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-rw-r--r--tools/perf/Documentation/perf-timechart.txt38
1 files changed, 36 insertions, 2 deletions
diff --git a/tools/perf/Documentation/perf-timechart.txt b/tools/perf/Documentation/perf-timechart.txt
index 5e0f986dff38..df98d1c82688 100644
--- a/tools/perf/Documentation/perf-timechart.txt
+++ b/tools/perf/Documentation/perf-timechart.txt
@@ -15,10 +15,20 @@ DESCRIPTION
There are two variants of perf timechart:
'perf timechart record <command>' to record the system level events
- of an arbitrary workload.
+ of an arbitrary workload. By default timechart records only scheduler
+ and CPU events (task switches, running times, CPU power states, etc),
+ but it's possible to record IO (disk, network) activity using -I argument.
'perf timechart' to turn a trace into a Scalable Vector Graphics file,
- that can be viewed with popular SVG viewers such as 'Inkscape'.
+ that can be viewed with popular SVG viewers such as 'Inkscape'. Depending
+ on the events in the perf.data file, timechart will contain scheduler/cpu
+ events or IO events.
+
+ In IO mode, every bar has two charts: upper and lower.
+ Upper bar shows incoming events (disk reads, ingress network packets).
+ Lower bar shows outgoing events (disk writes, egress network packets).
+ There are also poll bars which show how much time application spent
+ in poll/epoll/select syscalls.
TIMECHART OPTIONS
-----------------
@@ -54,6 +64,19 @@ TIMECHART OPTIONS
duration or tasks with given name. If number is given it's interpreted
as number of nanoseconds. If non-numeric string is given it's
interpreted as task name.
+--io-skip-eagain::
+ Don't draw EAGAIN IO events.
+--io-min-time=<nsecs>::
+ Draw small events as if they lasted min-time. Useful when you need
+ to see very small and fast IO. It's possible to specify ms or us
+ suffix to specify time in milliseconds or microseconds.
+ Default value is 1ms.
+--io-merge-dist=<nsecs>::
+ Merge events that are merge-dist nanoseconds apart.
+ Reduces number of figures on the SVG and makes it more render-friendly.
+ It's possible to specify ms or us suffix to specify time in
+ milliseconds or microseconds.
+ Default value is 1us.
RECORD OPTIONS
--------------
@@ -63,6 +86,9 @@ RECORD OPTIONS
-T::
--tasks-only::
Record only tasks-related events
+-I::
+--io-only::
+ Record only io-related events
-g::
--callchain::
Do call-graph (stack chain/backtrace) recording
@@ -87,6 +113,14 @@ Record system-wide timechart:
$ perf timechart --highlight gcc
+Record system-wide IO events:
+
+ $ perf timechart record -I
+
+ then generate timechart:
+
+ $ perf timechart
+
SEE ALSO
--------
linkperf:perf-record[1]