diff options
Diffstat (limited to 'Documentation/trace/ftrace.txt')
| -rw-r--r-- | Documentation/trace/ftrace.txt | 34 |
1 files changed, 24 insertions, 10 deletions
diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt index f52f297cb406..fdf18485db2b 100644 --- a/Documentation/trace/ftrace.txt +++ b/Documentation/trace/ftrace.txt @@ -210,6 +210,11 @@ of ftrace. Here is a list of some of the key files: Note, sched_switch and sched_wake_up will also trace events listed in this file. + 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: Set a "trigger" function where tracing should start @@ -725,16 +730,14 @@ noraw nohex nobin noblock -nostacktrace trace_printk -noftrace_preempt nobranch annotate nouserstacktrace nosym-userobj noprintk-msg-only context-info -latency-format +nolatency-format sleep-time graph-time record-cmd @@ -742,7 +745,10 @@ overwrite nodisable_on_free irq-info markers +noevent-fork function-trace +nodisplay-graph +nostacktrace To disable one of the options, echo in the option prepended with "no". @@ -796,11 +802,6 @@ Here are the available options: block - When set, reading trace_pipe will not block when polled. - stacktrace - This is one of the options that changes the trace - itself. When a trace is recorded, so is the stack - of functions. This allows for back traces of - trace sites. - trace_printk - Can disable trace_printk() from writing into the buffer. branch - Enable branch tracing with the tracer. @@ -897,6 +898,10 @@ x494] <- /root/a.out[+0x4a8] <- /lib/libc-2.7.so[+0x1e1a6] When disabled, the trace_marker will error with EINVAL on write. + event-fork - When set, tasks with PIDs listed in set_event_pid will have + the PIDs of their children added to set_event_pid when those + tasks fork. Also, when tasks with PIDs in set_event_pid exit, + their PIDs will be removed from the file. function-trace - The latency tracers will enable function tracing if this option is enabled (default it is). When @@ -904,8 +909,17 @@ x494] <- /root/a.out[+0x4a8] <- /lib/libc-2.7.so[+0x1e1a6] functions. This keeps the overhead of the tracer down when performing latency tests. - Note: Some tracers have their own options. They only appear - when the tracer is active. + display-graph - When set, the latency tracers (irqsoff, wakeup, etc) will + use function graph tracing instead of function tracing. + + stacktrace - This is one of the options that changes the trace + itself. When a trace is recorded, so is the stack + of functions. This allows for back traces of + trace sites. + + Note: Some tracers have their own options. They only appear in this + file when the tracer is active. They always appear in the + options directory. |