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 6C885C3A5A2 for ; Fri, 23 Aug 2019 13:03:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3FF1E22CE3 for ; Fri, 23 Aug 2019 13:03:42 +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="L6eKFF9y" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404285AbfHWNDl (ORCPT ); Fri, 23 Aug 2019 09:03:41 -0400 Received: from merlin.infradead.org ([205.233.59.134]:38238 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404041AbfHWNDk (ORCPT ); Fri, 23 Aug 2019 09:03:40 -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=d/8OC8qK7AH729RYuk/u+nW1ro0Plfkg+QQGzVTANr8=; b=L6eKFF9ypk0LmLF7nc13NiAyN mVRGyMd+ZBjHbHJ4c7M9bpNUm5oNB/WN4clmoDYOV5w9NxfGmHN4Oc9nJLnKrqA2IqJupzfpaUCih i6TM+ZI/b+3wKv8eGVaiGjoPNwpEJgeRxtsn2oRbCYrEjl177tgUquVVTTGwqCxaa+Mk8vtpxAe+i LgpsrSIZ2p0NgK8v40CccfhA0F52zEj6Z7Dt5hUDQqZIxwzsfTVoThPb9CniCM6fo9hW1iFiqGELu lLMCC1/KQJDmngOsHyqlvYmu4JexwiqDedr62bPBsRiDVcIWHl+0Q3HzBGF7vxSKwi77m7yMieOpv GzIX+B6NA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1i19Dy-0001bh-5e; Fri, 23 Aug 2019 13:03:26 +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 A027D307510; Fri, 23 Aug 2019 15:02:50 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 11044202245C4; Fri, 23 Aug 2019 15:03:23 +0200 (CEST) Date: Fri, 23 Aug 2019 15:03:23 +0200 From: Peter Zijlstra To: Ganapatrao Kulkarni Cc: Ian Rogers , Ingo Molnar , Arnaldo Carvalho de Melo , Alexander Shishkin , Jiri Olsa , Namhyung Kim , LKML , Kan Liang , Andi Kleen , Stephane Eranian , Ganapatrao Kulkarni , Jayachandran Chandrasekharan Nair Subject: Re: [PATCH] perf cgroups: Don't rotate events for cgroups unnecessarily Message-ID: <20190823130322.GO2349@hirez.programming.kicks-ass.net> References: <20190601082722.44543-1-irogers@google.com> <20190621082422.GH3436@hirez.programming.kicks-ass.net> <20190624075520.GC3436@hirez.programming.kicks-ass.net> <20190823115946.GM2349@hirez.programming.kicks-ass.net> 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 Fri, Aug 23, 2019 at 06:26:34PM +0530, Ganapatrao Kulkarni wrote: > On Fri, Aug 23, 2019 at 5:29 PM Peter Zijlstra wrote: > > On Fri, Aug 23, 2019 at 04:13:46PM +0530, Ganapatrao Kulkarni wrote: > > > > > We are seeing regression with our uncore perf driver(Marvell's > > > ThunderX2, ARM64 server platform) on 5.3-Rc1. > > > After bisecting, it turned out to be this patch causing the issue. > > > > Funnily enough; the email you replied to didn't contain a patch. > > Hmm sorry, not sure why the patch is clipped-off, I see it in my inbox. Your email is in a random spot of the discussion for me. At least it was fairly easy to find the related patch. > > > Test case: > > > Load module and run perf for more than 4 events( we have 4 counters, > > > event multiplexing takes place for more than 4 events), then unload > > > module. > > > With this sequence of testing, the system hangs(soft lockup) after 2 > > > or 3 iterations. Same test runs for hours on 5.2. > > > > > > while [ 1 ] > > > do > > > rmmod thunderx2_pmu > > > modprobe thunderx2_pmu > > > perf stat -a -e \ > > > uncore_dmc_0/cnt_cycles/,\ > > > uncore_dmc_0/data_transfers/,\ > > > uncore_dmc_0/read_txns/,\ > > > uncore_dmc_0/config=0xE/,\ > > > uncore_dmc_0/write_txns/ sleep 1 > > > sleep 2 > > > done > > > > Can you reproduce without the module load+unload? I don't think people > > routinely unload modules. > > The issue wont happen, if module is not unloaded/reloaded. > IMHO, this could be potential bug! Does the softlockup give a useful stacktrace? I don't have a thunderx2 so I cannot reproduce.