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Date:      17 Jul 2006 11:07:10 +0200
From:      Andreas Hauser <andy@splashground.de>
To:        Brooks Davis <brooks@one-eyed-alien.net>
Cc:        freebsd-performance@freebsd.org, User Freebsd <freebsd@hub.org>
Subject:   Re: Is 6.x slower then 4.x ... ?
Message-ID:  <20060717090710.22834.qmail@shadow.splashground.de>
In-Reply-To: <20060717030249.GB3344@lor.one-eyed-alien.net>
References:  <20060716114546.B1799@ganymede.hub.org> <20060717030249.GB3344@lor.one-eyed-alien.net>

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brooks wrote @ Sun, 16 Jul 2006 22:02:50 -0500:
> On Sun, Jul 16, 2006 at 11:49:35AM -0300, User Freebsd wrote:

> FreeBSD 6 is slower than 4 for some things and faster for others.  That
> should be expected since fine grained locking involves increased numbers
> of expensive atomic operations (which are particularly bad on Intel
> P4 and Xeon systems).  The gain is that we've got significantly more
> parallelism in many areas (for example, see kris's I/O benchmarking
> presented at BSDCan).  Looking at it as a thought experiment, you should
> expect microbenchmarks to perform worse, sometimes much worse.  If
> your application looks like those microbenchmarks that's going to be a
> problem, if not it may or may not be.

OK. Kris presented exactly one benchmark were 6 is better (30%) and that
is with sync mounts. Sorry, but i don't know many people running async
mounts.

Since none of the benchmarks from people seem to have influence on you,
why not provide benchmarks, application ones, that show that 6 is good
in anything performance wise. Until then we keep thinking it is worse,
since our benchmarking shows it to be worse (of course we are doing it
all wrong ...).

> In short the black and white question you are asking makes little
> sense. :)

It usually boils down to a black and white question like
"Use or do not use?".

-- 
Andy



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