Subject: CPU-bound application performance degradation
To: None <firstname.lastname@example.org>
From: Erik E. Fair <email@example.com>
Date: 04/27/2001 02:19:05
One of the things I do on most of my systems is run the
distributed.net RC5-64 key cracker, at nice +20, to soak up the space
Some months ago, they released a new version of the client for
NetBSD/alpha, and the performance on my 500 MHz PC164 and 500 MHz
DigitalServer 3305 (nee AlphaServer 800) doubled from 400
kilokeys/sec to 800+ kilokeys/sec. Some clever person had obviously
spent time optimizing the inner loop. Bravo for a factor of two.
However, I notice that when running the client, after some number of
hours and key block iterations, performance of the client halves back
down to 400 Kkeys/sec, and stays there. This happens on both 1.4.3
and 1.5.1_ALPHA, with identical client code.
If I kill and restart the client, it delivers the 800 Kkeys/sec
performance again, for a while...
Now, assuming that the distributed.net people haven't done anything
wierd in the code and that the client is doing its best to run flat
out with no waiting, what could NetBSD be doing that causes this