On Fri, 18 May 2001, Stephen C. Tweedie wrote:
> On Fri, May 18, 2001 at 07:44:39PM -0300, Rik van Riel wrote:
>
> > This is the core of why we cannot (IMHO) have a discussion
> > of whether a patch introducing new VM tunables can go in:
> > there is no clear overview of exactly what would need to be
> > tunable and how it would help.
>
> It's worse than that. The workload on most typical systems is not
> static. The VM *must* be able to cope with dynamic workloads. You
> might twiddle all the knobs on your system to make your database run
> faster, but end up in such a situation that the next time a mail flood
> arrives for sendmail, the whole box locks up because the VM can no
> longer adapt.
That's another problem, indeed ;)
Ingo, Mike, please keep this in mind when designing
tunables or deciding which test you want to run today
in order to look how the VM is performing.
Basic rule for VM: once you start swapping, you cannot
win; All you can do is make sure no situation loses
really badly and most situations perform reasonably.
Rik
-- Virtual memory is like a game you can't win; However, without VM there's truly nothing to lose...http://www.surriel.com/ http://distro.conectiva.com/
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This archive was generated by hypermail 2b29 : Wed May 23 2001 - 21:00:31 EST