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

Bill Hawes (whawes@star.net)
Fri, 27 Feb 1998 08:57:49 -0500


Dean Gaudet wrote:

> 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.

Hi Dean,

The case you cited may have dramatically overcommitted memory to disk buffers,
as the buffer hash lists could become very slow if there are too many buffers
allocated.

If you're interested in playing with this, I have a simple patch to limit buffer
allocations as a tunable parameter.

Regards,
Bill

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