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=-5.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, URIBL_BLOCKED,USER_AGENT_MUTT 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 5A6E4C43381 for ; Wed, 20 Mar 2019 12:25:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1BD422184D for ; Wed, 20 Mar 2019 12:25:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Dfru4UH0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727616AbfCTMZa (ORCPT ); Wed, 20 Mar 2019 08:25:30 -0400 Received: from merlin.infradead.org ([205.233.59.134]:50206 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726366AbfCTMZ3 (ORCPT ); Wed, 20 Mar 2019 08:25:29 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.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:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=smgpF9UKcmBfA9N5X/DOY2q9U2CSoD48XaQLEORD2dI=; b=Dfru4UH0ntTrplb6Ke5efLEJE rkznrgnYBSKt6cUgqtBbkSVef9olE7JcagcMs64PgwoMsT95Sq2cdBE/axhYpDQiEYbPKGeCuFNmY NXZwcLn1vLAzKhx3jV0vghnWzuK0JjsVWuHMiGAXxZiIKh06a9BjatNep27D8fjIWKXmlTv/9L/ny HYUJ4DrWW55x4O4A6Z40e0hOSDkUpPDpkIPAFAorWgRQJ+KH+fQQlBkwJXqaJ9NPabukcFeSs4M58 sCvSOT7kXAYLXQV89FKckicNVUg7xpI8m/TyLUYa/DN9ip2G5R2BkNxCe+ssHPcYecBYlyxDd0zFk Igw9mSZBA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1h6aHU-0002cC-GI; Wed, 20 Mar 2019 12:25:16 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id F3C5923EA30BA; Wed, 20 Mar 2019 13:25:14 +0100 (CET) Date: Wed, 20 Mar 2019 13:25:14 +0100 From: Peter Zijlstra To: Stephane Eranian Cc: Ingo Molnar , Jiri Olsa , LKML , tonyj@suse.com, nelson.dsouza@intel.com Subject: Re: [RFC][PATCH 6/8] perf/x86: Clear ->event_constraint[] on put Message-ID: <20190320122514.GF6058@hirez.programming.kicks-ass.net> References: <20190314130113.919278615@infradead.org> <20190314130705.956098225@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 19, 2019 at 02:50:21PM -0700, Stephane Eranian wrote: > On Thu, Mar 14, 2019 at 6:11 AM Peter Zijlstra wrote: > > > > The current code unconditionally clears cpuc->event_constraint[i] > > before calling get_event_constraints(.idx=i). The only site that cares > > is intel_get_event_constraints() where the c1 load will always be > > NULL. > > > > However, always calling get_event_constraints() on all events is > > wastefull, most times it will return the exact same result. Therefore > > retain the logic in intel_get_event_constraints() and change the > > generic code to only clear the constraint on put. > > > > Signed-off-by: Peter Zijlstra (Intel) > > I thought there was caching of the constraint in case it was static > (or unconstrained) Yeah, I was under the same impression :-/ > to avoid walking the constraint table each time between invocations > on the same group_sched_in() call. But the way the c1 vs. c2 logic > is written I don't see it. In which case, this could be another opportunity. Right, the next patch attempts this.