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authorChase Douglas <chase.douglas@canonical.com>2010-04-23 14:02:39 -0400
committerSteven Rostedt <rostedt@goodmis.org>2010-04-27 16:51:49 -0400
commit07271aa42d13378e67ebd79ea9ca1c4a5e2ad46f (patch)
tree7698e567d269f140019bd2e275cd44aefd2826b9 /Documentation
parenta838b2e634405fb89ddbf4fa9412acb33911911f (diff)
tracing: Add documentation for trace commands mod, traceon/traceoff
The mod command went in as commit 64e7c440618998fd69eee6ab490b042d12248021 The traceon/traceoff commands went in as commit 23b4ff3aa479c9e3bb23cb6b2d0a97878399784a Signed-off-by: Chase Douglas <chase.douglas@canonical.com> LKML-Reference: <1272045759-32018-1-git-send-email-chase.douglas@canonical.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/trace/ftrace.txt44
1 files changed, 44 insertions, 0 deletions
diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt
index 52011815c905..557c1edeccaf 100644
--- a/Documentation/trace/ftrace.txt
+++ b/Documentation/trace/ftrace.txt
@@ -155,6 +155,9 @@ of ftrace. Here is a list of some of the key files:
155 to be traced. Echoing names of functions into this file 155 to be traced. Echoing names of functions into this file
156 will limit the trace to only those functions. 156 will limit the trace to only those functions.
157 157
158 This interface also allows for commands to be used. See the
159 "Filter commands" section for more details.
160
158 set_ftrace_notrace: 161 set_ftrace_notrace:
159 162
160 This has an effect opposite to that of 163 This has an effect opposite to that of
@@ -1824,6 +1827,47 @@ this special filter via:
1824 echo > set_graph_function 1827 echo > set_graph_function
1825 1828
1826 1829
1830Filter commands
1831---------------
1832
1833A few commands are supported by the set_ftrace_filter interface.
1834Trace commands have the following format:
1835
1836<function>:<command>:<parameter>
1837
1838The following commands are supported:
1839
1840- mod
1841 This command enables function filtering per module. The
1842 parameter defines the module. For example, if only the write*
1843 functions in the ext3 module are desired, run:
1844
1845 echo 'write*:mod:ext3' > set_ftrace_filter
1846
1847 This command interacts with the filter in the same way as
1848 filtering based on function names. Thus, adding more functions
1849 in a different module is accomplished by appending (>>) to the
1850 filter file. Remove specific module functions by prepending
1851 '!':
1852
1853 echo '!writeback*:mod:ext3' >> set_ftrace_filter
1854
1855- traceon/traceoff
1856 These commands turn tracing on and off when the specified
1857 functions are hit. The parameter determines how many times the
1858 tracing system is turned on and off. If unspecified, there is
1859 no limit. For example, to disable tracing when a schedule bug
1860 is hit the first 5 times, run:
1861
1862 echo '__schedule_bug:traceoff:5' > set_ftrace_filter
1863
1864 These commands are cumulative whether or not they are appended
1865 to set_ftrace_filter. To remove a command, prepend it by '!'
1866 and drop the parameter:
1867
1868 echo '!__schedule_bug:traceoff' > set_ftrace_filter
1869
1870
1827trace_pipe 1871trace_pipe
1828---------- 1872----------
1829 1873