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=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,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 9CA08C43441 for ; Wed, 21 Nov 2018 08:14:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6591721479 for ; Wed, 21 Nov 2018 08:14:35 +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="HcVN5T3l" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6591721479 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728562AbeKUSsF (ORCPT ); Wed, 21 Nov 2018 13:48:05 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:47622 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726195AbeKUSsE (ORCPT ); Wed, 21 Nov 2018 13:48:04 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.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=ZJewmOd27OA7wEvszIakppkkEWlgf5r/zdAFQHC65UE=; b=HcVN5T3lK/0weBYz8SOebscqe SCzBj+kzl+83p21XUVmAZGGU/ry60zIcXWmqfCbMXVz8oWtGD+fgq7SwgsjKDFc1X+XsLs84mx6vS TDaMJ5Q8KZkC7e5ZCn0NvXG1mCRfsi6/RmBNHSqBlDK7+pu+XMCqE1FMqAOJqmWk7TqVvqMny6vor dDEqU6+gqhGNeW68XPULAZonqVFJYbsFqsqfch8DRmJg9LBT0YOMz+CJNyI778oRKnIoFDK5LGEjd M44/n9JWh3M2R7rJVCtt5LvNRqCkfoNUI4az8OSn5xZQ02RXGas6dwtEgLs0ZzPfuCVE5GAIo2JVR 3/CMPV5EA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1gPNeR-0002rZ-6j; Wed, 21 Nov 2018 08:14:23 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 8CDC02029FD58; Wed, 21 Nov 2018 09:14:20 +0100 (CET) Date: Wed, 21 Nov 2018 09:14:20 +0100 From: Peter Zijlstra To: Andi Kleen Cc: Kyle Huey , Kan Liang , Ingo Molnar , Robert O'Callahan , Alexander Shishkin , Arnaldo Carvalho de Melo , Jiri Olsa , Linus Torvalds , Stephane Eranian , Thomas Gleixner , Vince Weaver , acme@kernel.org, open list Subject: Re: [REGRESSION] x86, perf: counter freezing breaks rr Message-ID: <20181121081420.GF2131@hirez.programming.kicks-ass.net> References: <20181120194129.GC13936@tassilo.jf.intel.com> <20181120201144.GD13936@tassilo.jf.intel.com> <20181120221642.GE2131@hirez.programming.kicks-ass.net> <20181120222549.GA2149@hirez.programming.kicks-ass.net> <20181120223854.GH13936@tassilo.jf.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181120223854.GH13936@tassilo.jf.intel.com> 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, Nov 20, 2018 at 02:38:54PM -0800, Andi Kleen wrote: > > In fact, I'll argue FREEZE_ON_OVERFLOW is unfixably broken for > > independent counters, because while one counter overflows, we'll stall > > counting on all others until we've handled the PMI. > > > > Even though the PMI might not be for them and they very much want/need > > to continue counting. > > We stop all counters in any case for the PMI. With freeze-on-PMI it just > happens slightly earlier. Hiding the PMI is fine and good. The PMI is not the workload. Stopping it earlier is _NOT_ good, it hides your actual workload.