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=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,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 3DB92C433ED for ; Tue, 27 Apr 2021 19:37:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 041AB613F8 for ; Tue, 27 Apr 2021 19:37:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238526AbhD0TiB (ORCPT ); Tue, 27 Apr 2021 15:38:01 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:43018 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235661AbhD0Th4 (ORCPT ); Tue, 27 Apr 2021 15:37:56 -0400 From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1619552232; 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=Ot3CX42DdeSAWCrHpKWnb8PLwfyj5Nk4Iu25OpQHJ+o=; b=PV/CdW8tLiAAH7Ne3YiOX/ggBfcEMdH/U2/ik4DL53XI0TJHDRyWNZQUNP32JYAZv6DUsv gOAIHaWLNsv8l/+0L7BBz25kQVZ6Eij/jgBc9XqnMbrcibs/o8O8RxeQoaOcsE510Tt8Bk jQsrchfqhHM39danXhl9Pd1VR5WsilSWOd78GxJC4rm7u9D8do1VSSvYwiFczqYRNqebv7 w/fzuo+1vqI7bQrXWap0WSA7BuQ+6Z2ljwxAFOyWHjhrgw1BZi5ZRmSPmTvbNttbMTXxcT BSCh9CFY62jCRgFS9Vsh+oaTyDgUma1k/B94h950cybjgD2nOTIBd7LPivhV+g== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1619552232; 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=Ot3CX42DdeSAWCrHpKWnb8PLwfyj5Nk4Iu25OpQHJ+o=; b=elbh7KiE73tjeIgfFriSiKWEbwpfgLRdVTW287uCTJD1PJqhgTlt5vqy6/JMvzv7KTbZqu Y4DUBWFf7nntKADA== To: kernel test robot , Barry Song Cc: Ingo Molnar , LKML , lkp@lists.01.org, lkp@intel.com, ying.huang@intel.com, feng.tang@intel.com, zhengjun.xing@intel.com, x86@kernel.org Subject: Re: [genirq] cbe16f35be: will-it-scale.per_thread_ops -5.2% regression In-Reply-To: <87fszcnecr.ffs@nanos.tec.linutronix.de> References: <87fszcnecr.ffs@nanos.tec.linutronix.de> Date: Tue, 27 Apr 2021 21:37:11 +0200 Message-ID: <87czufo6xk.ffs@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 27 2021 at 13:42, Thomas Gleixner wrote: > On Tue, Apr 27 2021 at 17:00, kernel test robot wrote: >> FYI, we noticed a -5.2% regression of will-it-scale.per_thread_ops due to commit: >> >> commit: cbe16f35bee6880becca6f20d2ebf6b457148552 ("genirq: Add IRQF_NO_AUTOEN for request_irq/nmi()") >> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master > > this is the second report in the last week which makes not a lot of sense. > And this oneis makes absolutely no sense at all. > > This commit affects request_irq() and the related variants and has > exactly ZERO influence on anything related to that test case simply > because. > > I seriously have to ask the question whether this test infrastructure is > actually measuring what it claims to measure. > > As this commit clearly _cannot_ have the 'measured' side effect, this > points to some serious issue in the tests or the test infrastructure > itself. Just to illustrate the issue: I ran the will-it-scale getppid1 test manually against plain v5.12 and against v5.12 + cherrypicked cbe16f35be, i.e. the "offending" commit. The result for a full run is just in the noise: average: < 0.1% minimum: -0.22% maximum: 0.29% IOW very far away from -5.2%. That's an order of magnitude off. And no, I'm not going to run that lkp-test muck simply because it's unusable and the test result of will-it-scale itself is clear enough. Thanks, tglx