Yes, Ted did it, earlier this year.
> BTW, I assume the ext2 dir index patch is roughly equivalent to FreeBSD
> dirhash and the the other patch resembles theFreeBSD dirperf patch?
> Have you looked at them? [http://www.osnews.com/story.php?news_id=153]
I *think* the performance of my dir index patch is roughly in line with BSD's
dirhash patch, for common cases. The big difference is that the BSD dirhash
is not persistent - the cache goes away when the directory is closed. So
there are loads that can break it badly, such as accessing files in large
directories randomly over a large disk. This forces the entire directory to
be read into cache, in the worst case, on every access. Another bad case is
first-time access. A million file directory is around 30 meg - it takes a
long time to read and hash all those blocks, just to open the first file.
They will have to implement a persistent index at some point. For common
cases though, the BSD approach is good.
I'll go into the gory details next week at ALS if people are insterested.
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