Make zlib compression level configurable, and change default.

With the change in default, "git add ." on kernel dir is about
twice as fast as before, with only minimal (0.5%) change in
object size. The speed difference is even more noticeable
when committing large files, which is now up to 8 times faster.

The configurability is through setting core.compression = [-1..9]
which maps to the zlib constants; -1 is the default, 0 is no
compression, and 1..9 are various speed/size tradeoffs, 9
being slowest.

Signed-off-by: Joachim B Haga (cjhaga@fys.uio.no)
Acked-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

1 files changed, 1 insertions, 1 deletions

diff --git a/diff.c b/diff.c
index 5a71489a4..428ff786e 100644
--- a/diff.c
+++ b/diff.c
@@ -583,7 +583,7 @@ static unsigned char *deflate_it(char *data,
 	z_stream stream;
 
 	memset(&stream, 0, sizeof(stream));
-	deflateInit(&stream, Z_BEST_COMPRESSION);
+	deflateInit(&stream, zlib_compression_level);
 	bound = deflateBound(&stream, size);
 	deflated = xmalloc(bound);
 	stream.next_out = deflated;