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authorSteven Rostedt (VMware) <rostedt@goodmis.org>2020-03-26 20:22:44 +0300
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2020-03-27 23:39:02 +0300
commit2ab2a0924b9980551ebe1c47d2a402a94efc1835 (patch)
tree9fdacfe0f1e5f2ddd0d12ee912d459a2ff6ca469 /Documentation/trace
parentebed9628f5c2101e1ab546de3b0742e0bb9eba3c (diff)
downloadlinux-2ab2a0924b9980551ebe1c47d2a402a94efc1835.tar.xz
tracing: Add documentation on set_ftrace_notrace_pid and set_event_notrace_pid
Update the tracing documentation to reflect the new files in the tracing directory. Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'Documentation/trace')
-rw-r--r--Documentation/trace/ftrace.rst31
1 files changed, 31 insertions, 0 deletions
diff --git a/Documentation/trace/ftrace.rst b/Documentation/trace/ftrace.rst
index 00621731bf27..3b5614b1d1a5 100644
--- a/Documentation/trace/ftrace.rst
+++ b/Documentation/trace/ftrace.rst
@@ -263,6 +263,20 @@ of ftrace. Here is a list of some of the key files:
traced by the function tracer as well. This option will also
cause PIDs of tasks that exit to be removed from the file.
+ set_ftrace_notrace_pid:
+
+ Have the function tracer ignore threads whose PID are listed in
+ this file.
+
+ If the "function-fork" option is set, then when a task whose
+ PID is listed in this file forks, the child's PID will
+ automatically be added to this file, and the child will not be
+ traced by the function tracer as well. This option will also
+ cause PIDs of tasks that exit to be removed from the file.
+
+ If a PID is in both this file and "set_ftrace_pid", then this
+ file takes precedence, and the thread will not be traced.
+
set_event_pid:
Have the events only trace a task with a PID listed in this file.
@@ -274,6 +288,19 @@ of ftrace. Here is a list of some of the key files:
cause the PIDs of tasks to be removed from this file when the task
exits.
+ set_event_notrace_pid:
+
+ Have the events not trace a task with a PID listed in this file.
+ Note, sched_switch and sched_wakeup will trace threads not listed
+ in this file, even if a thread's PID is in the file if the
+ sched_switch or sched_wakeup events also trace a thread that should
+ be traced.
+
+ To have the PIDs of children of tasks with their PID in this file
+ added on fork, enable the "event-fork" option. That option will also
+ cause the PIDs of tasks to be removed from this file when the task
+ exits.
+
set_graph_function:
Functions listed in this file will cause the function graph
@@ -1183,6 +1210,8 @@ Here are the available options:
tasks fork. Also, when tasks with PIDs in set_event_pid exit,
their PIDs will be removed from the file.
+ This affects PIDs listed in set_event_notrace_pid as well.
+
function-trace
The latency tracers will enable function tracing
if this option is enabled (default it is). When
@@ -1197,6 +1226,8 @@ Here are the available options:
set_ftrace_pid exit, their PIDs will be removed from the
file.
+ This affects PIDs in set_ftrace_notrace_pid as well.
+
display-graph
When set, the latency tracers (irqsoff, wakeup, etc) will
use function graph tracing instead of function tracing.