From patchwork Mon Jan 25 09:56:06 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wang Nan X-Patchwork-Id: 60287 Delivered-To: patch@linaro.org Received: by 10.112.130.2 with SMTP id oa2csp1254436lbb; Mon, 25 Jan 2016 01:59:19 -0800 (PST) X-Received: by 10.66.252.42 with SMTP id zp10mr24543258pac.29.1453715958919; Mon, 25 Jan 2016 01:59:18 -0800 (PST) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id 7si32678622pfk.172.2016.01.25.01.59.18; Mon, 25 Jan 2016 01:59:18 -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 S1756663AbcAYJ67 (ORCPT + 30 others); Mon, 25 Jan 2016 04:58:59 -0500 Received: from szxga02-in.huawei.com ([119.145.14.65]:23656 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756584AbcAYJ6p (ORCPT ); Mon, 25 Jan 2016 04:58:45 -0500 Received: from 172.24.1.51 (EHLO szxeml428-hub.china.huawei.com) ([172.24.1.51]) by szxrg02-dlp.huawei.com (MOS 4.3.7-GA FastPath queued) with ESMTP id DAM48124; Mon, 25 Jan 2016 17:57:27 +0800 (CST) Received: from linux-4hy3.site (10.107.193.248) by szxeml428-hub.china.huawei.com (10.82.67.183) with Microsoft SMTP Server id 14.3.235.1; Mon, 25 Jan 2016 17:57:17 +0800 From: Wang Nan To: Alexei Starovoitov , Arnaldo Carvalho de Melo CC: Brendan Gregg , Daniel Borkmann , "David S. Miller" , He Kuang , Jiri Olsa , Li Zefan , Masami Hiramatsu , Namhyung Kim , Peter Zijlstra , , Will Deacon , , Wang Nan Subject: [PATCH 19/54] perf core: Set event's default overflow_handler Date: Mon, 25 Jan 2016 09:56:06 +0000 Message-ID: <1453715801-7732-20-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.3.4 In-Reply-To: <1453715801-7732-1-git-send-email-wangnan0@huawei.com> References: <1453715801-7732-1-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=0001.0A020206.56A5F18A.00B3, 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: 155f9d7f27ef12883eb2ea55780d9e9c 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);