Subject: Re: observations on a large-memory system.
To: Chuck Silvers <>
From: Thor Lancelot Simon <>
List: tech-kern
Date: 06/18/2001 16:57:21
On Mon, Jun 18, 2001 at 10:00:18AM -0700, Chuck Silvers wrote:
> On Fri, Jun 08, 2001 at 10:45:54AM -0400, Bill Sommerfeld wrote:
> > The following is with -current..
> > 
> > 1) ubc needs many vnodes to effectively use physmem for vnode page
> > cache.  For the NetBSD source tree, you need roughly 67000 vnodes to
> > cache roughly 670k of data.
> > 
> > A 2G system autoconfigures with roughly 40000 vnodes, where the above
> > ratio suggests that somewhere around 200000 vnodes might be a more
> > appropriate size.
> yes, we definitely need to adjust the tuning curves for various resources.
> I've been increasing the number of vnodes via /etc/sysctl.conf on my machines
> for a while now, but it would be nice to get more reasonable settings
> by default.

Has the memory consumption per vnode dropped with UBC, or are the vnode
structures themselves no longer in wired kernel memory?  200,000 vnodes
used to be entirely impractical because it consumed a massive amount of
wired KVA space.