Re: Compaq 350MHz PII + Linux performance degradation of 500% after

Aaron Lehmann (aaronl@vitelus.com)
Wed, 14 Apr 1999 03:09:35 +0000 ( )


I also saw this on a 450MHz Compaq PII. The problem was that power
management was turned on in the BIOS and was slowing it down to the speed
of a 486 after a few hours of operation. Turn power saving features off in
the BIOS. Yet another reason to avoid proprietary hardware.

On Tue, 13 Apr 1999, Rolf Fokkens wrote:

> If have two Compaq 350MHz PII machines. They both show a drastic
> performance degradation after running a while. This performance
> degradation vanishes after a reboot. These are the circumstances when
> the performance is bad:
> * About 60 processes with a load of 0.1 or less
> * More than 64 MB memory (one has 128MB, the other has 192MB)
> * No swap space used
> * Almost all memory used; (mostly for buffering, about 50MB is needed
> for the processes)
> * The performance degradation seems to be purely CPU related (mpg123
> decoding to /dev/null runs at about 100% CPU but takes about 5 times
> longer to complete)
>
> I have no Idea what's going on, I can only guess, like:
> * Maybe the memory above 64M is not cachable (like plain pentium chips)
> * Maybe the CPU gets warm and the clock is slowed down te prevent damage
> (although the CPU is mostly HALTing)
> * ...
>
> Now I have four questions to you people:
> * This performance degradation seems important to me, is it?
> * What's going on (the hard question) ?
> * Have others noticed this performance degradation too?
> * Can others reproduce this?
>
> I have to admit that I haven't investigated this thoroughly myself, but
> if this is a problem it's not only my problem, so your experience with
> this important.
>
> Rolf
>
>
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