On 2010-12-08, at 14:07, Eric Sandeen wrote: > On 12/08/2010 01:01 PM, Andreas Dilger wrote: >> I think an important factor here is that this is being tested on a >> ramdisk, and is likely CPU bound, so any CPU reduction will directly >> be measured as a performance improvement. Probably oprofile is in >> order to see where other major CPU users are. > > Yep, I ran oprofile. > > samples % app name symbol name > 1140046 41.8702 ext2.ko ext2_find_entry > 1052117 38.6408 ext2.ko ext2_add_link > 98424 3.6148 vmlinux native_safe_halt > 40461 1.4860 vmlinux wait_on_page_read > 29084 1.0682 vmlinux find_get_page > > pretty slammed on those 2 ext2 functions! I think it's pretty > overwhelmed by the linear search. Can you test ext4 with nojournal mode, but with dir_index enabled? I suspect that testing ext2 for directory performance is pointless. My personal threshold for ext2 directories was 10k files before I considered it a lost cause, and all of your tests are with 10k+ files per directory. Just another log on the fire beneath getting rid of ext2 (and eventually ext3) in favour of ext4, IMHO. I'd be surprised if there are many benchmarks that ext2 can beat ext4 in nojournal mode, if allowed to enable "reversible" format changes like dir_index, uninit_bg, etc. Cheers, Andreas -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
