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| author | Changbin Du <changbin.du@intel.com> | 2018-02-17 13:39:45 +0800 |
|---|---|---|
| committer | Jonathan Corbet <corbet@lwn.net> | 2018-03-07 10:26:02 -0700 |
| commit | 15ba053871bfb88472d38eff8257d195ac74ceda (patch) | |
| tree | 7d299c58c518345a90236926171d4a6237e14935 /Documentation/trace | |
| parent | 47e073d2adcc73f4ad275f17af440d72ba652c2c (diff) | |
| download | linux-15ba053871bfb88472d38eff8257d195ac74ceda.tar.gz linux-15ba053871bfb88472d38eff8257d195ac74ceda.tar.bz2 linux-15ba053871bfb88472d38eff8257d195ac74ceda.zip | |
trace doc: convert trace/events-nmi.txt to rst format
This converts the plain text documentation to reStructuredText format and
add it into Sphinx TOC tree. No essential content change.
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Changbin Du <changbin.du@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'Documentation/trace')
| -rw-r--r-- | Documentation/trace/events-nmi.rst | 45 | ||||
| -rw-r--r-- | Documentation/trace/events-nmi.txt | 43 | ||||
| -rw-r--r-- | Documentation/trace/index.rst | 1 |
3 files changed, 46 insertions, 43 deletions
diff --git a/Documentation/trace/events-nmi.rst b/Documentation/trace/events-nmi.rst new file mode 100644 index 000000000000..9e0a7289d80a --- /dev/null +++ b/Documentation/trace/events-nmi.rst @@ -0,0 +1,45 @@ +================ +NMI Trace Events +================ + +These events normally show up here: + + /sys/kernel/debug/tracing/events/nmi + + +nmi_handler +----------- + +You might want to use this tracepoint if you suspect that your +NMI handlers are hogging large amounts of CPU time. The kernel +will warn if it sees long-running handlers:: + + INFO: NMI handler took too long to run: 9.207 msecs + +and this tracepoint will allow you to drill down and get some +more details. + +Let's say you suspect that perf_event_nmi_handler() is causing +you some problems and you only want to trace that handler +specifically. You need to find its address:: + + $ grep perf_event_nmi_handler /proc/kallsyms + ffffffff81625600 t perf_event_nmi_handler + +Let's also say you are only interested in when that function is +really hogging a lot of CPU time, like a millisecond at a time. +Note that the kernel's output is in milliseconds, but the input +to the filter is in nanoseconds! You can filter on 'delta_ns':: + + cd /sys/kernel/debug/tracing/events/nmi/nmi_handler + echo 'handler==0xffffffff81625600 && delta_ns>1000000' > filter + echo 1 > enable + +Your output would then look like:: + + $ cat /sys/kernel/debug/tracing/trace_pipe + <idle>-0 [000] d.h3 505.397558: nmi_handler: perf_event_nmi_handler() delta_ns: 3236765 handled: 1 + <idle>-0 [000] d.h3 505.805893: nmi_handler: perf_event_nmi_handler() delta_ns: 3174234 handled: 1 + <idle>-0 [000] d.h3 506.158206: nmi_handler: perf_event_nmi_handler() delta_ns: 3084642 handled: 1 + <idle>-0 [000] d.h3 506.334346: nmi_handler: perf_event_nmi_handler() delta_ns: 3080351 handled: 1 + diff --git a/Documentation/trace/events-nmi.txt b/Documentation/trace/events-nmi.txt deleted file mode 100644 index c03c8c89f08d..000000000000 --- a/Documentation/trace/events-nmi.txt +++ /dev/null @@ -1,43 +0,0 @@ -NMI Trace Events - -These events normally show up here: - - /sys/kernel/debug/tracing/events/nmi - --- - -nmi_handler: - -You might want to use this tracepoint if you suspect that your -NMI handlers are hogging large amounts of CPU time. The kernel -will warn if it sees long-running handlers: - - INFO: NMI handler took too long to run: 9.207 msecs - -and this tracepoint will allow you to drill down and get some -more details. - -Let's say you suspect that perf_event_nmi_handler() is causing -you some problems and you only want to trace that handler -specifically. You need to find its address: - - $ grep perf_event_nmi_handler /proc/kallsyms - ffffffff81625600 t perf_event_nmi_handler - -Let's also say you are only interested in when that function is -really hogging a lot of CPU time, like a millisecond at a time. -Note that the kernel's output is in milliseconds, but the input -to the filter is in nanoseconds! You can filter on 'delta_ns': - -cd /sys/kernel/debug/tracing/events/nmi/nmi_handler -echo 'handler==0xffffffff81625600 && delta_ns>1000000' > filter -echo 1 > enable - -Your output would then look like: - -$ cat /sys/kernel/debug/tracing/trace_pipe -<idle>-0 [000] d.h3 505.397558: nmi_handler: perf_event_nmi_handler() delta_ns: 3236765 handled: 1 -<idle>-0 [000] d.h3 505.805893: nmi_handler: perf_event_nmi_handler() delta_ns: 3174234 handled: 1 -<idle>-0 [000] d.h3 506.158206: nmi_handler: perf_event_nmi_handler() delta_ns: 3084642 handled: 1 -<idle>-0 [000] d.h3 506.334346: nmi_handler: perf_event_nmi_handler() delta_ns: 3080351 handled: 1 - diff --git a/Documentation/trace/index.rst b/Documentation/trace/index.rst index 309c9c5b85a0..f4a8fbca4fb4 100644 --- a/Documentation/trace/index.rst +++ b/Documentation/trace/index.rst @@ -15,3 +15,4 @@ Linux Tracing Technologies events events-kmem events-power + events-nmi |