Subject: ftpd CPU usage increases when idle

From: "Carl D. Cravens" <[email-masked]>
Date: Tue, 17 Dec 1996 16:11:53 -0600 (CST)

We've recently noticed a problem with significant system load and have
tracked it down to periods when there are several incoming ftp
connections.  Watching the behavior of ftpd, we've discovered that the
process takes up the *most* CPU time when it's *idle*.  One would expect
an program waiting on input for further instructions to take up zero CPU
time until an interrupt signaling incoming data or a timeout wakes it up.
Is wu-ftpd sitting in a wait-loop here?

If anyone can help me with this (preferably patches or configuration
instructions that fix it) I'd really appreciate it. 

--
Carl D. Cravens                  Technical Support / Junior Administrator
[email-masked]            <Troll-in-Training>
SouthWind Internet Access, Inc.  Wichita: 316-263-7963
http://www.southwind.net/        Elsewhere: 1-800-525-7963

---

From: "Carl D. Cravens" <[email-masked]>
Date: Tue, 17 Dec 1996 16:33:37 -0600 (CST)

> process takes up the *most* CPU time when it's *idle*.  One would expect

Excuse me, but I should clarify that...  *sometimes* its CPU usage jumps
way up.  Most of the time it's insignificant, but when the system load
spikes, we can be sure to find three or four high-CPU-but-idle ftpd's in
the top 20 processes.  When they go non-idle, their CPU usage drops back
down.