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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) <[email protected]>
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Documentation/trace/ftrace.rst

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@@ -263,6 +263,20 @@ of ftrace. Here is a list of some of the key files:
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traced by the function tracer as well. This option will also
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cause PIDs of tasks that exit to be removed from the file.
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set_ftrace_notrace_pid:
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Have the function tracer ignore threads whose PID are listed in
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this file.
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If the "function-fork" option is set, then when a task whose
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PID is listed in this file forks, the child's PID will
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automatically be added to this file, and the child will not be
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traced by the function tracer as well. This option will also
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cause PIDs of tasks that exit to be removed from the file.
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If a PID is in both this file and "set_ftrace_pid", then this
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file takes precedence, and the thread will not be traced.
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set_event_pid:
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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:
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cause the PIDs of tasks to be removed from this file when the task
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exits.
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set_event_notrace_pid:
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Have the events not trace a task with a PID listed in this file.
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Note, sched_switch and sched_wakeup will trace threads not listed
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in this file, even if a thread's PID is in the file if the
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sched_switch or sched_wakeup events also trace a thread that should
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be traced.
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To have the PIDs of children of tasks with their PID in this file
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added on fork, enable the "event-fork" option. That option will also
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cause the PIDs of tasks to be removed from this file when the task
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exits.
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set_graph_function:
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Functions listed in this file will cause the function graph
@@ -1183,6 +1210,8 @@ Here are the available options:
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tasks fork. Also, when tasks with PIDs in set_event_pid exit,
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their PIDs will be removed from the file.
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This affects PIDs listed in set_event_notrace_pid as well.
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function-trace
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The latency tracers will enable function tracing
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if this option is enabled (default it is). When
@@ -1197,6 +1226,8 @@ Here are the available options:
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set_ftrace_pid exit, their PIDs will be removed from the
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file.
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This affects PIDs in set_ftrace_notrace_pid as well.
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display-graph
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When set, the latency tracers (irqsoff, wakeup, etc) will
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use function graph tracing instead of function tracing.

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