Subject: Re: maxusers and its progeny
To: David Paul Zimmerman <dpz@apple.com>
From: None <Chris_G_Demetriou@NIAGARA.NECTAR.CS.CMU.EDU>
List: port-alpha
Date: 01/03/1996 10:59:57
> The really odd thing is that things work fine with a small maxusers 
> setting (16), so I think I'm simply blowing some array along the way that 
> a maxusers-derived variable uses.  I've tracked this problem to begin at 
> a fairly low maxusers, like 32 to 48.  So the question: am I chasing 
> around a known issue, or is this a new thing?  My system config is an 
> AlphaStation 250 4/266 with 128MB of memory, 1GB sd0, 2GB sd1, console on 
> ttyC0; config file attached.

Actually, the biggest problem is that upping max-users (given the way
various things in the pmap works) causes a _GIGANTIC_ amount of kernel
virtual space to be used...

as i recall (i looked at it a while ago), it increases linearly with
maxusers, and with maxusers == 16 it's ~1G and maxusers == 32 it's
~2G.  (something like that; i know that i was running into 'int'
signedness problems, and i think it was while trying maxusers == 32.)

the kernel only allows 8G of KV-space, max, and i've not tried to boot
with anything larger than '32'.  as i recall, '32' worked, though.



chris