Multisim 11 only uses one CPU core during simulation

[bartgrefte]

Hi,

Just recently I've been using MultiSim again, v11 if that matters, and simulating goes slow, to my opinion that is.

Now there are two things that I've noticed:

- Multisim only uses one of two CPU cores during simulation, not both;

- I've enabled CPU throttle (AMD's Cool'n'Quiet) but corespeed remains very low even though Multisim needs CPU power while simulating.

The simulating of a NE555-based LED-flash circuit requires about 28 seconds to get to 100ms in the simulation. Now if I can get the CPU to throttle up, by for example having Prime95 stress one of the two cores, then the simulation only requires 12 seconds to get to 100ms.

So here are my two questions:

1. Is Multisim 11 capable of using more than one CPU core while simulating? If yes, how can I get it to use more than one?

2. Probably not the right forum to ask, but is there a way to force Windows 7 Ultimate x64 to throttle up the CPU when Multisim starts simulating? Since Multisim does not seem to stress the only core it uses enough to throttle it up. Using Prime95 on one core does trigger a throttle up.

With regards,

Bart Grefte

Relevant specs:

Windows 7 Ultimate x64

Multisim v11

AMD A4-3400

16GB RAM

[cedhoc]

Hello Bart,

Quick reply to your questions:

1. No, Multisim does not support multicore for the moment. 

2. I'm not sure it is possible to have a direct control on the CPU frequency. I think that the Cool'n'Quiet feature actually looks at the CPU usage, which is controled by Windows, in order to set the CPU frequency. Thus, you can try to change the "Minimum processor state" to 100% (under "Processor power management" of the "Advanced power settings"). This is just a guess, but probably Prime95 actually modifies those power management features of Windows. 

[bartgrefte]

Completely forgot this topic....

Is there a good reason why there is no multicore support? Multisim can certainly use it for simulating.

As for the CPU throttling, I found a batch that can increase/decrease the "minimum processor state"-setting and it works immediately, no reboot required.

----------------------------------------------------------------------------------------------------------------------------------------------------
@echo off

powercfg.exe -getactivescheme > "%userprofile%\appdata\~apo.tmp"
set /p v_currentscheme= <"%userprofile%\appdata\~apo.tmp"
set v_currentscheme=%v_currentscheme:~24,36%
del "%userprofile%\appdata\~apo.tmp"

powercfg -setacvalueindex %v_currentscheme% 54533251-82be-4824-96c1-47b60b740d00 893dee8e-2bef-41e0-89c6-b55d0929964c %1
powercfg -setdcvalueindex %v_currentscheme% 54533251-82be-4824-96c1-47b60b740d00 893dee8e-2bef-41e0-89c6-b55d0929964c %1

powercfg -s %v_currentscheme%
exit
----------------------------------------------------------------------------------------------------------------------------------------------------

Usage is simple:
Start -> run -> c:\pathtobatch.bat 100
for "minimum processor state"-setting at 100%

Start -> run -> c:\pathtobatch.bat 5
for "minimum processor state"-setting at 5%

Please note that "set v_currentscheme=%v_currentscheme:~24,36%" is not the same for every language. The original batch had "set v_currentscheme=%v_currentscheme:~19,36%" (most likely for the English version of Windows 7), but since my Windows install is in Dutch, I had to change it in order for it to work.

Running the batch with @echo off removed will show why.

[bartgrefte]

Just tried Multisim 12, still no support for using more than one CPU core while simulating....

[ThiCop]

Hello Bart,

Is it ok for you that I first double-check with my colleague to see how he has already forwarded your feedback to the appropriate people?

Normally he should be back in the office during the course of next week.

Is there anything else you would want me to look into (next to your request for multicore support)?

[bartgrefte]

Sure, fine by me 🙂

Nope, just the multicore support. That other CPU issue is (as far as I can tell) Windows related, don't think something can be done about that on Multisim's end.

[ThiCop]

Hello Bart,

I'll let you know once I've had the chance to talk to my colleague.

[ThiCop]

Hello Bart,

I have discussed it with the colleague and contacted the appropriate Product Managers internally.

At this moment there ar e no immediate plas to change this, but it is considered for longer term development.

This left aside, I'm still very eager to look with you into how we can improve the performance you're getting. (eg. other simulation settings, issues with component models, ...)

In version 12 and 13 there have significant improvements in benchmarks comparing to older versions and other SPICE simulators in the market.

[bartgrefte]

"At this moment there ar e no immediate plas to change this, but it is considered for longer term development."

Hmm, I would expect something that can influence performance significantly be implemented a bit sooner instead being considered for longer term development 😉

Version 13? When is it gonna be released?

[ThiCop]

Hello Bart,

Concerning release dates and reasons for certain R&D choices I cannot provide feedback since I don't know this information.

(Even if I would know some prerelease stuff, then I would most likely not be allowed to publically disclose this information)