On Sun, 2 December 2007 21:07:22 +0100, Ingo Molnar wrote: > * Jörn Engel <[EMAIL PROTECTED]> 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
