From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756692AbcAYKLS (ORCPT ); Mon, 25 Jan 2016 05:11:18 -0500 Received: from szxga01-in.huawei.com ([58.251.152.64]:38438 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756021AbcAYJ63 (ORCPT ); Mon, 25 Jan 2016 04:58:29 -0500 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 47/54] perf tools: Detect avalibility of write_backward Date: Mon, 25 Jan 2016 09:56:34 +0000 Message-ID: <1453715801-7732-48-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 Content-Type: text/plain X-Originating-IP: [10.107.193.248] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020203.56A5F1A6.00F1,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: 75dfe59f3ffcd5b0054c23caa553dfad Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Detect avalibility of write_backward and save the result into record_opts. With write_backward the start pointer of a ring buffer mapped read only can be found reliably. Signed-off-by: Wang Nan Signed-off-by: He Kuang Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Zefan Li Cc: pi3orama@163.com --- tools/perf/perf.h | 1 + tools/perf/util/record.c | 11 +++++++++++ 2 files changed, 12 insertions(+) diff --git a/tools/perf/perf.h b/tools/perf/perf.h index 90129ac..00c25b1 100644 --- a/tools/perf/perf.h +++ b/tools/perf/perf.h @@ -71,6 +71,7 @@ struct record_opts { bool sample_transaction; unsigned initial_delay; bool use_clockid; + bool has_write_backward; clockid_t clockid; unsigned int proc_map_timeout; }; diff --git a/tools/perf/util/record.c b/tools/perf/util/record.c index 0467367..d01f155 100644 --- a/tools/perf/util/record.c +++ b/tools/perf/util/record.c @@ -85,6 +85,11 @@ static void perf_probe_comm_exec(struct perf_evsel *evsel) evsel->attr.comm_exec = 1; } +static void perf_probe_write_backward(struct perf_evsel *evsel) +{ + evsel->attr.write_backward = 1; +} + static void perf_probe_context_switch(struct perf_evsel *evsel) { evsel->attr.context_switch = 1; @@ -105,6 +110,11 @@ bool perf_can_record_switch_events(void) return perf_probe_api(perf_probe_context_switch); } +static bool perf_can_write_backward(void) +{ + return perf_probe_api(perf_probe_write_backward); +} + bool perf_can_record_cpu_wide(void) { struct perf_event_attr attr = { @@ -235,6 +245,7 @@ static int record_opts__config_freq(struct record_opts *opts) int record_opts__config(struct record_opts *opts) { + opts->has_write_backward = perf_can_write_backward(); return record_opts__config_freq(opts); } -- 1.8.3.4