Problems running in 64 bit mega PC

[Peter Davies 0]

Hi,

 

We have recently started using the OmniThreadLibrary in our software to increase our scalability.  It is showing great signs of doing this so far.  We have today hit a major snag however.

 

We tried running the code on a 96vCPU machine with 360+ GB of memory...

 

The simple loop we are trying to create fails at the first hurdle with a 'Range Check Error', I traced this to the FNumTasks assignment.

 

I can try and code around that but the loop then doesn't execute.  

 

Any clues?

 

I can get an example up later if required.

 

Thanks in advance,

 

-- Peter.

[David Heffernan 2288]

Is it 96 cpus, or 48 with 2 threads per core? Is the memory NUMA? 

[Peter Davies 0]

Hi,

 

It is 48 with 2 threads per core

 

AWS Virtual Machine, m5a.24xlarge

 

as specified here: AWS Specs

 

Thanks,

 

-- Peter.

[David Heffernan 2288]

Don't try to use more than 48 threads in that case

[Peter Davies 0]

3 hours ago, David Heffernan said:

Don't try to use more than 48 threads in that case

Happens with Just 15...

 

I'll get some code up tomorrow.

 

-- Peter.

[Peter Davies 0]

Well, this is weird...

 

So I put together a test application to post...

 

And it works... we must be pulling in something which is redefining an API call or something...

 

I'll update if/when I find anything...

 

-- Peter.

[Peter Davies 0]

OK,

 

so just changed line 3755 of OtlCommon.pas to:

 

  affMask: NativeUInt;

 

instead of:

 

  affMask: DWORD;

 

and it's off and running...

 

This has to be a bug no?

 

-- Peter.

[David Heffernan 2288]

Affinity masks for pointer sized. 

[Peter Davies 0]

17 minutes ago, David Heffernan said:

Affinity masks for pointer sized. 

I'm sorry but I don't understand?

 

affMask receives the Result of 'Mask' which returns 'NativeUInt' not DWORD....

 

-- Peter.

[David Heffernan 2288]

I mean that this thing is named as though it is an affinity mask. And on Windows that makes it pointer sized. So, NativeUInt. 

[Peter Davies 0]

15 hours ago, David Heffernan said:

I mean that this thing is named as though it is an affinity mask. And on Windows that makes it pointer sized. So, NativeUInt. 

So you are agreeing that it should be NativeUInt not DWORD 😄

[David Heffernan 2288]

Yes, if it is an affinity mask then it should be NativeUInt.