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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 A465BC433B4 for ; Mon, 3 May 2021 09:25:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 60DE861244 for ; Mon, 3 May 2021 09:25:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233040AbhECJ0B (ORCPT ); Mon, 3 May 2021 05:26:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38538 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231531AbhECJZ7 (ORCPT ); Mon, 3 May 2021 05:25:59 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CDB0CC06174A for ; Mon, 3 May 2021 02:25:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; 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=s5o4vQEaLgwOoh1Fmib+Iw0/gAmMNldp6drCnbbZgvY=; b=Uu/ARTImKC4N7vnpFJa3kmMyPb /9cjibnjkckAJ52ZVzcCVri5qz3xM8ECZ5uQMQOqSxXu4vna7m0EyloQwnopMpNJD9K3MgdFMzMgm 4g+anLCjTe06hPV3b0OxGZ34pvRgDcjZdVvv3HklDs3shUYZ6DeyOpxm/Wdu1s9h93fawZvF9zk6R xE0sHetZJN8wgKDfAPeFkCoUxIDWSksplFya1pFOLkzUqwwmb8wu9ATf5NF2yuVgo2aOuYq5x7W2r MyAtykWX1/UgSbDDcceBpuAa1SEFbViRdFt5UqQXfpoggLIHOzgLkd4y+lDsUFCq7aKhLlaUGOAmg vz0LKY+Q==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94 #2 (Red Hat Linux)) id 1ldUoX-00DWs0-4T; Mon, 03 May 2021 09:24:30 +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 (2048 bits) server-digest SHA256) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id D0F5E3001D0; Mon, 3 May 2021 11:24:25 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id A24612BC22555; Mon, 3 May 2021 11:24:25 +0200 (CEST) Date: Mon, 3 May 2021 11:24:25 +0200 From: Peter Zijlstra To: Ricardo Neri Cc: Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Len Brown , Srinivas Pandruvada , Tim Chen , Aubrey Li , "Ravi V. Shankar" , Ricardo Neri , Quentin Perret , "Joel Fernandes (Google)" , linux-kernel@vger.kernel.org, Aubrey Li , Ben Segall , Daniel Bristot de Oliveira Subject: Re: [PATCH v2 1/4] sched/fair: Optimize checking for group_asym_packing Message-ID: References: <20210414020436.12980-1-ricardo.neri-calderon@linux.intel.com> <20210414020436.12980-2-ricardo.neri-calderon@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210414020436.12980-2-ricardo.neri-calderon@linux.intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 13, 2021 at 07:04:33PM -0700, Ricardo Neri wrote: > By checking local_group, we can avoid additional checks and invoking > sched_asmy_prefer() when it is not needed. This really could do with a few words on *why* that is correct. ISTR thinking this made sense when I last looked at it, but today, after having the brain reset by not looking at a computer for 4 days its not immediate obvious anymore. > Signed-off-by: Ricardo Neri > --- > kernel/sched/fair.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 04a3ce20da67..4ef3fa0d5e8d 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -8455,7 +8455,7 @@ static inline void update_sg_lb_stats(struct lb_env *env, > } > > /* Check if dst CPU is idle and preferred to this group */ > - if (env->sd->flags & SD_ASYM_PACKING && > + if (!local_group && env->sd->flags & SD_ASYM_PACKING && > env->idle != CPU_NOT_IDLE && > sgs->sum_h_nr_running && > sched_asym_prefer(env->dst_cpu, group->asym_prefer_cpu)) { > -- > 2.17.1 >