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 6BA35C54EE9 for ; Fri, 16 Sep 2022 11:45:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229772AbiIPLph (ORCPT ); Fri, 16 Sep 2022 07:45:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57108 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229757AbiIPLpf (ORCPT ); Fri, 16 Sep 2022 07:45:35 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3E80141D33 for ; Fri, 16 Sep 2022 04:45:31 -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=jJ/gfyFsT9QvO7TRnbdF1ML/8klCoLRCeK881VSe+pg=; b=WJzoIdT2ss0o+vZVkT6JrW2kA7 5gZV8W2WYisd8W65uD8w7+DM3R05+ZSQDlmWDI9gUGfKFCcTOfvwY2l2NaoEAq5zl2g4Hjfoadquv adit7KgcYe9nHxpIjijPDQT056eTtqFOEC3VqMPPCgCKcmlKsHIpX0YijqzVv8TOVFLd1DK3zEcxM mezxVyHChXcYhVxO2wcMzL++5FGusgjiLbrvlF5+DIrKw18IjYz3jmD84vlCnVjrFXwUy6zONkQJJ H8xqzH0ZBtiJc0HOtoGr7oz2Zt4TpcdiqafohaP/S5Qpb6FybOE5ismQeND796g6ZWCUmX/hDhsrX 0sRX4/Sg==; 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 1oZ9mL-0029iU-JY; Fri, 16 Sep 2022 11:45:05 +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) server-digest SHA256) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id D7861300342; Fri, 16 Sep 2022 13:45:00 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id B19CE201A0BBA; Fri, 16 Sep 2022 13:45:00 +0200 (CEST) Date: Fri, 16 Sep 2022 13:45:00 +0200 From: Peter Zijlstra To: Chen Yu Cc: Vincent Guittot , Tim Chen , Mel Gorman , Juri Lelli , Rik van Riel , Aaron Lu , Abel Wu , K Prateek Nayak , Yicong Yang , "Gautham R . Shenoy" , Ingo Molnar , Dietmar Eggemann , Steven Rostedt , Ben Segall , Daniel Bristot de Oliveira , Valentin Schneider , linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH] sched/fair: Choose the CPU where short task is running during wake up Message-ID: References: <20220915165407.1776363-1-yu.c.chen@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220915165407.1776363-1-yu.c.chen@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 16, 2022 at 12:54:07AM +0800, Chen Yu wrote: > And the rq lock bottleneck is composed of two paths(perf profile): > > (path1): > raw_spin_rq_lock_nested.constprop.0; > try_to_wake_up; > default_wake_function; > autoremove_wake_function; > __wake_up_common; > __wake_up_common_lock; > __wake_up_sync_key; > pipe_write; > new_sync_write; > vfs_write; > ksys_write; > __x64_sys_write; > do_syscall_64; > entry_SYSCALL_64_after_hwframe;write Can you please addr2line -i the raw_spin_rq_lock callsite so we know which is the one causing grief? Specifically; I'm worried about PSI, psi_ttwu_dequeue() can cause ttwu() to take _2_ rq->lock, which absolutely blows for this case.