Measuring CPU with Hyperthreading and Linux

Measuring CPU with Hyperthreading and Linux

[Matthew A. Miling]

Hello

Please personally CC my email address to any responses:
  mamiling@syr.edu

I am currently running a dual Pentium 4 Xeon 2.4 GHz system containing Red Hat 
Linux 6.2 with the 2.4.20 kernel.  The Pentium 4 Xeons report 4 cpu's to 
/proc/cpuinfo because they are hyperthreaded.

My problem lies in trying to measure the CPU usage with such programs as top 
or gtop.  Typically, I see CPU loads in excess of 100% when I run top with 
some of my signal processing applications, but not more than 200%.  Is this 
value out of 100%, 200%, or 400%?  How does this dual, HT system kernel report 
this info to the OS?

Any help would be appreciated.  Thanks

Matt

-------------------------------------------

 Matthew A. Miling
 Graduate Student - Computer Engineering
 Syracuse University

 phone:  (315) 456-1215
 cell:   (315) 380-9307
 e-mail: mamiling@syr.edu
         matt@miling.com

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Re: Measuring CPU with Hyperthreading and Linux

[Andrew Walrond]

Run top, then press 1 to get a 'per cpu' usage line, rather than the 
default combined thing.

Obviously you'll need a threaded app to take advantage of the 
processors, and preferably a 2.5 kernel with  Ingo's HT scheduler patch...

Andrew

Matthew A. Miling wrote:
> Hello
> 
> Please personally CC my email address to any responses:
>   mamiling@syr.edu
> 
> I am currently running a dual Pentium 4 Xeon 2.4 GHz system containing Red Hat 
> Linux 6.2 with the 2.4.20 kernel.  The Pentium 4 Xeons report 4 cpu's to 
> /proc/cpuinfo because they are hyperthreaded.
> 
> My problem lies in trying to measure the CPU usage with such programs as top 
> or gtop.  Typically, I see CPU loads in excess of 100% when I run top with 
> some of my signal processing applications, but not more than 200%.  Is this 
> value out of 100%, 200%, or 400%?  How does this dual, HT system kernel report 
> this info to the OS?
> 
> Any help would be appreciated.  Thanks
>