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 129E0C04A94 for ; Wed, 16 Aug 2023 09:21:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243284AbjHPJU6 (ORCPT ); Wed, 16 Aug 2023 05:20:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60628 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243287AbjHPJUm (ORCPT ); Wed, 16 Aug 2023 05:20:42 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 560A11FE1 for ; Wed, 16 Aug 2023 02:20:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=52OUPFqOh3y1o3XJS8UWl+mBu8nIpC1XrgJkA0+bGf8=; b=WnF+CinMKjZPkOLqKsaxtu8l4d VkKvFEUgxxltxDk96IlHb9fCzZt1B5wKGXuFmYvMj5SEOb8QM+I3ROcVX+uMZMnJVxzXZKTxlpzvQ voGupV3DrjfqCd+DmJoWAT5t+sxlP1ZRIzrO/PqYh7oXsm4i0IZM2pI141MqXIqTsMyOMLL/J11Yl MkOfvjBcxBYzbox3JJPAgsLQXj0nWFEUJuZPjTykq/9groUeH7bbopOMeqTe1JK9WobJdm/Thw/Fi sgw+n0A7Q7Y3/fACuH/Dp3rnjB8iUzuCu+qxY43KWbn957bp/m5XZacTJpCmOq6c4EGpEJLZma9fA y3ySKaLw==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1qWChd-00DnHN-OB; Wed, 16 Aug 2023 09:20:33 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 59C1D300222; Wed, 16 Aug 2023 11:20:33 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 423A32C8D7753; Wed, 16 Aug 2023 11:20:33 +0200 (CEST) Date: Wed, 16 Aug 2023 11:20:33 +0200 From: Peter Zijlstra To: Chen Yu Cc: kernel test robot , oe-lkp@lists.linux.dev, lkp@intel.com, linux-kernel@vger.kernel.org, x86@kernel.org, Ingo Molnar , Mike Galbraith Subject: Re: [tip:sched/eevdf] [sched/fair] e0c2ff903c: phoronix-test-suite.blogbench.Write.final_score -34.8% regression Message-ID: <20230816092033.GB980931@hirez.programming.kicks-ass.net> References: <202308101628.7af4631a-oliver.sang@intel.com> <20230814132935.GK776869@hirez.programming.kicks-ass.net> 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 Wed, Aug 16, 2023 at 11:40:33AM +0800, Chen Yu wrote: > > Are these wakeup preemptions typically on runqueues that have only a > > single other task? > > > > There are 112 groups of hackbench waker/wakee on a 112 CPUs system. > Each group has 1 waker and 20 wakees. It seems that there are more than 1 > other task on each runqueue. I collected the statistics below. Oh, I thought we were still talking about $subject benchmark. Yeah, hackbench has a ton of tasks. > According to above data, maybe comparing the deadline does not take much > effect in this case(per 1). Yeah, I stuck a trace_printk() in last night and quicly realized the lag is on the same order of request size, which then totally makes the whole thing moot.