Re: git-index-pack really does suck..

On Tue, 3 Apr 2007, Shawn O. Pearce wrote:

Linus Torvalds [off-list ref] wrote:

quoted

On Tue, 3 Apr 2007, Shawn O. Pearce wrote:

quoted

If its the missing-object lookup that is expensive, maybe we should
try to optimize that.  We do it enough already in other parts of
the code...

Well, for all other cases it's really the "object found" case that is 
worth optimizing for, so I think optimizing for "no object" is actually 
wrong, unless it also speeds up (or at least doesn't make it worse) the 
"real" normal case.

Right.  But maybe we shouldn't be scanning for packfiles every
time we don't find a loose object.  Especially if the caller is in
a context where we actually *expect* to not find said object like
half of the time... say in git-add/update-index.  ;-)

First, I truly believe we should have a 64-bit pack index and fewer 
larger packs than many small packs.

Which leaves us with the actual pack index lookup.  At that point the 
cost of finding an existing object and finding that a given object 
doesn't exist is about the same thing, isn't it?

Optimizing that lookup is going to benefit both cases.


Nicolas