Xeon CPU cores + affinity

[peterguthrie]

Hello Chaosgroup friends!

I'm doing a project in vray and had a quick question about the number of threads vray uses. I have a dual 18 core xeon workstation which, on win10, prohibits me from changing affinity while rendering. Because of this, my machine is almost unuseable while doing a vray render.

For some reason I never have this problem with Corona. Is there a setting in vray where I can control the number of threads it uses while rendering? In Corona you can additionally set the number of threads to -1 in the system settings. Wondering if there is a similar thing or maxscript I can enter in Vray?

thanks, Peter

[yavor.rubenov]

Hello,

There was a discussion about a similar problem here:
https://forums.chaosgroup.com/forum/...391#post965391

and I've written a small note about changing affinity a few post below it.

Best regards,
Yavor

[rivoli]

does it help if you check "low thread priority"?

[peterguthrie]

sorry for the lack of reply. The env variable does the trick. Would be nice to have the option in vray though

[vlado]

No, we will solve the "issue" in other ways (by reducing the thread priority even further, same as what the Corona guys are doing). Note that you will get the same problem in any heavily multithreaded application.

Best regards,
Vlado

[peterguthrie]

Sounds good!

[king_max]

Hello Chaosgroup friends!

I'm doing a project in vray and had a quick question about the number of threads vray uses. I have a dual 18 core xeon workstation which, on win10, prohibits me from changing affinity while rendering. Because of this, my machine is almost unuseable while doing a vray render.

For some reason I never have this problem with Corona. Is there a setting in vray where I can control the number of threads it uses while rendering? In Corona you can additionally set the number of threads to -1 in the system settings. Wondering if there is a similar thing or maxscript I can enter in Vray?

thanks, Peter

Corona is heavily NUMA dependent and if you check your max CPU turbo speed while rendering with Corona you'll notice that it's actually 200-400 Mhz slower (per core/thread) than it's maximum achievable all-core turbo which Vray pushes. Someone please correct me if I'm wrong.