Subject: Re: tuning for small memory machines
To: Simon Burge <simonb@wasabisystems.com>
From: Brian Chase <vaxzilla@jarai.org>
List: tech-kern
Date: 11/29/2002 13:28:42
On Wed, 27 Nov 2002, Simon Burge wrote:
> I'm running with vm.anonmax=95 now.
>
> Now, the question is should we automatically tune vm.anonmax up high
> for low-memory situations? And what would qualify as a "low-memory"
> situation?
FWIW, out of curiosity, I decided to tweak the vm.anonmax value on my
16MB MicroVAX 3100 (avail memory 12212KB) running the 1.6 release.
I was hoping this might improve my compilation performance a bit.
For my test, I compiled two identical kernels. I used the `time'
command to time the compiles.
With the default vm.anonmax=80, the `make netbsd' time is as follows:
16479.544u 996.689s 4:59:27.65 97.2% 0+0k 141+9374io 754pf+76w
And by setting vm.anonmax=95, the `make netbsd' time is:
16487.698u 991.133s 4:59:23.60 97.3% 0+0k 154+9285io 723pf+78w
I was astonished with how close the results were, and obviously a bit
disappointed to not see any gains. Maybe there are none to be had
with my whopping 12MB of available memory? :-)
-brian.