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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 5E31FC43141 for ; Thu, 14 Nov 2019 13:57:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 353B1206F4 for ; Thu, 14 Nov 2019 13:57:40 +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="kHR9fqvV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727053AbfKNN5j (ORCPT ); Thu, 14 Nov 2019 08:57:39 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:52004 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726254AbfKNN5i (ORCPT ); Thu, 14 Nov 2019 08:57:38 -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=lDnN/9X9Cy3nGKIfPbPORD6eLqZBeoY8DYM75RP+PVA=; b=kHR9fqvVMMIwGa9wpqf7cu3Q9 7kstGQluaRrCyA9Nk0Rs+bxKnYA6OOxUrQU39domY8IwIZHeq6E/guxbO2tPG3GFbx77kEjl7Cj2x FdjPWQZF3sifgHo71u7s+tXjENYmETxBFm3KcTssuiJFHZIZlsleVBc66SOkPiH7jKd9FYeapv/4p Joir6dQNRlvri62gmaMEvPIdHJVX97mZcEFbD1Umc9P1qTeiGGGc1e6JylZXmNxqx8w+oEo5F0/XL ybmYoCqypXb1xT0+Q3ArYgPGEzgKsqwJcwkPJpC5QcPacaJdNS4SfznyyaDqKk2Wod4QZ4y4WknBD MPt+p1UgQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1iVFce-00062A-W8; Thu, 14 Nov 2019 13:57:21 +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 E37A6304637; Thu, 14 Nov 2019 14:56:10 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 63585203A589D; Thu, 14 Nov 2019 14:57:18 +0100 (CET) Date: Thu, 14 Nov 2019 14:57:18 +0100 From: Peter Zijlstra To: "Liang, Kan" Cc: Ian Rogers , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Andrew Morton , Masahiro Yamada , Kees Cook , Catalin Marinas , Petr Mladek , Mauro Carvalho Chehab , Qian Cai , Joe Lawrence , Tetsuo Handa , Sri Krishna chowdary , "Uladzislau Rezki (Sony)" , Andy Shevchenko , Changbin Du , Ard Biesheuvel , "David S. Miller" , Kent Overstreet , Gary Hook , Arnd Bergmann , linux-kernel@vger.kernel.org, Stephane Eranian , Andi Kleen Subject: Re: [PATCH v3 10/10] perf/cgroup: Do not switch system-wide events in cgroup switch Message-ID: <20191114135718.GX4131@hirez.programming.kicks-ass.net> References: <20191114003042.85252-1-irogers@google.com> <20191114003042.85252-11-irogers@google.com> <20191114104340.GT4131@hirez.programming.kicks-ass.net> <710edaf6-2562-0f53-15d6-dc50885b8e08@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <710edaf6-2562-0f53-15d6-dc50885b8e08@linux.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 Thu, Nov 14, 2019 at 08:46:51AM -0500, Liang, Kan wrote: > > > On 11/14/2019 5:43 AM, Peter Zijlstra wrote: > > On Wed, Nov 13, 2019 at 04:30:42PM -0800, Ian Rogers wrote: > > > From: Kan Liang > > > > > > When counting system-wide events and cgroup events simultaneously, the > > > system-wide events are always scheduled out then back in during cgroup > > > switches, bringing extra overhead and possibly missing events. Switching > > > out system wide flexible events may be necessary if the scheduled in > > > task's cgroups have pinned events that need to be scheduled in at a higher > > > priority than the system wide flexible events. > > > > I'm thinking this patch is actively broken. groups->index 'group' wide > > and therefore across cpu/cgroup boundaries. > > > > There is no !cgroup to cgroup hierarchy as this patch seems to assume, > > specifically look at how the merge sort in visit_groups_merge() allows > > cgroup events to be picked before !cgroup events. > > > No, the patch intends to avoid switch !cgroup during cgroup context switch. Which is wrong.