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=-5.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 24F22C3A5A2 for ; Fri, 23 Aug 2019 08:07:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DB44922CEC for ; Fri, 23 Aug 2019 08:07:19 +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="v/ir+K7N" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389103AbfHWIHS (ORCPT ); Fri, 23 Aug 2019 04:07:18 -0400 Received: from merlin.infradead.org ([205.233.59.134]:35838 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731543AbfHWIHS (ORCPT ); Fri, 23 Aug 2019 04:07:18 -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=HklP2O9Kga3Zf1O48/hnO6Dj5tVsMpIzpCAbR7UGcaQ=; b=v/ir+K7NcWiBEHyoGh8LziBYc X+sWsZZQw1eeD3ALOG3fb6oBMBxIP/KgL8f4beyO24Il9nsIl7tWESo/xHaPYF8kfvFAlGrF4V2E7 cc6TJ/e/3EZwlP05Rrph10QHTihJiL2/M+ybiXR0FAbYNqsuM/p21IWG4Byx1Kq3EdeZCh+KEDlx2 g7Z+iSP9YLFa7XurKqSs2lvwk/o7mKnaCvA2yyP1ECYnx1DXJWBGOkagL4hplGTYhJEt+1rB90Efg wyhAl/WSdqCQGSgV+u2fXmBRcz3Lyt7S9YaaRQsuKYhv/EDCybtSlk4jCrybQg/82o8a3bRXYHYQt PZOq21Yzw==; 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 1i14bE-00074E-KO; Fri, 23 Aug 2019 08:07:08 +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 896F7307145; Fri, 23 Aug 2019 10:06:34 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id BAD83202D580B; Fri, 23 Aug 2019 10:07:06 +0200 (CEST) Date: Fri, 23 Aug 2019 10:07:06 +0200 From: Peter Zijlstra To: Josh Hunt Cc: linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, acme@kernel.org, alexander.shishkin@linux.intel.com, jolsa@redhat.com, namhyung@kernel.org, bpuranda@akamai.com Subject: Re: [PATCH] perf/x86/intel: restrict period on Nehalem Message-ID: <20190823080706.GA2369@hirez.programming.kicks-ass.net> References: <1566256411-18820-1-git-send-email-johunt@akamai.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1566256411-18820-1-git-send-email-johunt@akamai.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 Mon, Aug 19, 2019 at 07:13:31PM -0400, Josh Hunt wrote: > We see our Nehalem machines reporting 'perfevents: irq loop stuck!' in > some cases when using perf: > > perfevents: irq loop stuck! > I found that a period limit of 32 was the lowest I could set it to without > the problem reoccurring. The idea for the patch and approach to find the > target value were suggested by Ingo and Thomas. > > Signed-off-by: Josh Hunt > Reported-by: Bhupesh Purandare > Suggested-by: Thomas Gleixner > Suggested-by: Ingo Molnar > Link: https://lore.kernel.org/lkml/20150501070226.GB18957@gmail.com/ > Link: https://lore.kernel.org/lkml/alpine.DEB.2.21.1908122133310.7324@nanos.tec.linutronix.de/ Thanks!