Messages in this thread | | | Date | Sat, 19 May 2001 08:45:57 +0200 (CEST) | From | Mike Galbraith <> | Subject | Re: Linux 2.4.4-ac10 |
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On Fri, 18 May 2001, Rik van Riel wrote:
> 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.
I've bent your code up a bit. I've not yet been tempted to replace any of it with a knob ;-) There is a little piece I'd like to see thrown away though.. the loop in refill_inactive does nothing good.
The test I prefer is a good one for the area of vm performance I'm most interested in. It doesn't cover the full vm spectrum by any means. I don't have a setup (any) good for testing mondo network or IO stuff. I test a simple 'job one size to large' scenario. Yes, it's limited test coverage.. it's still legitimate.
Perhaps when you're evaluating vm performance, you should try my simple test once in a while. :) I'll bet you a bogobeer right here and now that when 2.4.5 hits the street you're going to be queried by the big-busy-box folks wrt swap volume.
> 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.
I disagree with that. I've seen a heavily swapping box run like a scaulded ass ape many times.
Warsteiner,
-Mike
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