Re: [BUG] Strange 1-second pauses during Resume-from-RAM

Jörn Engel
2007-12-02T20:35:53Z

On Sun, 2 December 2007 21:07:22 +0100, Ingo Molnar wrote:
> * Jörn Engel <joern@logfs.org> wrote:
>
> > Result looked like a livelock and finally convinced me to abandon the
> > latency tracer. Sorry, but it appears to be the right tool for the
> > wrong job.
>
> hm, we routinely use it in -rt to capture "what on earth is happening"
> incidents. The snippet below is a random snipped from a trace that i've
> just captured, with mcount enabled. It seems to work fine here, with and
> without mcount. (pit clocksource is almost never used, that's why you
> had those early problems.)
>
> oprofile helps if you can reliably reproduce the slowdown in a loop or
> for a long amount of time, with lots of CPU utilization - and then it's
> also lower overhead. The tracer can be used to capture rare or complex
> events, and gives the full flow control and what is happening within the
> kernel.

Such a trace would be useful indeed. But so far the patch has only
given me grief and nothing remotely like useful output. Maybe I should
simply use the complete -rt patch instead of debugging the broken-out
latency-tracer patch.

Jörn

--
Mundie uses a textbook tactic of manipulation: start with some
reasonable talk, and lead the audience to an unreasonable conclusion.
-- Bruce Perens