aboutsummaryrefslogtreecommitdiffstats
path: root/Documentation
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2010-05-18 11:35:04 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2010-05-18 11:35:04 -0400
commit752f114fb83c5839de37a250b4f8257ed5438341 (patch)
treec565c3b6670d21ad7f5cd6cdda5864a76d3f2e0c /Documentation
parentb8ae30ee26d379db436b0b8c8c3ff1b52f69e5d1 (diff)
parentad56b0797e67df5e04b2f1a1e02900145c5c16f2 (diff)
Merge branch 'tracing-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'tracing-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: tracing: Fix "integer as NULL pointer" warning. tracing: Fix tracepoint.h DECLARE_TRACE() to allow more than one header tracing: Make the documentation clear on trace_event boot option ring-buffer: Wrap open-coded WARN_ONCE tracing: Convert nop macros to static inlines tracing: Fix sleep time function profiling tracing: Show sample std dev in function profiling tracing: Add documentation for trace commands mod, traceon/traceoff ring-buffer: Make benchmark handle missed events ring-buffer: Make non-consuming read less expensive with lots of cpus. tracing: Add graph output support for irqsoff tracer tracing: Have graph flags passed in to ouput functions tracing: Add ftrace events for graph tracer tracing: Dump either the oops's cpu source or all cpus buffers tracing: Fix uninitialized variable of tracing/trace output
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/kernel-parameters.txt6
-rw-r--r--Documentation/trace/events.txt3
-rw-r--r--Documentation/trace/ftrace.txt50
3 files changed, 55 insertions, 4 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 0c6c56076d19..567b7a8eb878 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -786,8 +786,12 @@ and is between 256 and 4096 characters. It is defined in the file
786 as early as possible in order to facilitate early 786 as early as possible in order to facilitate early
787 boot debugging. 787 boot debugging.
788 788
789 ftrace_dump_on_oops 789 ftrace_dump_on_oops[=orig_cpu]
790 [FTRACE] will dump the trace buffers on oops. 790 [FTRACE] will dump the trace buffers on oops.
791 If no parameter is passed, ftrace will dump
792 buffers of all CPUs, but if you pass orig_cpu, it will
793 dump only the buffer of the CPU that triggered the
794 oops.
791 795
792 ftrace_filter=[function-list] 796 ftrace_filter=[function-list]
793 [FTRACE] Limit the functions traced by the function 797 [FTRACE] Limit the functions traced by the function
diff --git a/Documentation/trace/events.txt b/Documentation/trace/events.txt
index 02ac6ed38b2d..778ddf38b82c 100644
--- a/Documentation/trace/events.txt
+++ b/Documentation/trace/events.txt
@@ -90,7 +90,8 @@ In order to facilitate early boot debugging, use boot option:
90 90
91 trace_event=[event-list] 91 trace_event=[event-list]
92 92
93The format of this boot option is the same as described in section 2.1. 93event-list is a comma separated list of events. See section 2.1 for event
94format.
94 95
953. Defining an event-enabled tracepoint 963. Defining an event-enabled tracepoint
96======================================= 97=======================================
diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt
index 03485bfbd797..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
@@ -1337,12 +1340,14 @@ ftrace_dump_on_oops must be set. To set ftrace_dump_on_oops, one
1337can either use the sysctl function or set it via the proc system 1340can either use the sysctl function or set it via the proc system
1338interface. 1341interface.
1339 1342
1340 sysctl kernel.ftrace_dump_on_oops=1 1343 sysctl kernel.ftrace_dump_on_oops=n
1341 1344
1342or 1345or
1343 1346
1344 echo 1 > /proc/sys/kernel/ftrace_dump_on_oops 1347 echo n > /proc/sys/kernel/ftrace_dump_on_oops
1345 1348
1349If n = 1, ftrace will dump buffers of all CPUs, if n = 2 ftrace will
1350only dump the buffer of the CPU that triggered the oops.
1346 1351
1347Here's an example of such a dump after a null pointer 1352Here's an example of such a dump after a null pointer
1348dereference in a kernel module: 1353dereference in a kernel module:
@@ -1822,6 +1827,47 @@ this special filter via:
1822 echo > set_graph_function 1827 echo > set_graph_function
1823 1828
1824 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
1825trace_pipe 1871trace_pipe
1826---------- 1872----------
1827 1873