> Shawn Leas wrote:
> Yeah, I thought btrees in the FS would be simple until we tried it. I mean,
> how complicated could it get....? We are still finding factor of two write
> speedups with 4 line tuning changes.....
> Now we are tuning reads.....
Hehehe, I have faith that you will find optimal solutions, as I see you as
one who understands fully the scale of what you attempt.
> It can be worth remembering that no matter what you do, readdir on a large
> directory will be slow, and a lot of utilities assume readdir is fast. I
> think that if you user reiserfs for a million node directory it won't be
> reiserfs that will collapse in performance, it will be things like the shell
> and find.
Yes, certain *reasonable* assumptions are made when writing these
utilities. Understood.
> With respect to your test, I assume you understand that if you had used a 1
> million entry directory, it would be a more than 30 to 1 speedup. Also, you
I understand.
> should be aware that "find" not reiserfs is probably the bottleneck in your
> test. I haven't really done good tests of how fast reiserfs is for really
> large directories. I would have to carefully select the test so that it
> wasn't the utility that was breaking under the impact of a 1 million entry
> directory. I seem to have some memory last year of running benchmarks based
Also agreed. Maybe when reiserfs gets 1.0, you can modify versions of
findutils for optimal use with reiserfs??? Selling the idea to comercial
land would then be even more tasty.
> on find /testfs -name 'some_pattern' -exec some_fs_altering_action {} \; on
> just a little 16k entry directory and seeing find consume most of the CPU as
> user not kernel CPU. Oh well. I think I would need to write a c program to
> benchmark reiserfs for large directories, and at the time I was trying to
> write benchmarks that were simple enough to be precisely described in a paper
> in a few lines at the time. Besides, why go into gory detail showing that
> ext2fs can't handle large directories well was my thought. It wasn't
> designed to do that, so it isn't fair to complain about it. Better that I
> spend my time getting reiserfs ready to ship.....
I gawtta say, you are another of my favorite developers. A
revolutionary...
-Shawn
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