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From: Junio C Hamano <junkio@cox•net>
To: Linus Torvalds <torvalds@linux-foundation•org>
Cc: Geert Bosch <bosch@adacore•com>, Nicolas Pitre <nico@cam•org>,
	"Shawn O. Pearce" <spearce@spearce•org>,
	Dana How <danahow@gmail•com>,
	git@vger•kernel.org
Subject: Re: [RFC] Packing large repositories
Date: Sat, 31 Mar 2007 13:54:07 -0700	[thread overview]
Message-ID: <7vslbl8780.fsf@assigned-by-dhcp.cox.net> (raw)
In-Reply-To: <Pine.LNX.4.64.0703311033290.6730@woody.linux-foundation.org> (Linus Torvalds's message of "Sat, 31 Mar 2007 11:36:35 -0700 (PDT)")

Linus Torvalds <torvalds@linux-foundation•org> writes:

> In other words, the 256-entry fan-out was meant to avoid the first eight 
> levels of binary lookup. But the thing is, we should be able to generally 
> do a *lot* better than any binary lookup by just doing a LINEAR SEARCH, 
> which is also more cache-friendly, and prefetches much better when it's 
> not in the cache.
> ...
>  - use newton-raphson to iterate closer. It should be a much faster way to 
>    find the rough area for the entry we're searching for than binary 
>    search. Two or three iterations should get us there, easily.

This is another egg of columbus moment that makes me feel it was
worth to have been in git community ;-).

I like it.

  parent reply	other threads:[~2007-03-31 20:54 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-03-28  7:05 [RFC] Packing large repositories Dana How
2007-03-28 16:53 ` Linus Torvalds
2007-03-30  6:23   ` Shawn O. Pearce
2007-03-30 13:01     ` Nicolas Pitre
2007-03-31 11:04       ` Geert Bosch
2007-03-31 18:36         ` Linus Torvalds
2007-03-31 19:02           ` Nicolas Pitre
2007-03-31 20:54           ` Junio C Hamano [this message]
2007-03-31 21:20           ` Linus Torvalds
2007-03-31 21:56             ` Linus Torvalds
2007-04-02  6:22           ` Geert Bosch
2007-04-03  5:39             ` Shawn O. Pearce
2007-03-31 18:51         ` Nicolas Pitre
2007-04-02 21:19   ` Dana How
2007-04-02  1:39 ` Sam Vilain

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