On Fri, 2009-03-20 at 18:42 -0700, Roland McGrath wrote:
> From: Frank Ch. Eigler <[email protected]>
> Here's the /debugfs/tracing/process_trace_README:
>
> process event tracer mini-HOWTO
>
> 1. Select process hierarchy to monitor. Other processes will be
> completely unaffected. Leave at 0 for system-wide tracing.
> % echo NNN > process_follow_pid
>
> 2. Determine which process event traces are potentially desired.
> syscall and signal tracing slow down monitored processes.
> % echo 0 > process_trace_{syscalls,signals,lifecycle}
>
> 3. Add any final uid- or taskcomm-based filtering. Non-matching
> processes will skip trace messages, but will still be slowed.
> % echo NNN > process_trace_uid_filter # -1: unrestricted
> % echo ls > process_trace_taskcomm_filter # empty: unrestricted
>
> 4. Start tracing.
> % echo process > current_tracer
>
> 5. Examine trace.
> % cat trace
>
> 6. Stop tracing.
> % echo nop > current_tracer
>
> Signed-off-by: Frank Ch. Eigler <[email protected]>
...
> +static char README_text[] =
> + "process event tracer mini-HOWTO\n"
> + "\n"
> + "1. Select process hierarchy to monitor. Other processes will be\n"
> + " completely unaffected. Leave at 0 for system-wide tracing.\n"
> + "# echo NNN > process_follow_pid\n"
> + "\n"
> + "2. Determine which process event traces are potentially desired.\n"
> + " syscall and signal tracing slow down monitored processes.\n"
> + "# echo 0 > process_trace_{syscalls,signals,lifecycle}\n"
> + "\n"
> + "3. Add any final uid- or taskcomm-based filtering. Non-matching\n"
> + " processes will skip trace messages, but will still be slowed.\n"
> + "# echo NNN > process_trace_uid_filter # -1: unrestricted \n"
> + "# echo ls > process_trace_taskcomm_filter # empty: unrestricted\n"
> + "\n"
> + "4. Start tracing.\n"
> + "# echo process > current_tracer\n"
> + "\n"
> + "5. Examine trace.\n"
> + "# cat trace\n"
> + "\n"
> + "6. Stop tracing.\n"
> + "# echo nop > current_tracer\n"
> + ;
A HOWTO text in the kernel binary? Shouldn't it be in Documentation/*
instead? But then, I am a well known miniaturization freak...
--
vda
