From patchwork Tue Jan 19 11:16:46 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wang Nan X-Patchwork-Id: 59983 Delivered-To: patch@linaro.org Received: by 10.112.130.2 with SMTP id oa2csp2509342lbb; Tue, 19 Jan 2016 03:18:59 -0800 (PST) X-Received: by 10.98.71.73 with SMTP id u70mr43226534pfa.130.1453202339067; Tue, 19 Jan 2016 03:18:59 -0800 (PST) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id p13si47046536pfi.234.2016.01.19.03.18.58; Tue, 19 Jan 2016 03:18:59 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753416AbcASLSx (ORCPT + 29 others); Tue, 19 Jan 2016 06:18:53 -0500 Received: from szxga02-in.huawei.com ([119.145.14.65]:26636 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752264AbcASLST (ORCPT ); Tue, 19 Jan 2016 06:18:19 -0500 Received: from 172.24.1.47 (EHLO szxeml427-hub.china.huawei.com) ([172.24.1.47]) by szxrg02-dlp.huawei.com (MOS 4.3.7-GA FastPath queued) with ESMTP id DAE16860; Tue, 19 Jan 2016 19:17:08 +0800 (CST) Received: from linux-4hy3.site (10.107.193.248) by szxeml427-hub.china.huawei.com (10.82.67.182) with Microsoft SMTP Server id 14.3.235.1; Tue, 19 Jan 2016 19:17:00 +0800 From: Wang Nan To: , CC: , Wang Nan , He Kuang , Arnaldo Carvalho de Melo , "Brendan Gregg" , Jiri Olsa , "Masami Hiramatsu" , Namhyung Kim , Zefan Li , Subject: [PATCH 2/6] perf core: Set event's default overflow_handler Date: Tue, 19 Jan 2016 11:16:46 +0000 Message-ID: <1453202210-134429-3-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.3.4 In-Reply-To: <1453202210-134429-1-git-send-email-wangnan0@huawei.com> References: <20160118120230.GP6357@twins.programming.kicks-ass.net> <1453202210-134429-1-git-send-email-wangnan0@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.107.193.248] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020203.569E1B37.00A2, ss=1, re=0.000, recu=0.000, reip=0.000, cl=1, cld=1, fgs=0, ip=0.0.0.0, so=2013-06-18 04:22:30, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: f1a48de40ddcb25313946a54ad0992c2 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Set a default event->overflow_handler in perf_event_alloc() so don't need checking event->overflow_handler in __perf_event_overflow(). Following commits can give a different default overflow_handler. No extra performance introduced into hot path because in the original code we still need reading this handler from memory. A conditional branch is avoided so actually we remove some instructions. Initial idea comes from Peter at [1]. [1] http://lkml.kernel.org/r/20130708121557.GA17211@twins.programming.kicks-ass.net Signed-off-by: Wang Nan Cc: He Kuang Cc: Alexei Starovoitov Cc: Arnaldo Carvalho de Melo Cc: Brendan Gregg Cc: Jiri Olsa Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Zefan Li Cc: pi3orama@163.com --- kernel/events/core.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) -- 1.8.3.4 diff --git a/kernel/events/core.c b/kernel/events/core.c index 9e9c84da..f79c4be 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6402,10 +6402,7 @@ static int __perf_event_overflow(struct perf_event *event, irq_work_queue(&event->pending); } - if (event->overflow_handler) - event->overflow_handler(event, data, regs); - else - perf_event_output(event, data, regs); + event->overflow_handler(event, data, regs); if (*perf_event_fasync(event) && event->pending_kill) { event->pending_wakeup = 1; @@ -7874,8 +7871,13 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, context = parent_event->overflow_handler_context; } - event->overflow_handler = overflow_handler; - event->overflow_handler_context = context; + if (overflow_handler) { + event->overflow_handler = overflow_handler; + event->overflow_handler_context = context; + } else { + event->overflow_handler = perf_event_output; + event->overflow_handler_context = NULL; + } perf_event__state_init(event);