scheduler latency

scheduler latency

[Nick Piggin]

Hi,
I've done some scheduler latency tests and come up with some
pretty plots, so I thought I'd post them. It is nicksched vs
mainline.

Note: this is not realtime scheduling latency, but latency as
measured by my random program. It also does not indicate
interactivity, because the latencies measured were all under
15ms which is probably below perception. Even if not, it
doesn't measure latency as you might see it.

Finally, some of the tests involved me moving the mouse around,
so factor in by subliminal (or not) bias toward my scheduler.

http://www.kerneltrap.org/~npiggin/schedlat3/index.html

Re: scheduler latency

[Davide Libenzi]

On Thu, 29 Apr 2004, Nick Piggin wrote:

> I've done some scheduler latency tests and come up with some
> pretty plots, so I thought I'd post them. It is nicksched vs
> mainline.
> 
> Note: this is not realtime scheduling latency, but latency as
> measured by my random program. It also does not indicate
> interactivity, because the latencies measured were all under
> 15ms which is probably below perception. Even if not, it
> doesn't measure latency as you might see it.
> 
> Finally, some of the tests involved me moving the mouse around,
> so factor in by subliminal (or not) bias toward my scheduler.
> 
> http://www.kerneltrap.org/~npiggin/schedlat3/index.html

Nick, when I did the SOFTRR hack, I also measured sched latencies using 
another measurement/load apps:

http://www.xmailserver.org/linux-patches/softrr.html

At the bottom you can find the measurement app (note: x86 only since it 
uses "rdtsc") and stressful (latency-wise) loads.



- Davide