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Re: 100% CPU

From: Binley Lim <>
Date: Mon, 19 May 2003 20:51:48 -0800
Message-ID: <>

Not so clearcut. CPU 100% frequently is not good. Not going over 30% on average is bad.

If running at high CPU% and things run quickly and your users are happy, good. But if running at low CPU% , and users complain things run like a dog, bad.

Bottom line is - is your CPU doing useful work?

An example of expensive CPU (but not necessarily useful) work is NAS environments where extensive CPU is gobbled up to assemble/disassemble packets to/from the NFS server. If you manage to optimise this throughput to the NAS server, you can get very high CPU utilisation, and as well as very high throughtputs. High is good.

Over time, different hardware configurations will present different issues. So it depends....

> >Subject: Re: latch free - library cache
> >
> >So, what is spending the CPU? Why is a CPU running pedal to the medal a
> >problem?
> >I thought that CPU hardware was bought in order to run and not to sit
> >The same goes for the memory. There are some people, mostly known as sys

> Someone telling you that the cpu should be at zero percent is just being
> silly, however running at 100% is not an optimum condition. As one of the
> evil Sys Admins that you mentioned, I personally prefer my servers to not
> over 30% utilization on average, and prefer spikes to stay under 70%. If
> your hardware is running full bore all the time, two things will happen 1)
> Your hardware will wear out faster, especially hard drives, and 2) Your
> users will notice a slowed response time and complain. I'd say any server
> that runs over 50% usage on a regular basis is probably a good candidate
> either an upgrade or some load balancing

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Author: Binley Lim

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Received on Mon May 19 2003 - 23:51:48 CDT

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