*BSD News Article 73943


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From: lm@neteng.engr.sgi.com (Larry McVoy)
Newsgroups: comp.os.linux.networking,comp.unix.bsd.netbsd.misc,comp.unix.bsd.freebsd.misc
Subject: Re: TCP latency
Followup-To: comp.os.linux.networking,comp.unix.bsd.netbsd.misc,comp.unix.bsd.freebsd.misc
Date: 16 Jul 1996 21:46:01 GMT
Organization: Silicon Graphics Inc., Mountain View, CA
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John S. Dyson (toor@dyson.iquest.net) wrote:
: Larry McVoy wrote:
: > Well, I doubt you'll buy it, but I agree with Linus that your message
: > certainly implied that Linux special cased the null syscal metric used
: > in lmbench.  IF that was your intended implication, you may not have been
: > lying, but you certainly were implying something that simply isn't true.
: >
: Firstly, you are one of the first people that I have seen who apparently
: understands that a lie requires intent.  Additionally, I was speaking of
: something inside of ME.  I did not do it.  

Cool, we're moving towards a conversation, rather than yelling at each other.
I like it.

Could you see, in rereading your posting, that perhaps people might have
seen implication that Linux had a special case for a null syscall?  I'll
grant you that it never helps to assume the worst, but I think a lot of 
objective observers would have read your posting the same way.  It could
have been an honest mistake, but why did you phrase it with the obvious
implication that Linux had cheated/optimized that case, whatever?  

I think Linus was a little justified in pointing out that it was simply
good coding, rather than a special case optimization, that made Linux 
fast.  I imagine he felt pretty insulted that you suggested he'd special
case to make Linux look better - for what it is worth, I would be amazed
if he did that, he's far too concerned with "doing the right thing" (as
are you, John, you guys are somewhat similar in that respect) to 
special case up his code.

I'll bet if I suggested that FreeBSD had special cases in it for benchmarking,
you would go ballistic.  And if it was in an area where you had worked hard
to solve the _general case_ and then I implied you had done some sleazy
hack for benchmarking purposes, you would scream foul even more
loudly.  

At any rate, I'm encouraged to see that we are all calming down a bit
and maybe we could move this topic onto something a bit more interesting,
like, say, the perfect loaded TCP latency benchmark?

As Alan has brought up, it isn't fair to just do a benchmark with one
client, because it doesn't stress the arp table enough.  Does everyone
buy that argument and what should be done about it?
--
---
Larry McVoy     lm@sgi.com     http://reality.sgi.com/lm     (415) 933-1804