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,URIBL_BLOCKED, 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 03CABC43381 for ; Thu, 21 Mar 2019 21:21:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C439D21917 for ; Thu, 21 Mar 2019 21:21:07 +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="akWTgSgs" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727174AbfCUVVG (ORCPT ); Thu, 21 Mar 2019 17:21:06 -0400 Received: from merlin.infradead.org ([205.233.59.134]:39802 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726230AbfCUVVF (ORCPT ); Thu, 21 Mar 2019 17:21:05 -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=op9LrgN0NfpX9qaWbUMS7GOpU+ohtf+wMzZbm+v0L2s=; b=akWTgSgsY8x17OObaboYJ3fBE K6ciDuYZuX2hyMS1iBU+zqZ5IjKfrlutJDgEWC6ffuOF/cQWlzMKoXxlpmuEzqTf0kZHTCKo8oojq kqOlgQk/nDmAwBh5k6VsJQod/Tmk6lxUC3FOJBPhG2mrs3vkBpqEJXem1lbeNfGgBXb1b0rD6Y7n1 di/Kui3Woi+a37HqrjgcaGGBTeL+E7dO0s6yxhSs61TBK06UUVrZLYYr23bIMgoa7XhU013x174dN S54ASR4kqrUmguVcdkSRt5ulFPiOpJJ4hXHZju1DpFjA9+Ng6G6PFx1q5AaOjayqStF1DQwtfaWZp 4sghAT46Q==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=worktop.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1h757V-0002hC-HA; Thu, 21 Mar 2019 21:21:01 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id 6C7C5984EEA; Thu, 21 Mar 2019 22:20:59 +0100 (CET) Date: Thu, 21 Mar 2019 22:20:59 +0100 From: Peter Zijlstra To: kan.liang@linux.intel.com 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: <20190321212059.GD7905@worktop.programming.kicks-ass.net> References: <20190321205703.4256-1-kan.liang@linux.intel.com> <20190321205703.4256-5-kan.liang@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190321205703.4256-5-kan.liang@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 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()? > + > + 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); > }