From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-5.8 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham autolearn_force=no version=3.4.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id 612B47E892 for ; Fri, 13 Apr 2018 09:26:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754105AbeDMJ0c (ORCPT ); Fri, 13 Apr 2018 05:26:32 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:39866 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754097AbeDMJ0c (ORCPT ); Fri, 13 Apr 2018 05:26:32 -0400 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w3D9OVRu091463 for ; Fri, 13 Apr 2018 05:26:31 -0400 Received: from e06smtp10.uk.ibm.com (e06smtp10.uk.ibm.com [195.75.94.106]) by mx0a-001b2d01.pphosted.com with ESMTP id 2hast8ga3r-1 (version=TLSv1.2 cipher=AES256-SHA256 bits=256 verify=NOT) for ; Fri, 13 Apr 2018 05:26:31 -0400 Received: from localhost by e06smtp10.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Fri, 13 Apr 2018 10:26:26 +0100 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w3D9QQQH56688736; Fri, 13 Apr 2018 09:26:26 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B9AD4A4057; Fri, 13 Apr 2018 10:18:40 +0100 (BST) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 8B5ECA4051; Fri, 13 Apr 2018 10:18:40 +0100 (BST) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Fri, 13 Apr 2018 10:18:40 +0100 (BST) From: Steffen Maier To: linux-doc@vger.kernel.org Cc: Steffen Maier , Steven Rostedt , Ingo Molnar , Jonathan Corbet Subject: [PATCH] Documentation: ftrace: clarify filters with dynamic ftrace and graph Date: Fri, 13 Apr 2018 11:26:16 +0200 X-Mailer: git-send-email 2.13.5 X-TM-AS-GCONF: 00 x-cbid: 18041309-0040-0000-0000-0000042DE278 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18041309-0041-0000-0000-00002631FE77 Message-Id: <20180413092616.9239-1-maier@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-04-13_05:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1804130087 Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org I fell into the trap of having set up function tracer with a very limited filter and then switched over to function_graph and was erroneously wondering why the latter did not trace what I expected, which was the full unabridged graph recursion. Signed-off-by: Steffen Maier Cc: Steven Rostedt Cc: Ingo Molnar Cc: Jonathan Corbet Cc: linux-doc@vger.kernel.org --- Documentation/trace/ftrace.rst | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/Documentation/trace/ftrace.rst b/Documentation/trace/ftrace.rst index e45f0786f3f9..68835d062344 100644 --- a/Documentation/trace/ftrace.rst +++ b/Documentation/trace/ftrace.rst @@ -224,6 +224,7 @@ of ftrace. Here is a list of some of the key files: has a side effect of enabling or disabling specific functions to be traced. Echoing names of functions into this file will limit the trace to only those functions. + This influences both the tracers "function" and "function_graph"! The functions listed in "available_filter_functions" are what can be written into this file. @@ -265,6 +266,9 @@ of ftrace. Here is a list of some of the key files: Functions listed in this file will cause the function graph tracer to only trace these functions and the functions that they call. (See the section "dynamic ftrace" for more details). + With dynamic ftrace, the graph tracer can only trace functions that + set_ftrace_filter minus set_ftrace_notrace armed; this also influences + the ability to chase function call chains. set_graph_notrace: @@ -277,7 +281,8 @@ of ftrace. Here is a list of some of the key files: This lists the functions that ftrace has processed and can trace. These are the function names that you can pass to - "set_ftrace_filter" or "set_ftrace_notrace". + "set_ftrace_filter", "set_ftrace_notrace", + "set_graph_function", or "set_graph_notrace". (See the section "dynamic ftrace" below for more details.) dyn_ftrace_total_info: -- 2.13.5 -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html