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Date:      Tue, 14 Nov 2006 16:59:48 +0100
From:      Andre Oppermann <andre@freebsd.org>
To:        Poul-Henning Kamp <phk@phk.freebsd.dk>
Cc:        arch@freebsd.org
Subject:   Re: a proposed callout API
Message-ID:  <4559E7F4.4000603@freebsd.org>
In-Reply-To: <11832.1163519171@critter.freebsd.dk>
References:  <11832.1163519171@critter.freebsd.dk>

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Poul-Henning Kamp wrote:
> In message <4559E301.2030607@freebsd.org>, Andre Oppermann writes:
>> Luigi Rizzo wrote:
>>> On Tue, Nov 14, 2006 at 04:11:20PM +0100, Andre Oppermann wrote:
>>> ...
>>>> It's important to know that any random memory accesses on modern
>>>> CPUs are really expensive because of cache misses.  That's why
>>>> Judy tries beat RB tries by an order of a magnitude these days.
>>> you mean this stuff ?
>>>
>>> http://docs.hp.com/en/B6841-90001/ch02s01.html
>>> http://judy.sourceforge.net/
>> We've used it a number of other projects and it beats everything
>> else hands down in speed and memory consumption.
> 
> I would like to thank you all for your enthusiasm in promoting
> various data structures, but I kindly remind you that the only
> sorting requirement we have for the short/likely callouts is
> to know which one is next and that we may have duplicate keys.

Heh.  I never meant to propose any particular data structure for
the callout stuff.  Judy and RB were purely meant to illustrate
the (non-)cache busting effect.  I certainly wouldn't want to
include Judy in the kernel.

-- 
Andre




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