CPU Usage %

[Markleshark]

So, basically, its just one of those things I don't know...

I was wondering if someone (Pretty broad question, I know) could explain how CPU usage percentage works. Coz I have a CoreDuo Mac Mini, all that I understand, one processor, 2 cores, etc, etc. So will that show as 200% CPU, or is that for 2 physical processors?

Just an explanation would be nice, just one of those things I've not really got round to understanding.

Cheers Peeps
Mark

 

[robbieduncan]

2 cores is the same as 2 physical processors in this case, so yes max is 200%.

 

[dextertangocci]

Yes, in activity monitor you'll see 2 graphs showing the processor percentage used per core

 

[LeviG]

um, I was under the impression that it was only 100% total (admittedly more windows based on this)

each cpu/core is equal to 50% of the overall performance of the system/cpu. The individual graphs show the percentage of that 50% that is being used on each core/cpu.

So say you have 1 core running at 25% and the other at 50% use the overall use would be (25% of 50% = )12.5% and (50% of 50% =) 25% which would give a 37.5% overall cpu percentage.

If both cores/cpus are running at full speed (ie 100% each) then the overall cpu percentage would only be 100% due to the fact that 100% performance for the cpu/cores would be the combined performance of the cpu/cores.


Maybe macs register the information differently to pcs but the above is my understanding of it.

 

[Nutter]

I don't know how it works in Windows, but in Activity Monitor 100% does represent only a single CPU core, as robbie said.

 

[robbieduncan]

Maybe macs register the information differently to pcs but the above is my understanding of it.

OSX is a Unix so follows the long established Unix standard process of each core or CPU being 100%. So on a Mac Pro you can have 400%!

 

[wmmk]

OSX is a Unix so follows the long established Unix standard process of each core or CPU being 100%. So on a Mac Pro you can have 400%!

or 800% if you're good at doing hardware mods

 

[robbieduncan]

or 800% if you're good at doing hardware mods

And have a lot of cash

 

[Markleshark]

Thanks for the replies guys, as I say, just something I never got my head around.

However, when I take a picture of AM, I still get 2 graphs, for both cores, but the usage percentages only add up to 100%. Will I see more percentage as I do more CPU intensive things (Video Encoding, etc)

 

[LeviG]

I don't know how it works in Windows, but in Activity Monitor 100% does represent only a single CPU core, as robbie said.

windows has two ways of displaying the graphs
1) single graph showing current cpu usage total (100%) with a single window showing history/current cpu usage.

2) single graph showing total cpu usage (100%) and 2 or more graphs showing cpu history/current cpu usage

the history/current cpu has no numbers saying actual amount though.

EDIT: although this is only in task manager other programs available display the same info slightly differently

 

[ATD]

Here's Maya rendering with mental ray on a quad. The bottom bar is a utility that shows total use of each cpu.

 

[Markleshark]

Here's Maya rendering with mental ray on a quad. The bottom bar is a utility that shows total use of each cpu.

Awesome stuff.

Could you tell me where to get that Menu Bar add on, pretty please.

 

[ATD]

Awesome stuff.

Could you tell me where to get that Menu Bar add on, pretty please.

http://www.ragingmenace.com/software/menumeters/

 

[Markleshark]

http://www.ragingmenace.com/software/menumeters/

Thank you kindly, good sir.

 

[jsw]

Thanks for the replies guys, as I say, just something I never got my head around.

However, when I take a picture of AM, I still get 2 graphs, for both cores, but the usage percentages only add up to 100%. Will I see more percentage as I do more CPU intensive things (Video Encoding, etc)

Keep in mind that you've only got it set to show your processes, so those of the system and any other logged-in users won't show. Set it to "All Processes" (top rightdrop-down) to see them all.

 

[wmmk]

And have a lot of cash

heh. i was going to say that!