From: Phil <cmdjackryan@...>
Date: 2007-09-19T01:16:42+09:00
Subject: Re: CPU Usage not near 100% when running code



> -----Original Message-----
> From: John Joyce [mailto:dangerwillrobinsondanger@gmail.com]
> Sent: Tuesday, September 18, 2007 5:03 PM
> To: ruby-talk ML
> Subject: Re: CPU Usage not near 100% when running code
> 
> your cpu is smarter than you.
> the people who design them are smarter than most.
> it's like most things, you would be hard pressed to actually get 100%
> out of it, and if you did, it would probably be bad.
> It probably reserves something for the system.
> most likely a question for a systems engineer or you might look on
> the ars technica site.

Close. It's the OS that usually handles thread scheduling, and it reserves
some power to keep the system responsive. It is actually not that difficult
to get 100% of CPU usage (not recommended on a single-core CPU ;), even
without "badly written software". Video editing or other heavy weight
computational tasks can do that.

This can (and probably is) different for non-x86 implementations (or the
more current variants of x86).

Anyway: that a process doesn't peg out the CPU is a Good Thing in most cases
(in 90% of scenarios, the CPU *time* a thread gets is more meaningful than
the % of cycles).

--
Phillip Gawlowski