Re: [PATCH 11/11] Improve merge performance by avoiding in-index merges.

[Shawn Pearce <spearce@spearce.org>]

Junio C Hamano <junkio@cox.net> wrote:
> "Shawn O. Pearce" <spearce@spearce.org> writes:
> 
> > For a really trivial merge which can be handled entirely by
> > `read-tree -m -u`, skipping the read-tree and just going directly
> > into merge-recursive saves on average 50 ms on my PowerPC G4 system.
> > May sound odd, but it does appear to be true.
> 
> This sounds awfully attractive yet disruptive.  Should be cooked
> in 'next' for at least two weeks, maybe even longer to verify
> that performance figure holds for everybody.

I agree.  I have been thinking about doing this for a while but
just never sat down and did it until night.  To get it in 1.5.0 I
probably should have done this back in early Decmember.  Whoops,
bad timing on my part.  ;-)
 
> Also I think you need to make sure running merge-recursive
> upfront offers the same safety as the code you are removing then
> running it, as I vaguely recall its checking for local changes
> were slightly looser.

>From what I can tell, merge-recursive and read-tree -m are running
exactly the same code.  So aside from the fact that I bypassed the
update-index --refresh by accident, I don't think they will have
different outcomes.

-- 
Shawn.