Re: 2.6.8-rc3-mm2

Martin J. Bligh
2004-08-10T21:37:54Z

> - Added a little patch to the CPU scheduler which disables its array
> switching.
>
> This is purely experimental and will cause high-priority tasks
> to starve lower-priority tasks indefinitely. It is here to
> determine whether it is this aspect of the scheduler which caused
> the staircase scheduler to exhibit improved throughput in some
> tests on NUMAq.
>
> Here's the results of tests with sdet. The summary is that yes, we
> did reach the peak we saw with the staircase scheduler (2.6.8-rc2-mm2).
> Dropping the expired array does make a difference. But it looks like
> that wasn't all of it, though, because we see it fails to reach the same
> scores in all *but* the peak run.

Eh? what's the peak run? the one out of 10 with best performace. Oddly,
what you're seeing doesn't match what I'm seeing at all ... I'm looking
at average runtime. SDET is fairly variable - I don't think looking at
the best run is a good idea.

> Overall, I'd say I still like the staircase patch as a whole. Not only
> did it increase the benchmark numbers, but I like the simplicity it
> (re)introduces for interactive bonus calculations.

Me too.

> Sdet
> Scripts 1 4 16 64
> 2.6.8-rc2-mm2 32.46% 58.58% 100.00% 74.20%
> 2.6.8-rc2-mm2-noscase 23.62% 43.95% 90.92% 74.16%
> 2.6.8-rc3-mm2 16.44% 43.26% 102.95% 71.26%

Very odd. would suggest you do a few more runs - for 4 scripts,
you're matching the results of nostaircase, for 16, without it.

SDET 1 (see disclaimer)
Throughput Std. Dev
2.6.8-rc2 100.0% 2.3%
2.6.8-rc2-mm2-oldsched 100.2% 0.4%
2.6.8-rc2-mm2 116.2% 3.3%
2.6.8-rc3-mm2 102.9% 1.9%

SDET 2 (see disclaimer)
Throughput Std. Dev
2.6.8-rc2 100.0% 1.4%
2.6.8-rc2-mm2-oldsched 98.2% 1.0%
2.6.8-rc2-mm2 114.5% 4.0%
2.6.8-rc3-mm2 100.5% 1.3%

SDET 4 (see disclaimer)
Throughput Std. Dev
2.6.8-rc2 100.0% 1.1%
2.6.8-rc2-mm2-oldsched 101.2% 0.3%
2.6.8-rc2-mm2 112.8% 0.5%
2.6.8-rc3-mm2 99.2% 0.8%

SDET 8 (see disclaimer)
Throughput Std. Dev
2.6.8-rc2 100.0% 1.0%
2.6.8-rc2-mm2-oldsched 100.5% 0.4%
2.6.8-rc2-mm2 117.2% 0.9%
2.6.8-rc3-mm2 101.7% 0.6%

SDET 16 (see disclaimer)
Throughput Std. Dev
2.6.8-rc2 100.0% 0.3%
2.6.8-rc2-mm2-oldsched 104.3% 0.5%
2.6.8-rc2-mm2 119.1% 0.6%
2.6.8-rc3-mm2 103.4% 0.2%

SDET 32 (see disclaimer)
Throughput Std. Dev
2.6.8-rc2 100.0% 0.4%
2.6.8-rc2-mm2-oldsched 101.2% 0.1%
2.6.8-rc2-mm2 102.4% 0.8%
2.6.8-rc3-mm2 99.2% 0.4%

SDET 64 (see disclaimer)
Throughput Std. Dev
2.6.8-rc2 100.0% 0.4%
2.6.8-rc2-mm2-oldsched 99.6% 0.0%
2.6.8-rc2-mm2 101.6% 0.0%
2.6.8-rc3-mm2 100.0% 0.4%

SDET 128 (see disclaimer)
Throughput Std. Dev
2.6.8-rc2 100.0% 0.1%
2.6.8-rc2-mm2-oldsched 101.7% 0.1%
2.6.8-rc2-mm2 102.8% 0.3%
2.6.8-rc3-mm2 104.5% 0.5%