Limited CPU cores usage

[petnek]

Hello,
I plugged in older laptop with i5-2410M CPU. 2 cores, 4 logical. Without any changes in setting, it started to compute some WU (don't know project) on just 2 logical cores. So I changed setting of the slot from -1 CPU to 4, but without result. When I added additional slot limited to just 2 logical cores, it downloaded WU and 1WU is sucesfully uploaded.

Now I have on that machine projects 13628 and 13827. Both slots are limited to 2 cores and one of them is using just 1. In Task manager I see only 25% usage, other is 53%.

Is it ok? Are some projects limited to some amount of cores? I don't wanna waste computational power...

[JimboPalmer]

The first WU any computer does uses 1 core. I do not know why. After that it uses the amount you specify.

[bruce]

The first WU any computer does uses 1 core. I do not know why. After that it uses the amount you specify.

I have a guess as to why. A new installation of FAHClient apparently initilizes the CPU count to either 0 or 1 before it actually checks how many cores are supported by your hardware. The first WU probably downloads before the -1 setting notices you can have more. Depending on several factors, the setting is then increased to 2 or 3 or 4 for the next WU.

Any WU takes note of the number of Cores in effect when it was downloaded. You can adjust that number download but not upward -- so the first WU is limited to cores=1 until it finishes.

I suppose if someone knew this they could probably manually set it to 4 before allowing the first WU to download, but nobody is smart enough to try that on a new installation.

[petnek]

On second computer, first WU was using all 12 logical cores.

I'll try on that laptop change one slot for all cores and will see what happens. But third downloaded WU is using only one core even when in setting is allowed to use 2

[bruce]

...But third downloaded WU is using only one core even when in setting is allowed to use 2

Take a look at the log showing when that WU was first downloaded. Did it start out as 1 or as 2?

You should see something like this:
09:29:05:WU00:FS00:Connecting to xxx.xxx.xxx.xx
09:29:06:WU00:FS00:Downloading x.xx4MiB
09:29:08:WU00:FS00:Download complete
09:29:08:WU00:FS00:Received Unit: id:xx state:DOWNLOAD error:NO_ERROR project:xxxxx run:xx clone:xx gen:xx core:0xa7 unit:xxxxx
09:29:17:WU00:FS00:Starting
09:29:17:WU00:FS00:Running FahCore: "C:\Program Files (x86)\FAHClient/FAHCoreWrapper.exe" C:\Users\bruce\AppData\Roaming\FAHClient\cores/cores.foldingathome.org/v7/win/64bit/Core_a7.fah/FahCore_a7.exe ..... -np 6
where the -np value is important (I had 6 threads allocated to this slot when it was downloaded at 09:29:08 ... above)

Assuming I had allocated 7, there would have been a later message saying "7 was lowered to 6" or something like that ... since 7 is disallowed ... GROMACS doesn't like that number of threads.

[petnek]

Unfortunately, I reconfigured slots, so log is without that information. But I'll look at it when next WU will be downloaded and write here my findings. Thanks for help