On Sun, 18 Mar 2007, Junio C Hamano wrote: > > git blame -C block/ll_rw_blk.c > > 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. That's an interesting test-case (and I get 53 seconds, nyaah, nyaah ;) However, it's almost totally *not* about object access any more with my patches. All the top profiling hits are about generating the patches and assigning blame: samples % image name app name symbol name 470352 15.5813 git git xdl_hash_record 298683 9.8944 git git cmp_suspect 225156 7.4587 git git assign_blame 221308 7.3312 libc-2.5.so libc-2.5.so memcpy 177621 5.8840 libc-2.5.so libc-2.5.so memchr 163571 5.4186 vmlinux vmlinux __copy_user_nocache 129301 4.2833 git git xdl_prepare_ctx 99009 3.2799 libc-2.5.so libc-2.5.so _int_malloc 83899 2.7793 git git xdiff_outf 80588 2.6696 libz.so.1.2.3 libz.so.1.2.3 (no symbols) .. so as you can see, libz is down in the 2.5% range, and strlen and the tree accessor functions are totally un the noise. So it looks like it *used* to be somewhat of a problem (the object access itself must have been about 10 seconds, since that got shaved off the time), but realistically, if you want to speed up "git blame", we can totally ignore the git object data structures, an dconcentrate on xdiff and on blame itself (cmp_suspect and assign_blame probably have some nasty O(n^2) behaviour or something like that, that could hopefully be fixed fairly easily. The xdl hashing is a different thing, and I don't think it's necessarily easy to fix that one..) Linus - To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html