Discussion Groups

Simulation CFD

Reply
Active Member
sveenman
Posts: 6
Registered: ‎11-03-2012
Accepted Solution

16 Core Machine only using 8 Cores

516 Views, 11 Replies
11-03-2012 08:36 AM

I have a dual 8 core workstation that I send jobs with the remote solving feature in CFD.  When I tell it to use all 16 cores it only seems to load the workstation to about 50% or half the cores.  What might I need to change so that it will use all 16 cores.

 

Thanks

Please use plain text.
Product Support
Royce_adsk
Posts: 588
Registered: ‎08-24-2011

Re: 16 Core Machine only using 8 Cores

11-05-2012 05:39 AM in reply to: sveenman

Are you sure it is really 16 pysical cores? Many people get confused when hyperthreading is turned on and task manager says there are 16 cores when really there are only 8 physical cores.

 

What are your CPU Hardware Specs?

 

-Royce



Royce Abel
Please use plain text.
Active Member
sveenman
Posts: 6
Registered: ‎11-03-2012

Re: 16 Core Machine only using 8 Cores

11-05-2012 06:16 AM in reply to: Royce_adsk

I talked with our IT guys and they said it was not using hyper threading.  According to properties under my computer it is a Xeon E5-2680 @ 2.7GHz and the task manger shows 16 cores.

Please use plain text.
Product Support
Royce_adsk
Posts: 588
Registered: ‎08-24-2011

Re: 16 Core Machine only using 8 Cores

11-05-2012 06:26 AM in reply to: sveenman

If you open your resource monitor and review your CPU tab, how many CPUs are listed and how many of them indicated the 'Parked' state?

 

Thanks,

Royce



Royce Abel
Please use plain text.
Active Member
sveenman
Posts: 6
Registered: ‎11-03-2012

Re: 16 Core Machine only using 8 Cores

11-05-2012 06:37 AM in reply to: Royce_adsk

8 of them are listed as parked.  So what does that mean?

 

-Steve

Please use plain text.
Product Support
Royce_adsk
Posts: 588
Registered: ‎08-24-2011

Re: 16 Core Machine only using 8 Cores

11-05-2012 07:00 AM in reply to: sveenman

This means that you have 8 physical cores with 8 virtual cores created with hyperthreading.

 

-Royce



Royce Abel
Please use plain text.
Active Member
sveenman
Posts: 6
Registered: ‎11-03-2012

Re: 16 Core Machine only using 8 Cores

11-05-2012 07:06 AM in reply to: Royce_adsk

Thanks for the help I will let the IT Group know.

 

-Steve

Please use plain text.
Active Member
sveenman
Posts: 6
Registered: ‎11-03-2012

Re: 16 Core Machine only using 8 Cores

11-15-2012 05:18 AM in reply to: sveenman

I have now added a 2nd 8 core cpu to this machine.  When I run a simulation now it uses ~25% of the processors.  So becasue hyperthreading is on that means it is still only using 8 of the 16 actual cores.  What am I missing now?

 

Thanks

Please use plain text.
Active Member
akarlsso
Posts: 7
Registered: ‎08-30-2011

Re: 16 Core Machine only using 8 Cores

11-27-2012 05:42 AM in reply to: sveenman

I remember from an earlier release that in a standard license the solver could use up to 4 virtual cores.

I dont remember which release this came in but it was the greatest enhancement I've seen so far.

 

If this is still the case its likely to be an explanation to why you dont see a performance increase

Please use plain text.
Active Contributor
mikesnidersnider
Posts: 32
Registered: ‎09-03-2013

Re: 16 Core Machine only using 8 Cores

04-28-2014 06:56 AM in reply to: sveenman

Hi,

 

I am the second indian to walk down this path.  My computer "Thor" has a dual processor mother board and my first processors had six cores each, with Intel's hyper threading, Windows resource monitor showed 24 cores.  Thor ran problems using approximately 33 percent of its CPU usage.  Eight of the cores did not run during a calculation and I understood that Sim CFD uses 2! cores (2,4,8,16,32....).   I have upgraded to processors with eight cores each for a total of sixteen physical cores and 32 hyperthreaded which appear in Window's resouce monitor.  Now when Thor runs a test problem with the new processors CPU usage is only 24 percent and twelve cores are idle.  When a problem is loading I have seen utilizations of 98 percent breifly with the eight core processors.  My O.S. is Windows 7 64 bit and all threads are active.  I have tried various core numbers in the job manager and get the same performance.

 

I want to get Thor to swing the hammer harder.  Would reinstalling SimCFD reorient the software to the new hardware enviroment (more cores)?  Is there some licensing issue?  Does the software only support the number of physical cores plus four?  If so, is this an enhancement that is in the works?  When will it be ready and may I have it?

 

I thank you in advance for your time and attention to this matter.

 

Mike Snider

 

Please use plain text.