Subject: Re: UVM/other problems for desktop users in current?
To: George Michaelson <ggm@apnic.net>
From: Daniel Carosone <dan@geek.com.au>
List: current-users
Date: 12/18/2002 16:57:30
On Wed, Dec 18, 2002 at 03:05:35PM +1000, George Michaelson wrote:
> > For those experiencing this problem - are you running softdep?
> Yes

Hm, ok.  Another suggestion below.
 
> > FreeBSD is probably using softdep by default (?), Linux is effectively
> > mounting async. Do the same on NetBSD, and then compare again.
> 
> Hmm. I think async comes with markedly more risks doesn't it? At least thats
> how I've read the complaints about Linux FS practices vs BSD. Are you *sure*
> this is a good idea?

I think it's a terrible idea :)

I was suggesting you run softdep (if not already), not async!
The point was simply that without softdep, you're making unfair
comparisons.

*With* softdep, you have a better chance of effective change by
twiddling uvm/ubc knobs, as it's probably a matter of tuning memory
usage to requirements. 

One other thing I do on my laptop that helps both compiles and cvs:
kern.maxvnodes=65536

I did this because I was struggling to use all of my RAM, even for file
cache, as i'd run out of vnode handles first.  You may not have
this problem, but it's another knob to try - and indeed I have the
vm.*{min,max} at defaults.

> > Other things to help further:
> >
> >   - [noatime]
> 
> I'm going to try this next.
> 
> >   - [NEW_BUFQ_STRATEGY]
> 
> I'm going to try list last! :-)

heh :)

--
Dan.