Memory usage of pimpleFoam in parallel

hconel · March 30, 2021, 12:11

Hi,
I am running LES using pimpleFoam on 20 physical cores. Mesh size is around 7 millions. In the Task Manager window, I see 20 "pimpleFoam -parallel" processes, each using 2.4GiB of memory. Does that mean the total memory usage is 2.4 * 20 = 48GB? This looked too much for such a run, but also 2.4GiB total memory usage sounds too small.

65 png

So which one should I consider?
Best regards,
Huseyin

Specs:
24-core AMD Threadripper 3960x CPU
64GiB of memory
OS: Xubuntu 20.04

Tobermory · March 31, 2021, 16:18

The task manager is reporting all the processes. When you decompose to run on 20 processors, you spawn 20 processes ... so each line you see in the task manager is a separate process, each of 2.4GB ... so yes, it is using 48GB in total.

The other way to check total memory usage is to open a terminal and type

Code:

free -h

That will report back the memory usage.

March 30, 2021, 12:11	Memory usage of pimpleFoam in parallel	#1
hconel Member Hüseyin Can Önel Join Date: Sep 2018 Location: Ankara, Turkey Posts: 46 Rep Power: 7	Hi, I am running LES using pimpleFoam on 20 physical cores. Mesh size is around 7 millions. In the Task Manager window, I see 20 "pimpleFoam -parallel" processes, each using 2.4GiB of memory. Does that mean the total memory usage is 2.4 * 20 = 48GB? This looked too much for such a run, but also 2.4GiB total memory usage sounds too small. 65 png So which one should I consider? Best regards, Huseyin Specs: 24-core AMD Threadripper 3960x CPU 64GiB of memory OS: Xubuntu 20.04

March 31, 2021, 16:18		#2
Tobermory Senior Member Join Date: Apr 2020 Location: UK Posts: 670 Rep Power: 14	The task manager is reporting all the processes. When you decompose to run on 20 processors, you spawn 20 processes ... so each line you see in the task manager is a separate process, each of 2.4GB ... so yes, it is using 48GB in total. The other way to check total memory usage is to open a terminal and type Code: free -h That will report back the memory usage.

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