From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Wed, 18 Feb 2009 22:44:34 GMT
Subject: Re: [PATCH] check_updates(): effective removal of cache entries marked CE_REMOVE
Message-ID: <alpine.LFD.2.00.0902181436390.21686@localhost.localdomain>
In-Reply-To: <1234995483-933-1-git-send-email-barvik@broadpark.no>



On Wed, 18 Feb 2009, Kjetil Barvik wrote:
> 
> To fix this, and use an O(N) algorithm instead, where N is the number
> of cache_entries, we delete/remove all entries in one loop through all
> entries.

Ack. We've had things like this before. I'm somewhat surprised that it is 
noticeable even in the "o->update" case (since I would have expected the 
cost of actually doing an unlink() to swamp the memmove overhead), but the 
patch looks obviously correct. 

Looking at the numbers, I guess it's not _really_ noticeable - it's 1.8% 
of git user-space time, which in turn is about 75% of total time, so it's 
not a huge improvement, but I'll certainly ack it anyway as being the 
right thing to do. Every little bit helps. 

			Linus