From owner-freebsd-hackers  Thu Jun 24  9: 7:59 1999
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Date: Thu, 24 Jun 1999 12:18:16 -0400
From: Dan Moschuk <dan@trinsec.com>
To: hackers@freebsd.org
Subject: Beating system usage down
Message-ID: <19990624121816.A17448@trinsec.com>
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Greetings,

A machine that I hold very close under my wing has been very contently
chugging along for the last few months with practically no idle processor.
However, I noticed that the CPUs are spinning a lot of cycles in the
system area. 

CPU states:  5.5% user,  0.0% nice, 88.9% system,  4.0% interrupt,  1.6% idle

First, some background.

The machine is a Dual P2-450 with 1GB of RAM.  It runs apache, and currently
handles 90 hits a second, with each of those hits spawning various CGIs 
(one per hit) that completes in under a second.

My first theory was that the kernel was uselessly spinning in various record
locks via fcntl().  However, as a test I removed all file locking from the
various CGIs and noticed no change in the system usage.  My second theory
was the overhead with the SMP code.  So, I removed it from the kernel and
ran a single CPU box for a few minutes.  The system usage went down to 
around 60%, but the system was noticeably slower.

Any ideas?


Regards,

Dan


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