Messages in this thread | | | Date | Sun, 18 May 2003 16:57:18 -0600 | From | Andreas Dilger <> | Subject | Re: [Ext2-devel] [RFC] fast EA for ext3 |
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On May 18, 2003 17:04 +0000, Alex Tomas wrote: > this patch implements possibility to store EA into inode body > which may be larger 128 bytes in 2.5 kernel.
What Alex didn't mention was the reason why we developed this patch in the first place - speed. Storing EAs in external blocks is slow, and if you have a lot of inodes with external EAs it is fatal, as the EA blocks consume so much RAM that they force all of the inode/directory data out of cache.
Some benchmarks (from Alex): > environment for old EA: just mkfs'ed EXT3, inode size 128, 33000 files > environment for fast EA: just mkfs'ed EXT3, inode size 256, 33000 files > > old EA fast EA > add attributes 2m35.241s 1m4.151s (+142%) > dump attributes 0m28.716s 0m13.466s (+113%) > change attributes 2m42.108s 1m4.413s (+153%) > remove attributes 1m15.373s 1m3.909s (+19%)
Some minor improvements could be made, such as not storing user EAs inside the inode if there are system EAs that could be stored there.
Cheers, Andreas -- Andreas Dilger http://sourceforge.net/projects/ext2resize/ http://www-mddsp.enel.ucalgary.ca/People/adilger/
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