Very slow render in 3.40.02 with MS 1.3.6.2

[perry2016]

Hi,
We render a test-scene with Multiscatter 1.3.6.2( a lot of tea pots) in Max 2016 with Vray 3.40.02. and we have a pc with 2 x E5-2699-V3 (total 72 cores) in Windows 10

without Vrayspawner it takes 15 mins 16 sec
with vrayspawner it takes 3 mins 1 second

so... why is without Vrayspawner sooooo much slower, both methods we have a 100% cpu load.
In Max 2014 on a single CPU (36 HT cores) (with Vray 3.30.05) same scene renders in 4:51 mins a lot faster compared to the new vray???

I guess the new vray 3.4 has some build in Vraypawner (and get active if there are more than 64 cores), and it is not doing a very good job.
This slow rendering is only the case with MS active , without MS it renders in both ways with the same speed.

[Svetlozar Draganov]

I am a bit confused about the way you submit the rendering.
What exactly do yo mean by "without and with" V-Ray Spawner. Are you rendering on multiple machines or on one machine?
Does the issue appears only on machines with more than 64cores? Would it be possible to perform the same tests with the same Max and V-Ray versions on a machine with less than 64cores?

[perry2016]

yes, one machine (with 2 x Xeon E5 cpu, each 36 cores = total of 72 cores), the scene was rendered 2 times : the first time normally (without distributed rendering enabled aka without the use of Vrayspawner), and the second time with the option Distributed rendering enabled.

The slow rendering only appears on the machines with more than 64 cores
(under windows a programs, like 3dsmax, can only use a maximum of 64 cores, if u have more cores, in my case 72, windows is going to make processor groups, with a maximum of 64 cores available per program.In my case 3dsmax can use a maximum of 36 cores, if I want to utilize all the 72 I need vrayspawner)

[Svetlozar Draganov]

The latest version of V-Ray 3.40.02 has a support for processor groups for systems with more than 64 cores and it should utilize the CPU at 100% by default, so there is no more need to start additional V-Ray Spawners in order to fully utilize the system.

It would be good idea to check if the version of MultiScatter you are using supports V-Ray 3.40.02, there might be some issue with the Multiscatter inself.

Have you already set the environment variable VRAY_USE_THREAD_AFFINITY?

[vlado]

@Svetlozar - Per sent us a scene already and we are looking into it.

Best regards,
Vlado

[perry2016]

hi hard working vray guys
any news on this topic? or did you confirm that there is an issue?
Thanks!

[vlado]

Yes, we can confirm the issue; we are looking for possible solutions. We should get an 88-core machine hopefully next week, so that we can make more precise experiments.

Best regards,
Vlado

[Morbid Angel]

Yes, we can confirm the issue; we are looking for possible solutions. We should get an 88-core machine hopefully next week, so that we can make more precise experiments.

Best regards,
Vlado

Vlado you must have a bunch of multi core machines just lying around the office for all the "testing" purposes

[vlado]

Vlado you must have a bunch of multi core machines just lying around the office for all the "testing" purposes

Well yes, sure, that's how we confirmed the problem However we are also using them for other things...

Best regards,
Vlado

[perry2016]

Any updates or any news on this topic, maybe the nightly builds?

[Svetlozar Draganov]

We are working on that matter now but we are not ready yet.
We'll update the thread when the issue is fixed.

[perry2016]

Yes, finally the problem is solved, after an update from Icube (maker of multiscatter) and many thanks to Vlado for his effort in this matter, very good support from Vray!
We almost render as fast as with the vray spawner option (distributed rendering)

[AlexDuche]

this issue is resolved in MultiScatter from version 1.044