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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CF522C19F2C for ; Wed, 3 Aug 2022 09:52:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237898AbiHCJwP (ORCPT ); Wed, 3 Aug 2022 05:52:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33680 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237619AbiHCJvp (ORCPT ); Wed, 3 Aug 2022 05:51:45 -0400 Received: from mail-wr1-x435.google.com (mail-wr1-x435.google.com [IPv6:2a00:1450:4864:20::435]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8974528703; Wed, 3 Aug 2022 02:51:18 -0700 (PDT) Received: by mail-wr1-x435.google.com with SMTP id z16so20826558wrh.12; Wed, 03 Aug 2022 02:51:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=OsTucAz3U2NvqKccpgYeXLddbVzfXi3zTHHQDqTnHd8=; b=MZNgR4E+mQQWms7zLvTBVlgulKGD9neWeW4xIY4nszWcPHES988BnKNzgM8tQw4Z3z 8NssehEEpEw6D4LUiwwpGm+k2B0/BM9sCPU6bz0tZlMfab9DViXvTSkv11iP+7QEKXeQ t1IJHebvNXg9rJslokkuRLcyrcGPs913Y/tOv5NUxtn7X7lSmhU2S75ZsqMKY/Qa3t5F yllFyZPIqnBBBaeDaxldq5dIiKC9OlUFx6gdQbp7Y32sC8tZ4M/HRfxE3RwI6FQwFGSy qQECJvxSNBsaNy7A1Xdvx8iv/LczMMeIwKSBdp2EFXeV5TUF1z8VOkFCxnbnqdWpkIrd nZTA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=OsTucAz3U2NvqKccpgYeXLddbVzfXi3zTHHQDqTnHd8=; b=OXA+pV9DR+3BSLnXkVAOl2MEvbKwnR+tEXDaXUionzAnOWr6O8iHlIwfkq4bTB5IIe tVv2YmOD61y2Fd/8OqmTrtZKgCEe6/p56w3zBTCfbCENXKMnVUFPMV4N6dClLKpT30c8 8lH2pdWrntI1/LufeoBWvHR67ZxVPWRtUQNrw00bJzxJS97/rUCrLhGQk94Pddrw+ndK mg0LrODsyeR/evgg8uOLfx0N319u90OBXGyaZc94nuAFhdK+sJrAD0wbdeACvU9Bt4J4 iQCa6IHUOwtxKTPDQtOB/cMU2Hyk5tzgEQCvOMfEsSbN73WoJkPvk3abpk6+Gn0UfRec eCJQ== X-Gm-Message-State: ACgBeo12TlCuGfMQyz4e0fBsR+A52RShtwdKx+rEgDZN1uiQRTufpKXI L6eexZNdH8aD7NYARAV65cfIzUi59DI= X-Google-Smtp-Source: AA6agR7nRoc9deiV7oVvXs/bFBj5HKVUwDBvg4NqDlkkD/o4gxkgzoH7DaDcGw+gFtlvsTZQOVv/yQ== X-Received: by 2002:a05:6000:1869:b0:220:639b:8337 with SMTP id d9-20020a056000186900b00220639b8337mr8331794wri.572.1659520277173; Wed, 03 Aug 2022 02:51:17 -0700 (PDT) Received: from gmail.com (84-236-113-167.pool.digikabel.hu. [84.236.113.167]) by smtp.gmail.com with ESMTPSA id u11-20020a05600c19cb00b003a302fb9df7sm2022042wmq.21.2022.08.03.02.51.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 03 Aug 2022 02:51:16 -0700 (PDT) Sender: Ingo Molnar Date: Wed, 3 Aug 2022 11:51:14 +0200 From: Ingo Molnar To: Namhyung Kim Cc: Arnaldo Carvalho de Melo , Jiri Olsa , Peter Zijlstra , LKML , Ian Rogers , linux-perf-users@vger.kernel.org, Will Deacon , Waiman Long , Boqun Feng , Davidlohr Bueso Subject: Re: [PATCHSET 0/6] perf lock: Add contention subcommand (v1) Message-ID: References: <20220721043644.153718-1-namhyung@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220721043644.153718-1-namhyung@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Namhyung Kim wrote: > Hello, > > It's to add a new subcommand 'contention' (shortly 'con') to perf lock. > > The new subcommand is to handle the new lock:contention_{begin,end} > tracepoints and shows lock type and caller address like below: > > $ perf lock contention > contended total wait max wait avg wait type caller > > 238 1.41 ms 29.20 us 5.94 us spinlock update_blocked_averages+0x4c > 1 902.08 us 902.08 us 902.08 us rwsem:R do_user_addr_fault+0x1dd > 81 330.30 us 17.24 us 4.08 us spinlock _nohz_idle_balance+0x172 > 2 89.54 us 61.26 us 44.77 us spinlock do_anonymous_page+0x16d > 24 78.36 us 12.27 us 3.27 us mutex pipe_read+0x56 > 2 71.58 us 59.56 us 35.79 us spinlock __handle_mm_fault+0x6aa > 6 25.68 us 6.89 us 4.28 us spinlock do_idle+0x28d > 1 18.46 us 18.46 us 18.46 us rtmutex exec_fw_cmd+0x21b > 3 15.25 us 6.26 us 5.08 us spinlock tick_do_update_jiffies64+0x2c > ... Wouldn't it also be useful to display a lock contention percentage value, the ratio of fastpath vs. contended/wait events? That's usually the first-approximation metric to see how contended different locks are, and the average wait time quantifies it. Thanks, Ingo