Implementing NVIDIA PhysX physics engine when NVIDIA is dropping it.

[rbrt09070]

"As part of the 1.54 Open Beta, we are adopting the NVIDIA PhysX physics engine as an alternative to our current Bullet physics engine for low-level simulation of physics in the game world that players interact with."

But the green team announced: "Nvidia dropping 32-bit PhysX from the RTX 50-series' CUDA infrastructure" so support is discontinued, so why switch now?

[Wolfgang]

There is 64bit PhysX which is still supported.

[Wolfpig]

Originally posted by rbrt09070:

But the green team announced: "Nvidia dropping 32-bit PhysX from the RTX 50-series' CUDA infrastructure" so support is discontinued, so why switch now?

Most games, your os and drivers are already 64bit only.
So the only downside for nvidia dropping 32bit Hardware Support is that the old 32bit games which use it seem to run horrible on the software PhysX.

And at some point 32 bit support needs to be dropped to reduce unneeded backporting.

[Ryu]

This game is 64-bit only, so nVidia dropping 32-bit support of PhysX on their latest GPU series has zero impact. ;)

[Varlo]

This uses CPU PhysX [github.com], which has nothing to do with GPU PhysX. Even if Nvidia entirely dropped hardware-accelerated support for 32-bit and 64-bit PhysX on their cards, it would still function normally because it runs on the CPU. GPU PhysX is no longer actively developed, unlike CPU PhysX.

[J8SUPRME]

Originally posted by Varlo:

This uses CPU PhysX [github.com], which has nothing to do with GPU PhysX. Even if Nvidia entirely dropped hardware-accelerated support for 32-bit and 64-bit PhysX on their cards, it would still function normally because it runs on the CPU. GPU PhysX is no longer actively developed, unlike CPU PhysX.

That is complete nonsense.

PhysX is PhysX - no matter if the GPU or the CPU is doing the number crunching. PhysX is still in development - the 32-bit version is just not supported by the NVIDIA RTX 50xx series. Since ETS2 is a 64-bit game and therefore using 64-bit PhysX, those on RTX 50xx GPU’s won’t have problems.
In the NVCP you can select whether it’s the CPU or GPU that handles PhysX. Since ETS2 is still single core I highly recommend those with NVIDIA GPU’s to manually select the GPU.
There is no such thing as “CPU PhysX” or “GPU PhysX”.
Those on AMD GPU’s are forced to having their CPU do the number crunching. And that’s the challenge with SCS’s decision to switch to PhysX. However - if SCS gets CPU multicore support right it might not be a problem. But right now it kind of is.

[Wolfgang]

Originally posted by Varlo:

This uses CPU PhysX [github.com], which has nothing to do with GPU PhysX. Even if Nvidia entirely dropped hardware-accelerated support for 32-bit and 64-bit PhysX on their cards, it would still function normally because it runs on the CPU. GPU PhysX is no longer actively developed, unlike CPU PhysX.

Not sure if it is actually running on the CPU as this is generally tanking performance even with the best CPUs on the market. Then again there is this in the game.log file in 1.54:

00:00:26.630 : [physx] @0: Created foundation version 1.0.0.
00:00:26.630 : [physx] @0: Created physics version 3.4.3.
00:00:26.630 : [physx] @0: Initialized extensions.
00:00:26.630 : [physx] @0: Created CPU dispatcher with 2 threads and logical CPU affinities:
00:00:26.630 : [physx] @0: CPU          0   1   2   3   4   5   6   7   8   9  10  11  12  13  14  15
00:00:26.630 : [physx] @0: thread   0   *   *   *   *   *   *   *   *   *   *   *   *   *   *   *   *
00:00:26.630 : [physx] @0: thread   1   *   *   *   *   *   *   *   *   *   *   *   *   *   *   *   *
00:00:26.630 : [physx] @0: Created convex cooking.

Which I have no idea how to properly interpret.
Edit: Seems like this is too wide for Steam to handle properly. Sorry for the formating in that case.
Edit2: If it is really running on the CPU then this is a bad decission from SCS as the game is already mainly running on one CPU and it is already basically pegged.

[J8SUPRME]

Originally posted by Wolfgang:

Originally posted by Varlo:

This uses CPU PhysX [github.com], which has nothing to do with GPU PhysX. Even if Nvidia entirely dropped hardware-accelerated support for 32-bit and 64-bit PhysX on their cards, it would still function normally because it runs on the CPU. GPU PhysX is no longer actively developed, unlike CPU PhysX.

Not sure if it is actually running on the CPU as this is generally tanking performance even with the best CPUs on the market. Then again there is this in the game.log file in 1.54:

00:00:26.630 : [physx] @0: Created foundation version 1.0.0.
00:00:26.630 : [physx] @0: Created physics version 3.4.3.
00:00:26.630 : [physx] @0: Initialized extensions.
00:00:26.630 : [physx] @0: Created CPU dispatcher with 2 threads and logical CPU affinities:
00:00:26.630 : [physx] @0: CPU          0   1   2   3   4   5   6   7   8   9  10  11  12  13  14  15
00:00:26.630 : [physx] @0: thread   0   *   *   *   *   *   *   *   *   *   *   *   *   *   *   *   *
00:00:26.630 : [physx] @0: thread   1   *   *   *   *   *   *   *   *   *   *   *   *   *   *   *   *
00:00:26.630 : [physx] @0: Created convex cooking.

