CPU Usage Limitation in XP 64-Bit

[Scinarious]

Good morning!

I have a quick question about the CPU usage limitation in the XP 64-bit. I am running a computational demanding software (COSMOSWorks - Finite Element Analysis) and the problem is COSMOSWorks FEA software (64-bit) is only using 25% of the CPU. The computer has 2 Intel Xeon 5140 (dual cores) so in the "Task Manager" it seems like it has 4 CPUs but the FEA "process" is only using 25% and will not go any higher. I have tried setting the Affinity in the Task Manager to CPU 0, CPU 0 & CPU 1, CPU 0 - 1 - 2, and CPU 0-1-2-3. All of the combinations only use 25%. At which point, I installed 32-bit software and I am able to control the CPU usage which goes from 25% for 1 CPU to 100% for 4 CPUs.

Would anyone know how to change the CPU utilization for the software?

Thank you very much!

[bledd]

its the program and not windows that is limited (i've never used the program mind)

not all programs are optimised for multiple cpu's or cores

[cluberti]

Also, since that's a 32bit app on an x64 platform, there's some emulation in system calls between the WOW64 subsystem and the processors that setting affinity isn't going to resolve. It's likely that the application does not work well with the 64bit scheduler, and you'll need an x64 version of the app for it to work properly in x64.

[Scinarious]

Hi cluberti,

I tried using the 64-bit COSMOSWorks with Affinity set to 1 CPU and all CPUs and the CPU usage and solution time were the same. The CPU usage and solution time for all 4 settings were 25% and 4 min 22 sec.

Windows XP 64-BIT & COSMOSWorks 32-BIT

# of CPU---------------CPU Usage----------------------Solution time (min:sec)

1------------------------25%-----------------------------------4:22

2------------------------25%-----------------------------------4:21

3------------------------25%-----------------------------------4:22

4------------------------25%-----------------------------------4:21

When I uninstalled 64-bit COSMOSWorks and installed the 32-bit version. The following results were obtained:

Windows XP 64-BIT & COSMOSWorks 64-BIT

# of CPU---------------CPU Usage----------------------Solution time (min:sec)

1------------------------25%-----------------------------------8:50

2------------------------50%-----------------------------------5:51

3------------------------75%-----------------------------------5:34

4------------------------99%-----------------------------------3:13

So, the 32-bit software is not limiting the CPU usage unlike the 64-bit version. This is the software from the same company

Has any body ever confront with this problem (even if it's on another software) and what did you look for to solve this issue?

Any input is greatly appreciated.

Thank you!!

Edited May 29, 2007 by Scinarious

[cluberti]

Has any body ever confront with this problem (even if it's on another software) and what did you look for to solve this issue?

Well, honestly, at that point I start pestering the vendor to see why this happens with 64bit software on a 64bit platform, because only they'll know how the solution is architected. This is internal code problems, not an OS problem at this point.

[Zxian]

The problem with many FEA solvers is that their matrix solvers are not optimized for multi-threading.

You've got 4 cores total, so a single thread can only use 25% in total - 1 out of 4 cores.

Depending on your budget, you might want to look at Matlab & Comsol. It's a bit pricey, but for FEA or anything of the sort, it's nothing short of amazing. Oh.. and both work great in x64 and with multiple cores.