Subject: Re: FreeBSD Bus DMA
To: None <>
From: Jason Thorpe <>
List: tech-kern
Date: 06/11/1998 22:21:22
On Thu, 11 Jun 1998 23:45:35 -0400 
 "Perry E. Metzger" <> wrote:

 > I don't care much about the VAX. What I care about is next year's
 > system that requires flexibility in ways that having the VAX work
 > taught us to accomodate. As it stands, we work on virtually everything 
 > that can be thrown about us -- and these days, building a new port is
 > becoming a cookie cutter operation, with massive code sharing.

Running on insanely slow hardware also motivates you to improve the
performance of your kernel :-)

I recall that Ragge (the VAX port gooroo) posted that his uVAX-II ran
/etc/rc something like 10 or 15 seconds faster w/ UVM :-)

Also, I recall that the Arm32 guys, Mark and Neil (who John indirectly
referred to earlier, in case you didn't know) observed quite a noticeable
performance boost w/ UVM, and after making some changes to their pmap
suggested by Chris Demetriou and Chuck Cranor (IIRC - I was put in the loop
on the mail exchange, and I'm pretty sure he posted to port-arm32 about it),
got additional performance gains near the _50%_ range!

Can't wait to run that code on my Shark :-)

Jason R. Thorpe                             
NASA Ames Research Center                            Home: +1 408 866 1912
NAS: M/S 258-5                                       Work: +1 650 604 0935
Moffett Field, CA 94035                             Pager: +1 650 428 6939