Re: 2.6.0-test2-mm3 osdl-aim-7 regression

From: Nick Piggin (piggin@cyberone.com.au)
Date: Thu Aug 07 2003 - 00:11:52 EST


Con Kolivas wrote:

>On Thu, 7 Aug 2003 05:10, Cliff White wrote:
>
>>>Binary searching (insert gratuitous rant about benchmarks that take more
>>>than two minutes to complete) reveals that the slowdown is due to
>>>sched-2.6.0-test2-mm2-A3.
>>>
>
>This is most likely the round robinning of tasks every 25ms. The extra
>overhead of nanosecond timing I doubt could make that size difference (but I
>could be wrong). There is some tweaking of this round robinning in my code
>which may help this, but it won't bring it back up to original performance I
>believe. Two things to try are add my patches up to O12.3int first to see how
>much (if at all!) it helps, and change TIMESLICE_GRANULARITY in sched.c to
>(MAX_TIMESLICE) which basically disables it completely. If there is still a
>drop in performance with this, the remainder is the extra locking/overhead in
>nanosecond timing.
>
>
What is the need for this round robining? Don't processes get a calculated
timeslice anyway?

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