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 5D2F0C433EF for ; Mon, 13 Jun 2022 08:54:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240474AbiFMIyw (ORCPT ); Mon, 13 Jun 2022 04:54:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49440 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240479AbiFMIyn (ORCPT ); Mon, 13 Jun 2022 04:54:43 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 885B9B4AD for ; Mon, 13 Jun 2022 01:54:42 -0700 (PDT) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id 3E37821A6F; Mon, 13 Jun 2022 08:54:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1655110481; h=from:from:reply-to: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=x6EzP/SNl2aHgcErZAiM07TxOTw9Y5d8zGy4RjavR0s=; b=QMpch2e5jylY76PxB3EoaBBinXIXWjTjbQA7eu7c+05/pytcyOkm+9idUrvBHjG2gGWGex AEYcaV56kiG1Z6lrPu5y4pETQqS4h3LqYL4W2fr32AhfwRRXhQYk/L9YpOVN5noZcCd0hs pDqrImnEdUtcxC1TrOtisSCZFbRDIHc= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1655110481; h=from:from:reply-to: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=x6EzP/SNl2aHgcErZAiM07TxOTw9Y5d8zGy4RjavR0s=; b=1YuFBATmhJW1bK2y75DttzqhxcbQXkyi/VytJmVe5YitrqXYgkjI9EQ6IuoUqrRZ21MONL nDHAU3OtQNQdIVDg== Received: from suse.de (unknown [10.163.43.106]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 2CFF52C141; Mon, 13 Jun 2022 08:54:38 +0000 (UTC) Date: Mon, 13 Jun 2022 09:54:37 +0100 From: Mel Gorman To: Chen Yu Cc: Yicong Yang , Peter Zijlstra , Vincent Guittot , yangyicong@hisilicon.com, Ingo Molnar , Juri Lelli , Dietmar Eggemann , Steven Rostedt , Barry Song <21cnbao@gmail.com>, Srikar Dronamraju , Len Brown , Ben Segall , Aubrey Li , Abel Wu , Daniel Bristot de Oliveira , Tim Chen , linux-kernel@vger.kernel.org, K Prateek Nayak , Mohini Narkhede Subject: Re: [PATCH v4] sched/fair: Introduce SIS_UTIL to search idle CPU based on sum of util_avg Message-ID: <20220613085437.GC3195@suse.de> References: <20220612163428.849378-1-yu.c.chen@intel.com> <20220613080636.GA32587@chenyu5-mobl1> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20220613080636.GA32587@chenyu5-mobl1> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 13, 2022 at 04:06:36PM +0800, Chen Yu wrote: > On Mon, Jun 13, 2022 at 03:40:52PM +0800, Yicong Yang wrote: > > On 2022/6/13 0:34, Chen Yu wrote: > > > > [cut...] > > > #define NUMA_IMBALANCE_MIN 2 > > > diff --git a/kernel/sched/features.h b/kernel/sched/features.h > > > index 1cf435bbcd9c..3334a1b93fc6 100644 > > > --- a/kernel/sched/features.h > > > +++ b/kernel/sched/features.h > > > @@ -61,6 +61,7 @@ SCHED_FEAT(TTWU_QUEUE, true) > > > * When doing wakeups, attempt to limit superfluous scans of the LLC domain. > > > */ > > > SCHED_FEAT(SIS_PROP, true) > > > +SCHED_FEAT(SIS_UTIL, true) > > > > > > > confused here that shouldn't we have SCHED_FEAT(SIS_PROP, false)? With SIS_UTIL enabled, SIS_PROP will have no > > effect since nr is overridden by SIS_UTIL. > Yes, no matter what SIS_PROP is set, the result of SIS_UTIL would be used to decide > the scan depth. We don't change the default value of SIS_PROP here, as this patch > tends to only touch one feature at one time. And the options could be tuned by user via > sysfs manually. Besides, the target is to replace SIS_PROP with another search policy, > Peter mentioned that "And ideally we're remove SIS_PROP after a few releases if this > works out", so I assume that changing the default value of SIS_PROP does not matter > in current patch. > I had expected it to be disabled given that SIS_PROP does work to calculcate nr, then discards it, and uses SIS_UTIL. If SIS_UTIL shows a regression and reports a bug, the first step would be to disable SIS_UTIL and enable SIS_PROP via sched_feat. -- Mel Gorman SUSE Labs