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Date:      Sat, 29 Sep 2007 18:45:20 +0200
From:      Kris Kennaway <kris@FreeBSD.org>
To:        freebsd-questions@freebsd.org
Subject:   Re: Questions on the scheduler
Message-ID:  <46FE8120.4040608@FreeBSD.org>
In-Reply-To: <20070929163116.GA1748@olymp.home>
References:  <80f4f2b20709240723m121aad88ofaf728f384dd6c20@mail.gmail.com>	<20070924184415.7bffd7d2@gumby.homeunix.com.>	<46FE790A.1000101@FreeBSD.org> <20070929163116.GA1748@olymp.home>

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Oliver Herold wrote:
> Are there any numbers or technical papers? Just out of curiosity.

I ran a mysql benchmark against Dragonfly-current and FreeBSD 7 on an 
8-core machine (one of the workloads that FreeBSD now performs very well 
at) and found 0 scaling on dragonfly.  Their developers confirmed that 
the kernel is still entirely giant locked (as in FreeBSD 4) so no SMP 
performance benefits are possible.

The email thread is here:

   http://leaf.dragonflybsd.org/mailarchive/users/2007-05/msg00134.html

although the linked graph is offline.  The FreeBSD curve was essentially 
this one (FreeBSD has improved further since then):

   http://people.freebsd.org/~kris/scaling/scaling.png

with dragonfly a flat line at ~500 tps independent of load.

Kris




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