[Ocfs2-devel] Another ocfs2 performance bug

[Zach Brown]

> Reading all the files in a big directory tree takes at least four times
> as long on ocfs2 as ext3.

> real   1m54.933s  <===

> real    0m23.899s <===

Can you doctor your scripts to show at least some overview of the IO
patterns?  Just the amount of reads and writes would be a good start,
but something like graphing blktrace output would be wildly instructive.

My first guess would be the known difference between OCFS2's full-block
inodes and ext3's habit of packing lots of inode structs into a block.

Secondary guesses would be lack of directory read-ahead, bad IO patterns
based on allocation policy, etc..

- z