ULE Scheduler

[Oliver Fromme]

?????? ?????? <momchil at xaxo.eu> wrote:
 > I compiled the same kernel with the 4BSD scheduler today and it seems
 > that the processes jump accross cores too.

What exactly is the problem that you're seeing?  Do you have
performance problems?  If so, then they're probably *not*
caused by processes "jumping across cores".

Have you read Daniel Kalchev's reply in this thread?
He explained very well why that's not a problem usually.

Also note that top(1) only shows one snapshot every second
or two.  It does not show you the hundreds (or thousands)
of thread switches that happen every second.  In fact,
top(1) shows a very misleading picture because it creates
the wrong impression that your CPU-bound processes are
almost the only ones being scheduled on your cores.

Most of the time, people looking at top(1) see problems that
don't exist.  Another example is the amount of "free" memory
displayed by top that is often misinterpreted.

I suggest you just keep the standard scheduler (i.e. ULE).
If you don't have a performance problem (i.e. a problem that
you can measure by other means than top), then don't try to
fix it.  Chances are you make things worse.

Best regards
   Oliver


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