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=-3.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=no 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 C5EC7C432C3 for ; Wed, 20 Nov 2019 19:29:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 96B9420715 for ; Wed, 20 Nov 2019 19:29:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="R7zqRjHP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727756AbfKTT3O (ORCPT ); Wed, 20 Nov 2019 14:29:14 -0500 Received: from mail-lj1-f194.google.com ([209.85.208.194]:35876 "EHLO mail-lj1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726440AbfKTT3N (ORCPT ); Wed, 20 Nov 2019 14:29:13 -0500 Received: by mail-lj1-f194.google.com with SMTP id k15so444715lja.3 for ; Wed, 20 Nov 2019 11:29:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=B8mggtxU1zp4JDBupngVAB3B8vB3qNT6+jtDLAhJwfY=; b=R7zqRjHPN2+U6QPltce6KNHzU2cvypcB1dU0saO7eF1M2zmzXX7bzDZ7uBYN5h71bt GpD0BTJrnBfbQxo0/wG4pLANiM4Qn4/6r0sRCj5Cp3CWg7d15y8ctdEDKDfEkMRqrfgG YBlXvVZd3A9HSjoGPy9HXTRRYNn83GbGlUJUZthoT0p8hHIeu1njWaB8qA/Tt4qGgdXl brKse3KdVXYJvz6i2simx7Y4evr5s1ofIDwGA4FafS1FWoZvX8hWbxtl6l5gvgasFTzQ i6X8LDJvYdq90JHeTB0mrYKXm+sHT2VZ15sYx0z5opEu+IZIXXxvyIcq19kzsGh/+L6q hP7w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=B8mggtxU1zp4JDBupngVAB3B8vB3qNT6+jtDLAhJwfY=; b=VmR9mdFRcPsrA3V5KqBURMdgeYlGlI5F1+dq9EqteOhYbbb18319WrSJZ3vtjNtgTZ OyOf9DHcvOMatumwHzEWznqHyEBi+2tiPQeryeB0U1R+l/xTzI8MEMheBqVLwozXktU2 8sw4KItkuGDBGSMwfkgLcQU/veJHB7VGw1IKwkbX2Aej1CyC7wSARegNvOTHXMIqRFwF Rspd/HK/5E1WYpYX3aLBr90L6w8wcyByrEEYL46mIFq/SV0dy3X3uiTY+rxKuXQUWuw8 4LXAUhHCZYAlC1BtsTGRgODmJnkhE/9mdCsv0iPL4E40G/8F3CMf0fRvhjXHTE1APg6V d3Sw== X-Gm-Message-State: APjAAAUhbUE1RN1h2vvV5tqbzaBAecse8QammBo7esf4IF/zyewhDRv8 1XgHBMmkVLk4RIXmq8nD1SX5wqJAtl48wzoA7ROCgw== X-Google-Smtp-Source: APXvYqx2G6y4tjddPf3ANE9ZbeXC93VOkJVataHNoGp2fl4B41RC8K2QNrPppdRg7AWc5+ERDXbTHlws0MCPCU+RNF4= X-Received: by 2002:a2e:982:: with SMTP id 124mr4385167ljj.48.1574278149099; Wed, 20 Nov 2019 11:29:09 -0800 (PST) MIME-Version: 1.0 References: <1571405198-27570-1-git-send-email-vincent.guittot@linaro.org> <1571405198-27570-12-git-send-email-vincent.guittot@linaro.org> <20191120115844.scli3gprgd5vvlt4@e107158-lin.cambridge.arm.com> <20191120173431.b7e4jbq44mjletfe@e107158-lin.cambridge.arm.com> <20191120181002.lh7vukjm2ifhysbc@e107158-lin.cambridge.arm.com> <20191120182731.z2sh5ju7uir5s3cp@e107158-lin.cambridge.arm.com> In-Reply-To: <20191120182731.z2sh5ju7uir5s3cp@e107158-lin.cambridge.arm.com> From: Vincent Guittot Date: Wed, 20 Nov 2019 20:28:57 +0100 Message-ID: Subject: Re: [PATCH v4 11/11] sched/fair: rework find_idlest_group To: Qais Yousef Cc: linux-kernel , Ingo Molnar , Peter Zijlstra , Phil Auld , Valentin Schneider , Srikar Dronamraju , Quentin Perret , Dietmar Eggemann , Morten Rasmussen , Hillf Danton , Parth Shah , Rik van Riel Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 20 Nov 2019 at 19:27, Qais Yousef wrote: > > On 11/20/19 19:20, Vincent Guittot wrote: > > On Wed, 20 Nov 2019 at 19:10, Qais Yousef wrote: > > > > > > On 11/20/19 18:43, Vincent Guittot wrote: > > > > On Wed, 20 Nov 2019 at 18:34, Qais Yousef wrote: > > > > > > > > > > On 11/20/19 17:53, Vincent Guittot wrote: > > > > > > On Wed, 20 Nov 2019 at 14:21, Vincent Guittot > > > > > > wrote: > > > > > > > > > > > > > > Hi Qais, > > > > > > > > > > > > > > On Wed, 20 Nov 2019 at 12:58, Qais Yousef wrote: > > > > > > > > > > > > > > > > Hi Vincent > > > > > > > > > > > > > > > > On 10/18/19 15:26, Vincent Guittot wrote: > > > > > > > > > The slow wake up path computes per sched_group statisics to select the > > > > > > > > > idlest group, which is quite similar to what load_balance() is doing > > > > > > > > > for selecting busiest group. Rework find_idlest_group() to classify the > > > > > > > > > sched_group and select the idlest one following the same steps as > > > > > > > > > load_balance(). > > > > > > > > > > > > > > > > > > Signed-off-by: Vincent Guittot > > > > > > > > > --- > > > > > > > > > > > > > > > > LTP test has caught a regression in perf_event_open02 test on linux-next and I > > > > > > > > bisected it to this patch. > > > > > > > > > > > > > > > > That is checking out next-20191119 tag and reverting this patch on top the test > > > > > > > > passes. Without the revert the test fails. > > > > > > > > > > > > I haven't tried linux-next yet but LTP test is passed with > > > > > > tip/sched/core, which includes this patch, on hikey960 which is arm64 > > > > > > too. > > > > > > > > > > > > Have you tried tip/sched/core on your juno ? this could help to > > > > > > understand if it's only for juno or if this patch interact with > > > > > > another branch merged in linux next > > > > > > > > > > Okay will give it a go. But out of curiosity, what is the output of your run? > > > > > > > > > > While bisecting on linux-next I noticed that at some point the test was > > > > > passing but all the read values were 0. At some point I started seeing > > > > > none-zero values. > > > > > > > > for tip/sched/core > > > > linaro@linaro-developer:~/ltp/testcases/kernel/syscalls/perf_event_open$ > > > > sudo ./perf_event_open02 > > > > perf_event_open02 0 TINFO : overall task clock: 63724479 > > > > perf_event_open02 0 TINFO : hw sum: 1800900992, task clock sum: 382170311 > > > > perf_event_open02 0 TINFO : ratio: 5.997229 > > > > perf_event_open02 1 TPASS : test passed > > > > > > > > for next-2019119 > > > > ~/ltp/testcases/kernel/syscalls/perf_event_open$ sudo ./perf_event_open02 -v > > > > at iteration:0 value:0 time_enabled:69795312 time_running:0 > > > > perf_event_open02 0 TINFO : overall task clock: 63582292 > > > > perf_event_open02 0 TINFO : hw sum: 0, task clock sum: 0 > > > > hw counters: 0 0 0 0 > > > > task clock counters: 0 0 0 0 > > > > perf_event_open02 0 TINFO : ratio: 0.000000 > > > > perf_event_open02 1 TPASS : test passed > > > > > > Okay that is weird. But ratio, hw sum, task clock sum are all 0 in your > > > next-20191119. I'm not sure why the counters return 0 sometimes - is it > > > dependent on some option or a bug somewhere. > > > > > > I just did another run and it failed for me (building with defconfig) > > > > > > # uname -a > > > Linux buildroot 5.4.0-rc8-next-20191119 #72 SMP PREEMPT Wed Nov 20 17:57:48 GMT 2019 aarch64 GNU/Linux > > > > > > # ./perf_event_open02 -v > > > at iteration:0 value:260700250 time_enabled:172739760 time_running:144956600 > > > perf_event_open02 0 TINFO : overall task clock: 166915220 > > > perf_event_open02 0 TINFO : hw sum: 1200718268, task clock sum: 667621320 > > > hw counters: 300179051 300179395 300179739 300180083 > > > task clock counters: 166906620 166906200 166905160 166903340 > > > perf_event_open02 0 TINFO : ratio: 3.999763 > > > perf_event_open02 0 TINFO : nhw: 0.000100 > > > perf_event_open02 1 TFAIL : perf_event_open02.c:370: test failed (ratio was greater than ) > > > > > > It is a funny one for sure. I haven't tried tip/sched/core yet. > > > > I confirm that on next-20191119, hw counters always return 0 > > but on tip/sched/core which has this patch and v5.4-rc7 which has not, > > the hw counters are always different from 0 > > It's the other way around for me. tip/sched/core returns 0 hw counters. I tried > enabling coresight; that had no effect. Nor copying the .config that failed > from linux-next to tip/sched/core. I'm not sure what's the dependency/breakage > :-/ I run few more tests and i can get either hw counter with 0 or not. The main difference is on which CPU it runs: either big or little little return always 0 and big always non-zero value on v5.4-rc7 and tip/sched/core, cpu0-3 return 0 and other non zeroa but on next, it's the opposite cpu0-3 return non zero ratio Could you try to run the test with taskset to run it on big or little ? > > -- > Qais Yousef > > > > > on v5.4-rc7 i have got the same ratio : > > linaro@linaro-developer:~/ltp/testcases/kernel/syscalls/perf_event_open$ > > sudo ./perf_event_open02 -v > > at iteration:0 value:300157088 time_enabled:80641145 time_running:80641145 > > at iteration:1 value:300100129 time_enabled:63572917 time_running:63572917 > > at iteration:2 value:300100885 time_enabled:63569271 time_running:63569271 > > at iteration:3 value:300103998 time_enabled:63573437 time_running:63573437 > > at iteration:4 value:300101477 time_enabled:63571875 time_running:63571875 > > at iteration:5 value:300100698 time_enabled:63569791 time_running:63569791 > > at iteration:6 value:245252526 time_enabled:63650520 time_running:52012500 > > perf_event_open02 0 TINFO : overall task clock: 63717187 > > perf_event_open02 0 TINFO : hw sum: 1800857435, task clock sum: 382156248 > > hw counters: 149326575 150152481 169006047 187845928 206684169 > > 224693333 206543358 187716226 168865909 150023409 > > task clock counters: 31694792 31870834 35868749 39866666 43863541 > > 47685936 43822396 39826042 35828125 31829167 > > perf_event_open02 0 TINFO : ratio: 5.997695 > > perf_event_open02 1 TPASS : test passed