Re: [PATCH 3/2] Avoid unnecessary strlen() calls

From: Junio C Hamano <junkio@cox.net>
Date: Mar 18, 2007, 09:45 UTC
Message-ID: <7v8xdunavr.fsf@assigned-by-dhcp.cox.net>
In-Reply-To: <Pine.LNX.4.64.0703171949190.6730@woody.linux-foundation.org>

Linus Torvalds <torvalds@linux-foundation.org> writes:

> This shaves off another ~5-10% from some loads that are very tree 
> intensive (notably doing commit filtering by a pathspec).
>
> Signed-off-by: Linus Torvalds  <torvalds@linux-foundation.org>"

With your 256-entry cache, Nico's reusing objects out of delta base cache, and this strlen() patch

	git blame -C block/ll_rw_blk.c

gets these numbers:

(v1.5.0) 14.71user 0.26system 0:15.07elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (0major+93622minor)pagefaults 0swaps

(master + three patches) 8.94user 0.14system 0:09.10elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (0major+40075minor)pagefaults 0swaps

Just for fun, these are the same for the kernel history with tglx-history repository's history grafted behind it, i.e. with this grafts file:

$ cat .git/info/grafts 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 e7e173af42dbf37b1d946f9ee00219cb3b2bea6a

(v1.5.0) 73.80user 2.57system 1:16.40elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (0major+773077minor)pagefaults 0swaps

(master + three patches) 65.14user 0.40system 1:05.55elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (0major+125052minor)pagefaults 0swaps

In either case, it is showing drastic reduction of minor faults.