Subject: Re: Bad response...
To: NetBSD-current Discussion List <current-users@NetBSD.ORG>
From: Greg A. Woods <>
List: current-users
Date: 09/01/2004 16:44:49
[ On Tuesday, August 31, 2004 at 23:17:03 (+0900), Noriyuki Soda wrote: ]
> Subject: Re: Bad response... 
>   If the unnecessary page-in happened at exec pages, increasing
>   vm.execmax may help, too.

Don't you mean "increasing vm.execmin"?  Increasing the max will only
help if exec pages are the primary user of memory (though it's default
is indeed a bit low at 30%, at least that would be low for any machine
that's really starved of physical memory if large programs are run on
it regularly).

However increasing the execmin will, IIUC, prevent exec pages from being
reclaimed when other uses demand memory and thus avoid having to page
them in again.

I think Arto Huusko's post yesterday (08/31) describes what I'm trying
to say much more clearly, and IIUC he's described things correctly.....

Indeed since this discussion started I've raised vm.execmin to 10% and
I've raised vm.execmax to 50% (on my 1.6.x server systems) and I have
noticed that my emacs sessions respond much more quickly now after
they've been left idle for a while.  I didn't have any major complaint
before, but things were more sluggish before than I had expected they
should be during compiles and cvs updates, etc.  Of course on my alpha
with 1.5GB of RAM, where I run mozilla, I've never had any real problem
with sluggish response of an idle application.  :-)

I also lowered vm.filemin to 5%.  10% of a large memory system is a lot
of memory to "waste" on the file cache IFF there are some other uses
that would better serve achieving maximum possible CPU utilisation....

I've been considering raising vm.execmin and vm.anonmin up to 25% each
though, or maybe even give anonmin 30% and execmin just 20% since that
seems to be a better balance for my normal daily usage.

Your discovery with Simon of the anonpages accounting weirdness in more
-current systems may also explain a lot of the complaints.  :-)

						Greg A. Woods

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