threads. > > @Arnaldo > Since I wanted the workqueue to provide a similar API to the Kernel's > workqueue, I followed the naming style I found there, instead of the > usual object__method style that is typically found in perf. > Let me know if you'd like me to follow perf style instead. > > Thanks, > Riccardo > > Riccardo Mancini (10): > perf workqueue: threadpool creation and destruction > perf tests: add test for workqueue > perf workqueue: add threadpool start and stop functions > perf workqueue: add threadpool execute and wait functions > perf workqueue: add sparse annotation header > perf workqueue: introduce workqueue struct > perf workqueue: implement worker thread and management > perf workqueue: add queue_work and flush_workqueue functions > perf workqueue: add utility to execute a for loop in parallel > perf synthetic-events: use workqueue parallel_for looks great, would it make sense to put this to libperf? jirka > > tools/perf/tests/Build | 1 + > tools/perf/tests/builtin-test.c | 9 + > tools/perf/tests/tests.h | 3 + > tools/perf/tests/workqueue.c | 453 +++++++++++++++++ > tools/perf/util/Build | 1 + > tools/perf/util/synthetic-events.c | 131 +++-- > tools/perf/util/workqueue/Build | 2 + > tools/perf/util/workqueue/sparse.h | 21 + > tools/perf/util/workqueue/threadpool.c | 516 ++++++++++++++++++++ > tools/perf/util/workqueue/threadpool.h | 29 ++ > tools/perf/util/workqueue/workqueue.c | 642 +++++++++++++++++++++++++ > tools/perf/util/workqueue/workqueue.h | 38 ++ > 12 files changed, 1771 insertions(+), 75 deletions(-) > create mode 100644 tools/perf/tests/workqueue.c > create mode 100644 tools/perf/util/workqueue/Build > create mode 100644 tools/perf/util/workqueue/sparse.h > create mode 100644 tools/perf/util/workqueue/threadpool.c > create mode 100644 tools/perf/util/workqueue/threadpool.h > create mode 100644 tools/perf/util/workqueue/workqueue.c > create mode 100644 tools/perf/util/workqueue/workqueue.h > > -- > 2.31.1 >