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 66F90C43381 for ; Fri, 22 Mar 2019 12:30:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 33C672054F for ; Fri, 22 Mar 2019 12:30:37 +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="DjBgkn7w" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390637AbfCVMaf (ORCPT ); Fri, 22 Mar 2019 08:30:35 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:58990 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389779AbfCVMad (ORCPT ); Fri, 22 Mar 2019 08:30:33 -0400 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=tbqj9yH3c6i2fdwjk5RqNfWptdmwcaU7Mv4hDOSCRGw=; b=DjBgkn7wR87i9b6rv3PofseYV AyEcNApeJV+JS/HKPcDEVS4iKFLtt16IoqS1F3AwMZIUpp07uCNtS3yYt47KyQ+K8OU4mTCkeC3jp UsL/iFYwIaFzjTnhJ+2eTDdMAUeKviGGnf5G+jFt9R97fqxxp2GZEi2+z/MNDh7DQLQBgGcshG+qz 0KfX6zt1snGzrml0rGkEVelpBaPa8drpiu1WPfMJYyZEtNU1uol87qFpIR2iZg7aGBw5LthQmkdRJ /yYFQ83iNnzwZ7/O/NKcoeltTC/mu373wGYgvNemo5Vwc6r6VAxW/pr83zilqU78Z8pCQuTUEZMHY 0mCqfaWHA==; 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 1h7JJc-0000VB-8X; Fri, 22 Mar 2019 12:30:28 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 8A4CE203C06F3; Fri, 22 Mar 2019 13:30:25 +0100 (CET) Date: Fri, 22 Mar 2019 13:30:25 +0100 From: Peter Zijlstra To: "Liang, Kan" Cc: acme@kernel.org, mingo@redhat.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, jolsa@kernel.org, eranian@google.com, alexander.shishkin@linux.intel.com, ak@linux.intel.com Subject: Re: [PATCH V2 04/23] perf/x86/intel: Support adaptive PEBSv4 Message-ID: <20190322123025.GS6058@hirez.programming.kicks-ass.net> References: <20190321205703.4256-1-kan.liang@linux.intel.com> <20190321205703.4256-5-kan.liang@linux.intel.com> <20190321212059.GD7905@worktop.programming.kicks-ass.net> <701a0cb7-d2ae-2d55-b5ef-57f4094c994f@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <701a0cb7-d2ae-2d55-b5ef-57f4094c994f@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, Mar 21, 2019 at 08:40:03PM -0400, Liang, Kan wrote: > > > On 3/21/2019 5:20 PM, Peter Zijlstra wrote: > > On Thu, Mar 21, 2019 at 01:56:44PM -0700, kan.liang@linux.intel.com wrote: > > > @@ -933,6 +1001,34 @@ pebs_update_state(bool needed_cb, struct cpu_hw_events *cpuc, struct pmu *pmu) > > > update = true; > > > } > > > + /* > > > + * The PEBS record doesn't shrink on the del. Because to get > > > + * an accurate config needs to go through all the existing pebs events. > > > + * It's not necessary. > > > + * There is no harmful for a bigger PEBS record, except little > > > + * performance impacts. > > > + * Also, for most cases, the same pebs config is applied for all > > > + * pebs events. > > > + */ > > > + if (x86_pmu.intel_cap.pebs_baseline && add) { > > > + u64 pebs_data_cfg; > > > + > > > + /* Clear pebs_data_cfg and pebs_record_size for first PEBS. */ > > > + if (cpuc->n_pebs == 1) { > > > + cpuc->pebs_data_cfg = 0; > > > + cpuc->pebs_record_size = sizeof(struct pebs_basic); > > > + } > > > > Argh, no. This is daft. The previous site was fine, it was just the > > pebs_record_size assignment I'm confused about. > > > > Note how by setting ->pebs_data_cfs to 0, you force the below branch to > > true and call adaptive_pebs_record_size_update() ? So _why_ do you have > > to set pebs_record_size()? > > > > I think we have to reset both cpuc->pebs_data_cfg and > cpuc->pebs_record_size. Because pebs_update_adaptive_cfg() can return 0. > If so, adaptive_pebs_record_size_update() will not be called. The > cpuc->pebs_record_size still use the stale data, which may be wrong. Oh, bugger.. I see. > > > + > > > + pebs_data_cfg = pebs_update_adaptive_cfg(event); > > > + > > > + /* Update pebs_record_size if new event requires more data. */ > > > + if (pebs_data_cfg & ~cpuc->pebs_data_cfg) { > > > + cpuc->pebs_data_cfg |= pebs_data_cfg; > > > + adaptive_pebs_record_size_update(); > > > + update = true; > > > + } > > > + } > > > + > > > if (update) > > > pebs_update_threshold(cpuc); > > > }