Tech note on multiprocessing

[A Nonny Moose 8,261]

I have been aware for some time that some members have had success with running the game with multiprocessing enabled, and I had run experiments that showed this does indeed work.  However, they were quick empirical tests of short duration.

 

Today, I change the -CPUCount parameter to 2 and ran my very largest city.  The session lasted 17 minutes and I make the following comments:

 

1. I ran the System Monitor program on a second desktop.  It clearly showed that the program was using the second processor, and graphically the indication was that the load was being shared pretty much equally with a maximum of 60% of each processor.  The statistics panel often showed the CPU usage over the 50% mark (of one processor) which can only happen if you are using more than one CPU.
    
2. The game, which at this density of over 825K Sims on a large tile, mostly filled up, ran much more smoothly.  From the way the processors were divided (running in software rendering), I conjecture that the multitasking was split between the simulation and the display processing.  Went very well, while it lasted.
    
3. I managed to do some internal saves while running, but when I tried one the game crashed immediately, terminating my session.

 

I reset my CPU count back to 1.  I don't crash much at all with this setting.

 

From this little test I conclude that the game accumulates whatever causes crashes more quickly if you give it more processor.  Not terribly surprising.  I conjecture that more frequent internal saves might solve this, and even though they are faster in this situation, I am afraid that the game is not worth the candle in this regard.

 

This test was run under control of Ubuntu 14.04 LTS with wine-1.7.17.

 

If anyone with a Windows system tries this, please add your results to this thread.  If you have some way to monitor your session it would be useful. Thanks.

[SpookyZalost 39]

I can happily report both on win 7, that my quad core 64bit system does not cause sc4 to crash even after what is now about 5 hours of play so far, I did try it before that and had it crash when using a NAM item, but it's a known issue.

System specs are as follows.

CPU: amd athlon II x4 640 64bit
OS: win 7 ultimate x64
Memory: 4gb DDR3
GPU: Nvidia 520GT PCI-E
HDD, Seagate GoDesk 2TB (that's where it's installed to)
Version: Sc4 Steam ver, modifiers for 1920x1080 resolution

confirmed as using all 4 cores, no modifiers to core setup.

System is a desktop.

[A Nonny Moose 8,261]

I suspected as much.  Were you able to get any CPU measures while the program was running?  I don't know what instrumentation is available on Windows any more. 

 

Could you show that the game was actually using all cores simultaneously?  My machine only has 2 cores, and they were used equally at the same time according to my system monitor.

[SpookyZalost 39]

I suspected as much.  Were you able to get any CPU measures while the program was running?  I don't know what instrumentation is available on Windows any more. 

 

Could you show that the game was actually using all cores simultaneously?  My machine only has 2 cores, and they were used equally at the same time according to my system monitor.

this is after I tabbed out having let the game run for several hours, all 4 cpu's are used, and it appears steam is using one more than the others.

[A Nonny Moose 8,261]

Looks to me like only one processor is doing much with the game.  You have 90 processes in there doing something, and Windows service are always doing something.

 

My system monitor operates on a per process basis.  Here is the kind of display I get with only firefox running in app space.

 

[SpookyZalost 39]

hmm, Idk, I did check the system processes and the affinity was set to all, maybe there was a bugfix in the steam version?

[A Nonny Moose 8,261]

Wouldn't bet on it.  I think it is just plain 1,1,641,0.  Not different from the commercial offering from Amazon except Steam has a funny idea about where things should be installed, and that you should tell them when you run.