Subject: Re: FreeBSD Bus DMA
To: Ted Lemon <>
From: John S. Dyson <>
List: tech-kern
Date: 06/11/1998 22:41:59
Ted Lemon said:
> > > So you're willing to make claims about FreeBSD's performance, but
> > > you're not willing to back them up with numbers?   Am I the only
> > > person to whom this seems more than a little bit disingenuous?
> > > 
> > If I don't do all your work for you to improve your OS, it isn't
> > my fault. You should take it as a challenge to improve the results
> > of your project, just as I do mine.
> John, you're saying that NetBSD performs in an inferior manner to
> FreeBSD.   I haven't seen any evidence of that.   This is not
> something that I'm hearing from other people.   I suspect that it's a
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  Then listen.
> prejudice, and not a fact.   This is why I'm asking you about
> benchmarks.   If you haven't run benchmarks, how do you know?   The
                ^^^^^^^^^^^^^^^^^^ That is of course untrue.
> answer is that you don't.   That is what I am trying to point out.
Your evaluation of the situation is faulty.  You can work to improve
things or not.  It is your project.

> I'm talking about the complete rewrite of NetBSD's VM code, which
> happens to correct the problem that you were talking about when you
> brought up NetBSD's poor performance under paging at the FreeBSD BOF
> in New Orleans (or was it San Diego?).
The code is NOT a complete rewrite.  Please refer to it.  Asserting
that it is, could be a lie, but maybe only poorly informed.

> > I chose to fix the VM code, by making it work as advertised, and
> > you guys ended up rewriting alot of it from scratch.  So what?
> I don't know so what.   That's what I'm asking you.
Well, you were the one talking about a bugfix.  If you think that
paging or object inheritance are the only issues, you are very sadly

You are falling into the fallacy of lying, or at least showing
that you arent very well informed :-).  Please refer to the VM code
copyrights.  In fact, for fun, take a look at the vm_map replacement
file, and tell me that the VM code is a rewrite :-).

John                  | Never try to teach a pig to sing,     | it just makes you look stupid,         | and it irritates the pig.