vray ignores cpu affinity/limits on windows 7

[SebastianH]

We're setting up our workstations to help out with rendering (using Deadline 6.1), and we'd like to use only some of the cores during the day so the artists can still go on working. We can't use the thread count to do this, since we'd want to use all the cores on the renderblades and only some on the workstations.

So we used Deadline to set the CPU affinity for each rendernode and when we tested it with mayabatch/Mental Ray, that respected the CPU affinities and took only the amount of cores we set through Deadline. Whereas when rendering with mayabatch/V-Ray (that's V-Ray 2.45), it grabbed all the cores anyway, and there seems to be no way to stop it from doing so.

We've also tried third party tools, such as Process Lasso, to manually set the CPU affinity for mayabatch processes without using Deadline, and got the same result. So this does seem to be a V-Ray issue. Is there any way to make V-Ray for Maya also respect the CPU limits?

This happens with Maya 2014, V-Ray 2.45 on Windows 7 64bit.

Thanks,
Sebastian

[t.petrov]

How are you setting the cpu limits for mental ray/maya software?

[Dariusz Makowski (Dadal)]

Prio - http://www.prnwatch.com/prio/

Worked for me in most of the cases just fine. Give it a go maybe?

[vlado]

I don't think it is a V-Ray issue. Setting the process affinity for mayabatch.exe or vray.exe (depending on which one you are using) works just fine from the Windows Task Manager. In any case, you can always pass explicit number of rendering threads (with -threads option for maya batch or -numThreads=n for V-Ray standalone).

Best regards,
Vlado

[SebastianH]

We first set it through deadline, which passes the setting on to the render slave, and according to what I read about it, all processes spawned by the render slave inherit the cpu affinity, so mayabatch inherits the affinity and should pass it on to any processes it spawns, as far as I know.

Since it didn't seem to work, I tried the Process Lasso tool, which let's you setup a process affinity rule for processes and also shows that information in real time, so I set one up for 'mayabatch', to use only 4 of my 8 cores. Then started a maya batch render.

Rendering with maya/mentalray and auto-render threads, mayabatch stayed at 4 cores actual cpu affinity while loading the scene and while mr rendered.

With maya/vray, process lasso kept reporting 4 cores affinity while mayabatch was loading the scene, but then when vray kicked in, the actual cpu affinity went back to 8 and vray used all 8 cores.

[vlado]

<shrug> I don't think there's much that we can do about that. Use the -threads option instead.

Best regards,
Vlado

[SebastianH]

Well, yeah, if I set the affinity again, after mayabatch/vray started rendering, it does keep it, but it seems that when the vray renderer (started from inside mayabatch) starts up, it overrides the affinity setting. Maybe that's just how it works under windows, but since mentalray seems to respect the limit. (I'm not saying mental ray is better than vray or anything, btw., it's just the only other renderer I have available right now). And I can't really ask the artists here to always go into the taskmanager everytime a render starts on their machine...

Also I can't really use the -threads option, since our renderfarm consists of renderblades and workstations, with different core counts and we'd like to use all cores on the blades and half of the ones on the workstations...

[vlado]

Can you try deleting the vray_Embree.dll file from the V-Ray plugins folder and see if that fixes it?

Best regards,
Vlado

[SebastianH]

Brilliant, that fixed it! Thanks!

Is that file an important part of vray? I mean, would anything fail to render without this plugin? (Wouldn't want to delete that file form our production environment and see all the renders fail mysteriously)

Cheers,
Sebastian

[vlado]

No, if you did not enable Embree specifically, it will be fine.

Best regards,
Vlado

[Dariusz Makowski (Dadal)]

Brilliant, that fixed it! Thanks!

Is that file an important part of vray? I mean, would anything fail to render without this plugin? (Wouldn't want to delete that file form our production environment and see all the renders fail mysteriously)

Cheers,
Sebastian

It meant to speed up ur renders between 5-25% from what I remember, depending on situation... So u might need to run some tests in order to see if u benefit or no... U also need CPU that can handle it.

[vlado]

It meant to speed up ur renders between 5-25% from what I remember, depending on situation... So u might need to run some tests in order to see if u benefit or no... U also need CPU that can handle it.

Yes, but it's not an official 2.x feature anyways. For V-Ray 3.0, I think we have fixed the affinity issue caused by Embree (but I will check to be sure).

Best regards,
Vlado