Re: Egg on my face -- disk speed

Stephen Williams (steve@icarus.com)
Thu, 05 Nov 1998 22:27:38 -0800


pavel@bug.ucw.cz said:
> It might be nice for our idle process to burn idle cycles and compute
> nuber of cycles burned. This would give pretty accurate numbers.

Some processors will die of heat exhaustion if you do that, especially
if cooling in a case is marginal. I had i960RPs fail that way. I was
able to get 5-10C temperature difference just by putting the halt to
good use. (The i960RD runs much cooler, but still...)

A tight loop that lives entirely in the pipeline is especially evil
(in general) because the processor is at its fastest, is not waiting
for anything, and just causes a lot of switching. I was able to tell
the nature of a loop just by touching the processor chip:-)

Halts are good.

-- 
Steve Williams                "The woods are lovely, dark and deep.
steve@icarus.com              But I have promises to keep,
steve@picturel.com            and lines to code before I sleep,
http://www.picturel.com       And lines to code before I sleep."

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