From: Mike Hommey <mh@glandium.org>
Date: Wed, 18 Jun 2008 09:05:27 GMT
Subject: Re: 'setup_work_tree()' considered harmful
Message-ID: <20080618090527.GA24254@glandium.org>
In-Reply-To: <alpine.LFD.1.10.0806161723081.2949@woody.linux-foundation.org>

On Mon, Jun 16, 2008 at 05:45:25PM -0700, Linus Torvalds wrote:
> ie note how it does one unnecessary "open()" less, but more importantly, 
> notice the difference between "/home/torvalds/kernel/.git/*" and ".git/*", 
> and realize that that second difference was the much more noticeable one.
> 
> And no, obviously the right fix is not to just comment out all of 
> "setup_work_tree()" (it will break stuff that depends on GIT_WORKTREE), 
> but I did that as a minimal example of showing what the bad effect of that 
> function is.
> 
> In general, I think we've gone in the wrong direction with a lot of the 
> "make_absolute_path" stuff. See above. 5% performance loss is not good.

Maybe using openat, fstatat, etc. when they are available, could be a
good thing, already, though it wouldn't help for other platforms.

Mike