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 CF234C433FE for ; Mon, 14 Mar 2022 10:55:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238736AbiCNK5A (ORCPT ); Mon, 14 Mar 2022 06:57:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33100 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238614AbiCNK4z (ORCPT ); Mon, 14 Mar 2022 06:56:55 -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 D02FD43EE9; Mon, 14 Mar 2022 03:55:45 -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=uaaiBGW4jge4EZ1U6h8ArDMiqt/yHKf7XttgFGtE2/M=; b=hoV+/hsARD+41GgJwPvHacyLqV bVpCtL4H1CPrNZz3bd6ZYDLBjpcZRM43Q+B26oUSATlXgsTklsu6EWEvcUs4KnboJ01k8Td2AwuGp CbBQdHbag1H3ZmCQV27TtnY0rfcwjSDD31TGYWtjZfCtW+JJ2NK0eoX/PmrNQTqhowHISFjSbgSPy MwLjHMQjlW+6HsCTpU3ldYWhlszVKCioOP3u4jag11rcMNVf8lIlp0b9yECC33BLaVdkQyy5JqgNc n3wcG3PczcL5tEtzf7ROiXQMROV1hpvJDPHCm7DHOgoMp8p+71zQD8zElL3ZSg8zZ6IJ28EWbztou assNBj4Q==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1nTiM7-000oKu-07; Mon, 14 Mar 2022 10:55:15 +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 66297300325; Mon, 14 Mar 2022 11:55:12 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 23FB9284B4209; Mon, 14 Mar 2022 11:55:12 +0100 (CET) Date: Mon, 14 Mar 2022 11:55:12 +0100 From: Peter Zijlstra To: Wen Yang Cc: Stephane Eranian , Wen Yang , Ingo Molnar , Arnaldo Carvalho de Melo , Alexander Shishkin , Thomas Gleixner , mark rutland , jiri olsa , namhyung kim , borislav petkov , x86@kernel.org, "h. peter anvin" , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RESEND PATCH 2/2] perf/x86: improve the event scheduling to avoid unnecessary pmu_stop/start Message-ID: References: <20220304110351.47731-1-simon.wy@alibaba-inc.com> <20220304110351.47731-2-simon.wy@alibaba-inc.com> <0c119da1-053b-a2d6-1579-8fb09dbe8e63@linux.alibaba.com> <271bc186-7ffb-33c8-4934-cda2beb94816@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <271bc186-7ffb-33c8-4934-cda2beb94816@linux.alibaba.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 10, 2022 at 11:50:33AM +0800, Wen Yang wrote: > As you pointed out, some non-compliant rdpmc can cause problems. But you > also know that linux is the foundation of cloud servers, and many > third-party programs run on it (we don't have any code for it), and we can > only observe that the monitoring data will jitter abnormally (the > probability of this issue is not high, about dozens of tens of thousands of > machines). This might be a novel insight, but I *really* don't give a crap about any of that. If they're not using it right, they get to keep the pieces. I'd almost make it reschedule more to force them to fix their stuff.