From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-5.9 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI,UNPARSEABLE_RELAY autolearn=unavailable autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id 644317D08A for ; Thu, 9 May 2019 10:31:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726192AbfEIKbv (ORCPT ); Thu, 9 May 2019 06:31:51 -0400 Received: from mailgw02.mediatek.com ([210.61.82.184]:33223 "EHLO mailgw02.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1725892AbfEIKbu (ORCPT ); Thu, 9 May 2019 06:31:50 -0400 X-UUID: 49b54b4d4c1e425091c7a2b3e6c30802-20190509 X-UUID: 49b54b4d4c1e425091c7a2b3e6c30802-20190509 Received: from mtkcas07.mediatek.inc [(172.21.101.84)] by mailgw02.mediatek.com (envelope-from ) (mhqrelay.mediatek.com ESMTP with TLS) with ESMTP id 1425517763; Thu, 09 May 2019 18:31:39 +0800 Received: from mtkcas08.mediatek.inc (172.21.101.126) by mtkmbs01n1.mediatek.inc (172.21.101.68) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Thu, 9 May 2019 18:31:38 +0800 Received: from mtksdccf07.mediatek.inc (172.21.84.99) by mtkcas08.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1395.4 via Frontend Transport; Thu, 9 May 2019 18:31:38 +0800 From: To: , CC: , , , , Lecopzer Chen Subject: [PATCH] Documentation: {u,k}probes: add tracing_on before tracing Date: Thu, 9 May 2019 18:31:16 +0800 Message-ID: <1557397876-18153-1-git-send-email-lecopzer.chen@mediatek.com> X-Mailer: git-send-email 1.9.1 MIME-Version: 1.0 Content-Type: text/plain X-MTK: N Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org From: Lecopzer Chen After following the document step by step, the `cat trace` can't be worked without enabling tracing_on and might mislead newbies about the functionality. Signed-off-by: Lecopzer Chen --- Documentation/trace/kprobetrace.rst | 6 ++++++ Documentation/trace/uprobetracer.rst | 7 ++++++- 2 files changed, 12 insertions(+), 1 deletion(-) diff --git a/Documentation/trace/kprobetrace.rst b/Documentation/trace/kprobetrace.rst index 235ce2ab131a..baa3c42ba2f4 100644 --- a/Documentation/trace/kprobetrace.rst +++ b/Documentation/trace/kprobetrace.rst @@ -189,6 +189,12 @@ events, you need to enable it. echo 1 > /sys/kernel/debug/tracing/events/kprobes/myprobe/enable echo 1 > /sys/kernel/debug/tracing/events/kprobes/myretprobe/enable +Use the following command to start tracing in an interval. +:: + # echo 1 > tracing_on + Open something... + # echo 0 > tracing_on + And you can see the traced information via /sys/kernel/debug/tracing/trace. :: diff --git a/Documentation/trace/uprobetracer.rst b/Documentation/trace/uprobetracer.rst index 4346e23e3ae7..0b21305fabdc 100644 --- a/Documentation/trace/uprobetracer.rst +++ b/Documentation/trace/uprobetracer.rst @@ -152,10 +152,15 @@ events, you need to enable it by:: # echo 1 > events/uprobes/enable -Lets disable the event after sleeping for some time. +Lets start tracing, sleep for some time and stop tracing. :: + # echo 1 > tracing_on # sleep 20 + # echo 0 > tracing_on + +Also, you can disable the event by:: + # echo 0 > events/uprobes/enable And you can see the traced information via /sys/kernel/debug/tracing/trace. -- 2.18.0