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 744B9C04FDF for ; Wed, 16 Aug 2023 12:38:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245282AbjHPMhj (ORCPT ); Wed, 16 Aug 2023 08:37:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42598 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244571AbjHPMh3 (ORCPT ); Wed, 16 Aug 2023 08:37:29 -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 69EF21FF9 for ; Wed, 16 Aug 2023 05:37:28 -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=meButugzK+c8b7F/2W247t2wjtoumPjf98JrcWTnXLk=; b=clHXquPzLZPNUfJ/MkxaqbYb3Y I2vcp4UlQJFz7KT+/RXOOlNFUMtMsUK6prRFwzZKkrTHa+lIasMeLbY0824nvgbF7e8LOn1gDRFGB hyU4qzRQpF2Tcxyml4YJOBtlQLIW7GpJ5dP55DkKjVrzt9Z5c5ANn7Ugp8ePPz/6kJMAeeQl98FQv deIeS42+iR/FLxgKMT5ILnoR+gfjqE81YZLe4q+nQJ8xW9FJHNp0RcW9dTFCv0MHvQsIL6obrDMDu iEcpsffCybCb0CfnY8DAGLUKuQoJluykptTZ+Wt62rIuyfWiULmEfFqh+BImwUhQK23YETX+V8679 MbJTmnWA==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1qWFm0-00CzLf-2c; Wed, 16 Aug 2023 12:37:17 +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 32ED13001FD; Wed, 16 Aug 2023 14:37:16 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 1AB6A2C2FDF3F; Wed, 16 Aug 2023 14:37:16 +0200 (CEST) Date: Wed, 16 Aug 2023 14:37:16 +0200 From: Peter Zijlstra To: Mike Galbraith Cc: Chen Yu , kernel test robot , oe-lkp@lists.linux.dev, lkp@intel.com, linux-kernel@vger.kernel.org, x86@kernel.org, Ingo Molnar Subject: Re: [tip:sched/eevdf] [sched/fair] e0c2ff903c: phoronix-test-suite.blogbench.Write.final_score -34.8% regression Message-ID: <20230816123716.GI980931@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 Mon, Aug 14, 2023 at 08:32:55PM +0200, Mike Galbraith wrote: > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -875,6 +875,12 @@ static struct sched_entity *pick_eevdf(s > if (curr && (!curr->on_rq || !entity_eligible(cfs_rq, curr))) > curr = NULL; > > + /* > + * Once selected, run the task to parity to avoid overscheduling. > + */ > + if (sched_feat(RUN_TO_PARITY) && curr) > + return curr; > + > while (node) { > struct sched_entity *se = __node_2_se(node); > So I read it wrong last night... but I rather like this idea. But there's something missing. When curr starts a new slice it should probably do a full repick and not stick with it. Let me poke at this a bit.. nice