Re: performance problem: "git commit filename"

On Sat, 2008-01-12 at 20:04 -0800, Linus Torvalds wrote:

It makes builtin-commit.c use the same logic that "git read-tree -i -m" 
does (which is what the old shell script did), and it seems to pass the 
test-suite, and it looks pretty obvious.

It also brings down the number of open/mmap/munmap/close calls to where it 
should be, although it still does *way* too many "lstat()" operations (ie 
it does 4*lstat for each file in the index - one more than the 
non-filename one does).

With that fixed, performance is also roughly where it should be (ie the 
17-18s for the cold-cache case), because it no longer needs to rehash all 
the files!

HOWEVER. This was just a quick hack, and while it all looks sane, this is 
some damn core code. Somebody else should double- and triple-check this.

I took a look too, and it looks to me like the it's the exact same code
path in builtin-read-tree.c that the old

        git read-tree --index-output="$TMP_INDEX" -i -m HEAD

part of the shell script would trigger.  So yes, this look like the
right fix to me.

Signed-off-by: Kristian Høgsberg <redacted>