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Message-ID: <4CFFF394.1020303@redhat.com> Date: Wed, 08 Dec 2010 15:07:32 -0600 From: Eric Sandeen <sandeen@...hat.com> To: Andreas Dilger <adilger.kernel@...ger.ca> CC: Andrew Morton <akpm@...ux-foundation.org>, ext4 development <linux-ext4@...r.kernel.org>, Jan Kara <jack@...e.cz> Subject: Re: [PATCH 1/2] ext2: speed up file creates by optimizing rec_len functions On 12/08/2010 01:01 PM, Andreas Dilger wrote: > On 2010-12-07, at 14:33, Andrew Morton wrote: >> On Tue, 07 Dec 2010 15:22:55 -0600 Eric Sandeen >> <sandeen@...hat.com> wrote: >>> Retesting at a bunch of different number-of-files in bonnie (with >>> a small sample size so probably a little noise) >>> >>> |files per sec| files stock patched delta 10,000 12300 14700 >>> +19% 20,000 6300 7600 +20% 30,000 4200 5000 +20% 40,000 3150 >>> 3700 +17% 50,000 2500 3000 +20% >>> >>> (again all on a 512MB ramdisk) >>> >>> *shrug* I'll believe my lyin' eyes, I guess. :) >> >> I bet other tweaks in there would yield similar goodliness. > > 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. -Eric > In the past, ext3_mark_inode_dirty() was a major offender, and I > recall that we discussed on the ext4 concall a mechanism to only copy > the inode once per transaction so that overhead could be removed. > > Cheers, Andreas > > > > > -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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