Folding Forum

Hi guys, I have dual-socket server setup on Win 10 Pro, humming along with a pair of E5-2686v3's.
Each CPU has 18 physical cores (36 logical), so that's 36 physical cores (72 logical cores) in total.

Now, when I fire up F@H, it only acknowledges the presence of 32 logical cores. In addition, all the work only gets allocated to one of the CPUs at any given time, which means I'm missing 4 (and the other 36 from the 2nd CPU).
I can adjust the process affinity to shift the load to one CPU to the other, but it seems that F@H is really fond of using only 1 CPU at any given time.

So my question is, how do I get F@H to recognise the rest of my 40 logical cores, and put them to good use? Turning off HyperThreading didn't do much for performance, so I'm inclined to keep it on.
I can't seem to find a proper answer anywhere, so here's my plea for help

I have one quad Core, so this is not from personal experience. <G>

Have you set up another CPU slot with 32 CPUs, then a third CPU slot with 8 CPUs to make 72 in total?

(if you do not find work for 32 CPUs, you may need to set up 4 slots of 16 CPUs, but if there is work, two slots of 32 will yield more Points Per Day.

Part of what you are running into is that Windows has limits on how many processor threads will be assigned to a single process unless certain configuration and programming steps are taken. There was a similar problem posted here within the last few months, I will provide a link to it if I find it.

Does it have anything to do with this article on processor groups?
https://msdn.microsoft.com/en-us/librar ... s.85).aspx

As long as you're using a 64-bit version of Windows you should be able to make this work. The client has a default maximum of 32 threads but you can configure the slot to use 72 if you wish. The problem right now is that there's no work available for that number of cores and it's a holiday weekend in the US so the lack of work may not be corrected until at least Monday.

Using FAHControl (Advanced Control) select Configure, Slots, highlight the slot and click on Edit. Change the -1 in the CPU configuration to 72 and click the appropiate OKs and Save.

As I said earlier there's no work currently available for that high number of cores so you may want to setup 3 slots of 24 each for now.

The software used for SMP folding comes from gromacs.org. It has some pretty significant problems when dealing with certain numbers of CPUs working on a single project, including some newly discovered problems with large numbers of CPUs. Creating multiple slots with "reasonable" (a poorly defined term) numbers of CPUs is the recommended solution.

@bollix47 Thanks I managed to get it to work properly, after messing around with the processor group affinities. F@H/Windows will assign all work to 1 CPU by default. To overcome this, I just had to manually set the processor group affinities for each core. This solution couldn't have come at a better time, because the folding race is due to start in a few hours.

Is there any way to force each F@H core to have it's own permanent processor affinity? When a WU finishes, the FAHcore just defaults back to it's original setting (32 cores on 1 CPU, which means I need to manually adjust the affinities again in Task Manager, in order to make full use of both CPUs.