Re: Set up for better tree diff optimizations

> On Wed, 21 Mar 2007, Junio C Hamano wrote:
> ...
>> Would something like this suit your taste?
>
> This looks fine, although the reason I didn't get it done myself is that I 
> have this nagging feeling that there must be some clever way to make it 
> even faster. I hated having to do the "strncmp()" early, when it's not 
> always needed. 
>
> But like your patch, I could never come up with a way to *both* do the 
> "don't strncmp() if you don't have to" *and* do the "nothing further will 
> be interesting any more" optimization..

>> The "rev-list org.eclipse.debug.ui/" test that took 16-17
>> seconds takes 9 seconds with this patch.  Running with a
>> diffrent pathspec "org.apache.ant/" obviously makes it go a lot
>> faster (15sec vs 7sec).
>
> Yeah, and conversely, a pathspec at the end of the list of paths will make 
> it less of an optimization. But in general it shouldn't ever be a loss 
> except for the rather rare case of asking for a path at the end of a tree, 
> and then the loss should be pretty small (ie it's the result of doing a 
> few strncmp's that we used to be able to skip).