Re: A request to those people who want B-tree directories

Dean Gaudet (
Fri, 27 Feb 1998 00:56:46 -0800 (PST)

On Fri, 27 Feb 1998, Theodore Y. Ts'o wrote:

> Another way of asking the question is --- of those people who complain
> that it takes too long to look up a filename in a directory: while Linux
> is looking up a filename in a large directory, is Linux disk bound or
> CPU bound? If Linux is being disk bound, there are much better
> solutions that don't necessarily require a B-tree.

CPU bound. My reason for this hypothesis:

- take a box w/512Mb of RAM, 2.1.62+, and run innd on it

- watch the control newsgroup directory grow and grow

- watch the system become so sluggish it feels like you're typing behind a
1000ms latency link

- strace innd and watch open()s in the control directory take over 1s...
which happen to be about the length of the lag you feel while typing

No joke, the system had over 350Mb cached, it was definately not touching
disk while accessing this directory. If it were touching disk I bet
interactive performance would have been better.


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to