Re: Linux 2.6.23

From: Bill Davidsen
Date: Fri Oct 12 2007 - 08:14:55 EST


Ingo Molnar wrote:
* Nick Piggin <nickpiggin@xxxxxxxxxxxx> wrote:

;) I think you snipped the important bit:

"the peak is terrible but it has virtually no dropoff and performs better under load than the default 2.6.21 scheduler." (verbatim)

hm, i understood that peak remark to be in reference to FreeBSD's scheduler (which the FreeBSD guys are primarily interested in obviously), not v2.6.21 - but i could be wrong.

In any case, there is indeed a regression with sysbench and a low number of threads, and it's being fixed. The peak got improved visibly in sched-devel:

http://people.redhat.com/mingo/misc/sysbench-sched-devel.jpg

but there is still some peak regression left, i'm testing a patch for that.

There's one important bit missing from that graph, the 2.6.23-SCHED_BATCH values. Without that we can't tell how much improvement is from sched-devel and how much from SCHED_BATCH. Clearly 2.6.23 is better than 2.6.22.any in this test, the locking issues seem to dominate that difference to the point that nothing else would be informative.

This weekend I have to do some building of kernels for various machines, so I intend to run some builds SCHED_BATCH and some will just run. If I find anything interesting I'll report.

--
Bill Davidsen <davidsen@xxxxxxx>
"We have more to fear from the bungling of the incompetent than from
the machinations of the wicked." - from Slashdot

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