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=-11.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, 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 A1B44C4742C for ; Thu, 5 Nov 2020 14:48:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4024221734 for ; Thu, 5 Nov 2020 14:48:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730973AbgKEOr6 (ORCPT ); Thu, 5 Nov 2020 09:47:58 -0500 Received: from mga12.intel.com ([192.55.52.136]:35491 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727275AbgKEOr6 (ORCPT ); Thu, 5 Nov 2020 09:47:58 -0500 IronPort-SDR: eYjb6cwsr2CpGty/ip9Ffb3lonFJen/wo2mX06undcstA30oOfvMGt7+Hzw7eNOnhcA/OkbIuZ eFwGKvzL0ZIg== X-IronPort-AV: E=McAfee;i="6000,8403,9795"; a="148671571" X-IronPort-AV: E=Sophos;i="5.77,453,1596524400"; d="scan'208";a="148671571" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Nov 2020 06:47:57 -0800 IronPort-SDR: xc6lYkzB0wsZKzibQC+/AVpt8xmjyABKWw+VKmE3YyNZRkkMJHBlxgJLw50Tzwo1RIYScWcGdb bD3UecaE0l/w== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.77,453,1596524400"; d="scan'208";a="397270363" Received: from linux.intel.com ([10.54.29.200]) by orsmga001.jf.intel.com with ESMTP; 05 Nov 2020 06:47:56 -0800 Received: from [10.254.97.216] (kliang2-MOBL.ccr.corp.intel.com [10.254.97.216]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by linux.intel.com (Postfix) with ESMTPS id EA1F158073D; Thu, 5 Nov 2020 06:47:55 -0800 (PST) Subject: Re: [RFC 1/2] perf/core: Enable sched_task callbacks if PMU has it To: Namhyung Kim , Peter Zijlstra , Ingo Molnar Cc: Arnaldo Carvalho de Melo , Jiri Olsa , LKML , Stephane Eranian , Andi Kleen , Ian Rogers , Gabriel Marin References: <20201102145221.309001-1-namhyung@kernel.org> <20201102145221.309001-2-namhyung@kernel.org> From: "Liang, Kan" Message-ID: Date: Thu, 5 Nov 2020 09:47:54 -0500 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.12.1 MIME-Version: 1.0 In-Reply-To: <20201102145221.309001-2-namhyung@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/2/2020 9:52 AM, Namhyung Kim wrote: > If an event associated with a PMU which has a sched_task callback, > it should be called regardless of cpu/task context. For example, I don't think it's necessary. We should call it when we have to. Otherwise, it just waste cycles. Shouldn't the patch 2 be enough? Thanks, Kan > a per-cpu event might enable large PEBS buffers so it needs to flush > the buffer whenever task scheduling happens. > > The underlying PMU may or may not require this for the given event, > but it will be handled in the pmu::sched_task() callback anyway. > > Signed-off-by: Namhyung Kim > --- > kernel/events/core.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/kernel/events/core.c b/kernel/events/core.c > index b458ed3dc81b..aaa0155c4142 100644 > --- a/kernel/events/core.c > +++ b/kernel/events/core.c > @@ -4696,6 +4696,8 @@ static void unaccount_event(struct perf_event *event) > dec = true; > if (has_branch_stack(event)) > dec = true; > + if (event->pmu->sched_task) > + dec = true; > if (event->attr.ksymbol) > atomic_dec(&nr_ksymbol_events); > if (event->attr.bpf_event) > @@ -11225,6 +11227,8 @@ static void account_event(struct perf_event *event) > inc = true; > if (is_cgroup_event(event)) > inc = true; > + if (event->pmu->sched_task) > + inc = true; > if (event->attr.ksymbol) > atomic_inc(&nr_ksymbol_events); > if (event->attr.bpf_event) >