Re: [CFT][PATCH] new scheduler policy

Nick Piggin
2003-08-23T00:22:21Z

Roger Luethi wrote:

>On Fri, 22 Aug 2003 23:08:40 +1000, Nick Piggin wrote:
>
>>>I timed a pathological benchmark from hell I've been playing with lately.
>>>Three consecutive runs following a fresh boot. Time is in seconds:
>>>
>>>2.4.21 821 21 25
>>>2.6.0-test3-mm1 724 946 896
>>>2.6.0-test3-mm1-nick 905 987 997
>>>
>>>Runtime with ideal scheduling: < 2 seconds (we're thrashing).
>>>
>>>
>>Cool. Can you post the benchmark source please?
>>
>
>http://hellgate.ch/code/ploc/thrash.c
>
>A parallel kernel build can generate some decent thrashing, too, but I
>wanted a short and simple test case that conveniently provides the
>information I need for both logging daemon and post processing tool.
>
>Note: The benchmark could trivially be made more evil which would prevent
>2.4.21 from finishing over 30 times faster (as it often does). I
>intentionally left it they way it is.
>
>While everybody seems to be working on interactivity, I am currently
>looking at this corner case. This should be pretty much orthogonal to your
>own work.
>

Yes, improvements for this problem are usually in the form of a
secondary scheduler of sorts somewhere in the VM. Hard problem.