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=-10.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, 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 6D5A1C71155 for ; Tue, 1 Dec 2020 11:04:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EA73C206CB for ; Tue, 1 Dec 2020 11:04:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="TyNJoR+b" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388414AbgLALD4 (ORCPT ); Tue, 1 Dec 2020 06:03:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41608 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729425AbgLALDz (ORCPT ); Tue, 1 Dec 2020 06:03:55 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 928E6C0613CF for ; Tue, 1 Dec 2020 03:03:15 -0800 (PST) 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=R7lTicv2X0dQEiz5cgZYJHulalzBL3nNEkOe9sOfN8U=; b=TyNJoR+bUpbzExNeyK5XVj93s5 jERnsJPobqpdDOBZ53O3rKEpGm8EjqPpKipKMdFgaKBQAjEoaQkBBO76fPM+x6uyZPpQ2//hRBk2G LVUkC+1LbEb66x1VkAYXgA7ECAfbWuIF8mmZmSWJy1IzC5Pf/xq3kip6PfCRaFKLyYgaBWfRivG5w Of59+GL7zkTwwVpjBwdx+Jhi7wR07rsy+m6AdQSYUZjb1vY/BIiTRfaql7ZYkPCPJy0OnlxwILpVc ULSfpPfaMv+ZPEbPJU2tS2EKBSe2j3oblCmJpwIOzzkAKtfJnQN8Hk8DGDwQ0UFZK0CW52DRf7bdC Q9edWA8Q==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kk3Qz-0007Fe-6D; Tue, 01 Dec 2020 11:03:01 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 63B173059DD; Tue, 1 Dec 2020 12:03:00 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 4E7502BE3BFEB; Tue, 1 Dec 2020 12:03:00 +0100 (CET) Date: Tue, 1 Dec 2020 12:03:00 +0100 From: Peter Zijlstra To: Vincent Guittot Cc: Mel Gorman , Ingo Molnar , "Li, Aubrey" , Valentin Schneider , linux-kernel Subject: Re: [PATCH] sched/fair: Clear SMT siblings after determining the core is not idle Message-ID: <20201201110300.GR3040@hirez.programming.kicks-ass.net> References: <20201130144020.GS3371@techsingularity.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 Mon, Nov 30, 2020 at 03:47:01PM +0100, Vincent Guittot wrote: > On Mon, 30 Nov 2020 at 15:40, Mel Gorman wrote: > > > > The clearing of SMT siblings from the SIS mask before checking for an idle > > core is a small but unnecessary cost. Defer the clearing of the siblings > > until the scan moves to the next potential target. The cost of this was > > not measured as it is borderline noise but it should be self-evident. > > Good point > > > > > Signed-off-by: Mel Gorman > > Reviewed-by: Vincent Guittot Thanks!