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Re: [PATCH -tip 3/3] Add get_signal tracepoint


Ingo Molnar wrote:
Especially if you call this "get" rather than "deliver", there is
another place that should invoke this tracepoint (or perhaps a third
one).  sys_rt_sigtimedwait "gets" a signal without delivering it.  In
POSIX terminology this is called "accepting" the signal: the three
things that can happen in the life of a signal are "generate",
"deliver", and "accept".  If you are trying to match up what happened
to a signal generated by kill() or whatnot, then you want to notice
both delivery and acceptance as the complementary event.

(And again I have no clue why this signal stuff should be called
"sched" at all.)

it shouldnt be called 'sched' - it should go into 'events/signal.h'.


But we also need fuller coverage than this. Coredumps and signal
delivery events are just a small part of all things signals, we also
want:

That's a good idea. I'll put coredump and signal related events into events/signal.h.


- signal generation events (send_sig*() variants)

Those events finally calls __send_signal(), so I think trace_signal_send() can trace those events.

- signal IPI/wakeup events

All signals might be used for IPI, isn't it? :-) Or, did you mean SIGSTOP/SIGCONT pare?

- signal loss events (queue overflow)

Perhaps, this event is only for rt-signals, since legacy signals just overwritten if it was sent.

Thank you,

--
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division

e-mail: mhiramat@redhat.com


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