Which I have no idea how to properly interpret.
Edit: Seems like this is too wide for Steam to handle properly. Sorry for the formating in that case.
Edit2: If it is really running on the CPU then this is a bad decission from SCS as the game is already mainly running on one CPU and it is already basically pegged.

Are your GPU AMD or NVIDIA? Because your log clearly shows the game setting up PhysX on the CPU.

One thing could be that SCS is forcing PhysX calculations to be done by the CPU no matter what GPU is installed. And that is a really really bad decision. Because that will mean that many players will have their PC going from mediocre to full potato with version 1.54 of the game.

[Wolfpig]

Originally posted by J8SUPRME:

One thing could be that SCS is forcing PhysX calculations to be done by the CPU no matter what GPU is installed. And that is a really really bad decision. Because that will mean that many players will have their PC going from mediocre to full potato with version 1.54 of the game.

Im quite sure that the cpu dispatcher line in the log has nothing to do how physx is used, as the cpu only is dispatching the tasks to the hardware which is set for the task.

As it says on the help page of physx

https://docs.nvidia.com/gameworks/content/gameworkslibrary/physx/apireference/files/classphysx_1_1PxCpuDispatcher.html#_details

A CpuDispatcher is responsible for scheduling the execution of tasks passed to it by the SDK

BTW: As i did a testrun with the beta the nvidia statistiks showed me
80% GPU Usage (rtx 4080 Super) and
around 13-15% CPU Usage which is barely more then before (7800x3d).


Ok, i run the game in 4k locked to 160fps so a bit of load will come from that but it does not seem that physx has some major impact on performance at all..

https://steamcommunity.com/sharedfiles/filedetails/?id=3440514066

[J8SUPRME]

Originally posted by Wolfpig:

Originally posted by J8SUPRME:

One thing could be that SCS is forcing PhysX calculations to be done by the CPU no matter what GPU is installed. And that is a really really bad decision. Because that will mean that many players will have their PC going from mediocre to full potato with version 1.54 of the game.

Im quite sure that the cpu dispatcher line in the log has nothing to do how physx is used, as the cpu only is dispatching the tasks to the hardware which is set for the task.

As it says on the help page of physx

https://docs.nvidia.com/gameworks/content/gameworkslibrary/physx/apireference/files/classphysx_1_1PxCpuDispatcher.html#_details

A CpuDispatcher is responsible for scheduling the execution of tasks passed to it by the SDK

BTW: As i did a testrun with the beta the nvidia statistiks showed me
80% GPU Usage (rtx 4080 Super) and
around 13-15% CPU Usage which is barely more then before (7800x3d).


Ok, i run the game in 4k locked to 160fps so a bit of load will come from that but it does not seem that physx has some major impact on performance at all..

https://steamcommunity.com/sharedfiles/filedetails/?id=3440514066

I got the log file wrong - Wolfgang is then right about the log file being inconclusive on whether the CPU or GPU is doing PhysX.

Since you're on an NVIDIA GPU you might not see any degrading performance. I would much rather hear from someone using an AMD GPU.

[Verzee]

there is frame time skipping in this Beta, could it be connected to Physx?

[J8SUPRME]

Originally posted by Verzee:

there is frame time skipping in this Beta, could it be connected to Physx?

Maybe. If you’re on a NVIDIA GPU try to change the PhysX settings in the NVCP and see if there is a difference between using the CPU or GPU.
I’ve seen the stutter as well but haven’t tested the PhysX settings.

[Wolfgang]

Originally posted by Verzee:

there is frame time skipping in this Beta, could it be connected to Physx?

Please report issues on the SCS Forum as clearly stated in the announcement.

[Madkine]

Originally posted by Wolfgang:

Edit2: If it is really running on the CPU then this is a bad decission from SCS as the game is already mainly running on one CPU and it is already basically pegged.

The existing physics engine is also running on the CPU. So if PhysX requires less CPU, then you gain headroom.
And if they were to use the GPU version, then you'd need an NVIDIA GPU to play the game. They aren't going to suddenly make the game not work for half their customers now are they?

[J8SUPRME]

Originally posted by Madkine:

Originally posted by Wolfgang:

Edit2: If it is really running on the CPU then this is a bad decission from SCS as the game is already mainly running on one CPU and it is already basically pegged.

The existing physics engine is also running on the CPU. So if PhysX requires less CPU, then you gain headroom.
And if they were to use the GPU version, then you'd need an NVIDIA GPU to play the game. They aren't going to suddenly make the game not work for half their customers now are they?

I don’t know if PhysX demands less of the CPU than the old physics engine. If it does then you’re right.
Never the less multi core support needs to be implemented asap.

[Wolfgang]

Originally posted by Madkine:

Originally posted by Wolfgang:

Edit2: If it is really running on the CPU then this is a bad decission from SCS as the game is already mainly running on one CPU and it is already basically pegged.

The existing physics engine is also running on the CPU. So if PhysX requires less CPU, then you gain headroom.
And if they were to use the GPU version, then you'd need an NVIDIA GPU to play the game. They aren't going to suddenly make the game not work for half their customers now are they?

According to Ryu PhysX also runs on AMD GPUs. And from what I read on looking around is that PhysX on the CPU is running very poorly.