Messages in this thread | | | From | Namhyung Kim <> | Subject | Re: [for-next][PATCH 9/9] tracing: Update debugfs README file | Date | Mon, 18 Mar 2013 17:22:31 +0900 |
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Hi Steve,
On Fri, 15 Mar 2013 23:24:21 -0400, Steven Rostedt wrote: > From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org> > > Update the README file in debugfs/tracing to something more useful. > What's currently in the file is very old and what it shows doesn't > have much use. Heck, it tells you how to mount debugfs! But to read > this file you would have already needed to mount it. > > Replace the file with current up-to-date information. It's rather > limited, but what do you expect from a pseudo README file. > > Signed-off-by: Steven Rostedt <rostedt@goodmis.org> > --- > kernel/trace/trace.c | 89 ++++++++++++++++++++++++++++++++++++++++++-------- > 1 file changed, 75 insertions(+), 14 deletions(-) > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index 3dc7999..83ad596 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -3300,20 +3300,81 @@ static const struct file_operations tracing_iter_fops = { > > static const char readme_msg[] = > "tracing mini-HOWTO:\n\n" > - "# mount -t debugfs nodev /sys/kernel/debug\n\n" > - "# cat /sys/kernel/debug/tracing/available_tracers\n" > - "wakeup wakeup_rt preemptirqsoff preemptoff irqsoff function nop\n\n" > - "# cat /sys/kernel/debug/tracing/current_tracer\n" > - "nop\n" > - "# echo wakeup > /sys/kernel/debug/tracing/current_tracer\n" > - "# cat /sys/kernel/debug/tracing/current_tracer\n" > - "wakeup\n" > - "# cat /sys/kernel/debug/tracing/trace_options\n" > - "noprint-parent nosym-offset nosym-addr noverbose\n" > - "# echo print-parent > /sys/kernel/debug/tracing/trace_options\n" > - "# echo 1 > /sys/kernel/debug/tracing/tracing_on\n" > - "# cat /sys/kernel/debug/tracing/trace > /tmp/trace.txt\n" > - "# echo 0 > /sys/kernel/debug/tracing/tracing_on\n" > + "# echo 0 > tracing_on : quick way to disable tracing\n" > + "# echo 1 > tracing_on : quick way to re-enable tracing\n\n" > + " Important files:\n" > + " trace\t\t\t- The static contents of the buffer\n" > + "\t\t\t To clear the buffer write into this file: echo > trace\n" > + " trace_pipe\t\t- A consuming read to see the contents of the buffer\n" > + " current_tracer\t- function and latency tracers\n" > + " available_tracers\t- list of configured tracers for current_tracer\n" > + " buffer_size_kb\t- view and modify size of per cpu buffer\n" > + " buffer_total_size_kb - view total size of all cpu buffers\n\n" > + " trace_clock\t\t-change the clock used to order events\n" > + " local: Per cpu clock but may not be synced across CPUS\n" > + " global: Synced across CPUs but slows tracing down.\n" > + " counter: Not a clock, but just an increment\n" > + " uptime: Jiffy counter from time of boot\n" > + " perf: Same clock that perf events use\n" > +#ifdef CONFIG_X86_64 > + " x86-tsc: TSC cycle counter\n" > +#endif > + "\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n" > + " tracing_cpumask\t- Limit which CPUs to trace\n" > + " instances\t\t- Make sub-buffers with: mkdir instances/foo\n" > + "\t\t\t Remove sub-buffer with rmdir\n" > + " trace_options\t\t- Set format or modify how tracing happens\n" > + "\t\t\t Disable an option by adding a suffix 'no' to the option name\n" > +#ifdef CONFIG_DYNAMIC_FTRACE > + "\n available_filter_functions - list of functions that can be filtered on\n" > + " set_ftrace_filter\t- echo function name in here to only trace these functions\n" > + " accepts: func_full_name, *func_end, func_begin*, *func_middle*\n" > + " modules: Can select a group via module\n" > + " Format: :mod:<module-name>\n" > + " example: echo :mod:ext3 > set_ftrace_filter\n" > + " triggers: a command to perform when function is hit\n" > + " Format: <function>:<trigger>[:count]\n" > + " trigger: traceon, traceoff\n" > + " enable_event:<system>:<event>\n" > + " disable_event:<system>:<event>\n" > +#ifdef CONFIG_STACKTRACE > + " stacktrace\n" > +#endif > +#ifdef CONFIG_TRACER_SNAPSHOT > + " snapshot\n" > +#endif > + " example: echo do_fault:traceoff > set_ftrace_filter\n" > + " echo do_trap:traceoff:3 > set_ftrace_filter\n" > + " The first one will disable tracing everytime do_fault is hit\n" > + " The second will disable tracing at most 3 times whne do_trap is hit\n"
s/whne/when/
It's slightly confusing for me to read the "at most" part. Did you mean it by "The second will disable tracing after do_trace is hit 3 times"?
Thanks, Namhyung
> + " To remove trigger without count:\n" > + " echo '!<function>:<trigger> > set_ftrace_filter\n" > + " To remove trigger with a count:\n" > + " echo '!<function>:<trigger>:0 > set_ftrace_filter\n" > + " set_ftrace_notrace\t- echo function name in here to never trace.\n" > + " accepts: func_full_name, *func_end, func_begin*, *func_middle*\n" > + " modules: Can select a group via module command :mod:\n" > + " Does not accept triggers\n" > +#endif /* CONFIG_DYNAMIC_FTRACE */ > +#ifdef CONFIG_FUNCTION_TRACER > + " set_ftrace_pid\t- Write pid(s) to only function trace those pids (function)\n" > +#endif > +#ifdef CONFIG_FUNCTION_GRAPH_TRACER > + " set_graph_function\t- Trace the nested calls of a function (function_graph)\n" > + " max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n" > +#endif > +#ifdef CONFIG_TRACER_SNAPSHOT > + "\n snashot\t\t- Like 'trace' but shows the content of the static snapshot buffer\n" > + "\t\t\t Read the contents for more infromation\n" > +#endif > +#ifdef CONFIG_STACKTRACE > + " stack_trace\t\t- Shows the max stack trace when active\n" > + " stack_max_size\t- Shows current max stack size that was traced\n" > + "\t\t\t Write into this file to reset the max size (trigger a new trace)\n" > +#ifdef CONFIG_DYNAMIC_FTRACE > + " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace traces\n" > +#endif > +#endif /* CONFIG_STACKTRACE */ > ; > > static ssize_t
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