Re: [PATCH] Preemption Latency Measurement Tool

Robert Love
2001-09-23T02:45:42Z

On Sat, 2001-09-22 at 17:09, Dieter Nützel wrote:
> Yes, I do like I've posted in all the related threads.
>
> Here is some more input for you. I hope it could help nail it down.
>
> Regards,
> Dieter
>
> BTW I'll now switching to 2.4.10-pre14
>
> SunWave1#time tar xIf /Pakete/Linux/linux-2.4.9.tar.bz2
> 34.570u 5.350s 0:47.84 83.4% 0+0k 0+0io 295pf+0w
>
> I "hear" some have disk activities (disk trashing).
>
> SunWave1#sync
>
> Runs for ages!!!

It has to flush that whole tar job you just did, which it did in memory
:)

> User CPU 0%
> System CPU 0%
> Idle CPU 99%
>
> So where did it wait???
>
> Here comes what latencytimes show:
>
> Worst 20 latency times of 5061 measured in this period.
> usec cause mask start line/file address end line/file
> 322263 reacqBKL 1 1375/sched.c c01138b4 697/sched.c
> 216174 BKL 1 30/inode.c c016b971 52/inode.c
> 158328 BKL 9 742/block_dev.c c0144d51 697/sched.c

OK, these three are not acceptable...adding them to the "list".

--
Robert M. Love
rml at ufl.edu
rml at tech9.net