Page 1 of 1

How to limit CPU use

Posted: Sat Jun 23, 2012 4:20 pm
by EugeneG
I have the opportunity to run F@h on a server with a 6 core (12 allowing for hyperthreading) i7 CPU, but only if it does not interfere with normal work. Alas, it does - it causes the mouse to be jumpy and entered text to buffer up then spit out a chunk at a time. I have allowed it to retain the lowest possible priority and have set the percent CPU usage slider (Configure, Advanced) down to 5%. I saved the config then restarted the computer but still I see F@h is taking about 95% of the CPU at the expense of, for example, a smooth video playback. Is there any way to throttle it back ?

Re: How to limit CPU use

Posted: Sat Jun 23, 2012 4:26 pm
by Jesse_V
Is F@h only using the CPU? Those sound more like some of the occasional side-effects of running F@h on a GPU.

I'm not sure that the CPU slider actually works properly. One sure way is to tell F@h to use one less CPU core or there abouts. Here's how to do that: 1) Set V7 to Advanced mode using the drop-down menu in the top right-hand corner, 2) Click the Configure button, 3) go to the Slots tab, 4) Select the SMP slot and hit the Edit button in the bottom right hand corner, 5) Change the number of CPU cores F@h can use to 10, 6) Select OK and hit Save.

Re: How to limit CPU use

Posted: Sat Jun 23, 2012 5:30 pm
by Meh_Lay_Lay
Yes, leaving 2 threads for other applications should be great. I would advise setting the CPU priority back to "slightly higher" and the usage to 100% too.
Actually, you should check the percentage of CPU usage when not folding, then decide on how many threads you should use to fold.

Re: How to limit CPU use

Posted: Sat Jun 23, 2012 6:35 pm
by EugeneG
That seems to be doing it, thanks. Although all 12 cores are in use, the total is down to 83% and performance of other apps has improved. The priority of 'slightly higher' seems to be ignored like the CPU %. Limiting core slots seems to be the way to go.

Re: How to limit CPU use

Posted: Sun Jun 24, 2012 12:40 am
by bruce
The jumpy cursor is generally associated with the GPU projects. That's on the list of things the Pande Group intends to fix in the GPU cores. I don't believe that the GPU cores respect the Lowest/Slightly Higher setting.

The SMP core does recognizes the Lowest Possible/Slightly Higher setting, but the actual effect depends on the task scheduler in your OS. If you still need to limit the CPU utilzation, reducing the number of CPU cores per Jesse+V's suggestion is the best way to go, particularly if we're talking about a HyperThreaded CPU, though in most cases, an unbiased observer (who doesn't look at the number in Task Manager) probably can't tell the difference. If you're satisfied with your results, though, it doesn't matter what you did to get it to work.