Messages in this thread | | | From | Darren Hart <> | Subject | Re: rt20 scheduling latency testcase and failure data | Date | Thu, 18 May 2006 02:38:32 -0700 |
| |
On Thursday 18 May 2006 01:58, Sébastien Dugué wrote: > On Thu, 2006-05-18 at 10:47 +0200, Ingo Molnar wrote: > > * Sébastien Dugué <sebastien.dugue@bull.net> wrote: > > > Darren, > > > > > > On Mon, 2006-05-15 at 18:30 -0700, Darren Hart wrote: > > > > Following Ingo's example I have included the modified test case > > > > (please see the original mail for librt.h) that starts the trace > > > > before each sleep and disables it after we wake up. If we have > > > > missed a period, we print the trace. > > > > > > Your test program fails (at least on my box) as the overhead of > > > starting and stopping the trace in the 5 ms period is just too high. > > > > > > By moving the latency_trace_start() at the start of the thread > > > function and latency_trace_stop() at the end, everything runs fine. I > > > did not have any period missed even under heavy load. > > > > could you send us the fixed testcase? > > No problem, see attachment.
I found several similar problems in my original test case, please see my earlier mail from today where I included a completely rewritten test case with buffered output and new periodic logic.
The case attached here seems to try to print the trace without first stopping it. I don't think that will result in the desired output. My new test case addresses that issue as well.
I'd appreciate any feedback, thanks.
-- Darren Hart IBM Linux Technology Center Realtime Linux Team Phone: 503 578 3185 T/L: 775 3185 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |