Subject: Re: bufpages
To: None <port-i386@NetBSD.ORG>
From: Greg Wohletz <greg@duke.CS.UNLV.EDU>
List: port-i386
Date: 06/29/1998 19:45:54
>>On Tue, 2 Jun 1998, Jukka Marin wrote:
>>
>>> I want to improve performance of a largish news server which has 80 MB
>>> of RAM.  According to options(4), I have to set options NBUF and/or
>>> BUFPAGES.  However, there is no information of the range of these
>>> constants - not even in the sample kerne config files.
>>> 
>> I'm building a NetBSD 1.3.2 kernel.  How should I set these constants?
>>
>>maxusers        200             # estimated number of users
>>options         NMBCLUSTERS=4096
>>options         BUFPAGES=4096   # 16MB for disk buffering
>>options         NBUF=4096
>
>What are the limitations for these paramters?  On one of our fileservers
>that has 32meg of ram, if I set BUFPGES/NBUF > 1024 it panics during
>autoconfig (pmap_pte returns null causing a ``ptdi'' panic in
>arch/i386/i386/pmap.c).  Is there a maximum ratio of BUFPAGES to real mem?
>

"Tom T. Thai" <tomthai@future.net> writes:
>Sorry, I have no idea about the limitations.. I did some calculations
>one, but forgot where my notes are.. :<  

Hmm.  Maybe someone else knows the answer.  BTW, is maxusers in anyway
related to some resource that pmap_pte uses?  I'm thinking it wouldn't be
but figured I'd ask...

I certainly would like to allocate a majority of the available RAM on my
fileservers to disk buffering, since all they do is run nfsd and that isn't
exactly a memory hog...

						--Greg