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Onur_Atak
Beginner
52 Views

MKL multi-processor problem on windows server 2008

I actually had another thread about MKL and zgemm function and asked this question in that however since the source of my problem was not zgemm I decided to open a new thread about this.
I am connecting to windows server 2008 machinewhich has8 processors (xeon) through remote desktopand trying to run the code that runs fine under win 7. I am using zgemm function of blas which uses multi-threading. On win 7 (my laptop) I can set MKL_NUM_THREADS to 1 or 2 and let the code use one or two processors. However when I try setting these on windows server, it only works when I set the number to 1. I have adminrights on the machine so I believe I should be able to use more than one processor. When I try using more than one, the zgemm function just stops , it does not complain about anything but just keeps occupying same amount of ram and cpu forever.
What I am trying to do is to use all 8 procesors on the server, so should I change something in my code or should I change some options on Windows server ?
I am using MKL version 10.2 with update 4. One more detail is that, the windows serverOS is actually a virtual machine. The serveractually has 16 processorsand there are three virtual machines on that;one with 8 and the other two with 4 processors assigned to them.

Thanks in advance,

Onur
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6 Replies
Gennady_F_Intel
Moderator
52 Views

Onur,
This is a known issue. We is investigating the cause of the problem at this moment.The problem has been escalated to the engineering team. I will inform you asap if any updates regarding this problem.
--Gennady
Gennady_F_Intel
Moderator
52 Views

Onur,
Could you please check theproblemwit thelatestUpdate 5 ( version 10.2) released the last week and which is available on Intel Registration Center.
some memory servicefunctionshas been modified in this update.
Please let us know the result.
--Gennady
Onur_Atak
Beginner
52 Views

I have installed update 5 and recompiled everything accordingly. Unfortunately the problem is not solved. Windows server machine still onlyresponds when I set the number of threads to 1. Was this specific issue about windows server addressed in the update ? If not, when can I expect a solution or a work around to this ?
I only saw issue about 64-bit machines in the update, however in my case Windows 7 is also 64 bit, so I guess the problem should be about different windows versions or processors.

Regards,
Onur

Onur_Atak
Beginner
52 Views

It has been sometime since I created the topic and I was waiting for the next update. Unfortunately update 6 has not solved my problem as well. Ireally need to use multi-processors since I have to run heavy calculations and I am eagerly waiting for a solution. Can you update me about status of the solution tothe problem I described above?
Thanks,

Onur
Gennady_F_Intel
Moderator
52 Views

You observe the same behavior of your program as you described above: When I try using more than one, the zgemm function just stops , it does not complain about anything but just keeps occupying same amount of ram and cpu forever. ?

Let's check those that conduct on the native environment. Could you check it and let us know?

--Gennady



Onur_Atak
Beginner
52 Views

Now I run my simulation on a native windows server 2008 and surprisingly it was able to use multi processors ( just two actually but I think the number does not mean anything as long as it's more than one :)
So now I can say the problem is about virtualisation but I can also assure you that the virtualized windows server is capable of running multi-processor actions like it doeswith nastran. So itshould still be something about MKL and virtualized Windows server.Any suggestion ?

Thanks,

Onur