From: forgottenwizard <phrexianreaper@...>
Date: 2007-09-19T01:38:35+09:00
Subject: Re: CPU Usage not near 100% when running code

On 01:03 Wed 19 Sep     , Robert Klemme wrote:
> 2007/9/18, SpringFlowers AutumnMoon <summercoolness@gmail.com>:
> > Robert Klemme wrote:
> > > 2007/9/18, SpringFlowers AutumnMoon <summercoolness@gmail.com>:
> >
> > > Maybe your process is IO bound - probably without you being aware of
> > > it (e.g. through paging, network IO, IPC or such).
> >
> > i can be just running calculations or just the following:
> >
> > require 'benchmark'
> >
> > n = 10_000_000
> > b = 123
> > c = 456
> >
> > Benchmark.bm do |x|
> >   x.report { for i in 1..n; a = b + c; end }
> >   x.report { n.times do   ; a = b + c; end }
> >   x.report { 1.upto(n) do ; a = b + c; end }
> > end
> >
> >
> > If I run the same code on a Mac with single core, the CPU meter will go
> > to 100%.  In the old days when I had a single Intel Windows XP machine,
> > calculation intensive programs will make it go to 100% too.
> >
> > if the Ruby VM uses only one core, then why won't one core go to 100%?
> 
> Probably because the OS moves the process between cores.  See whether
> you can switch off one core or make the process sticky.
> 
> Kind regards
> 
> robert
> 

Might be a stupid question, but could it be that there is a latency
somewhere else that could be slowing you down? The OS is the only thing
that should limit your CPU usage, and unless you're using a system quota
(another possiblity), then it should be able to max out your CPU.