VEGA64 performance... again

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grabough

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VEGA64 performance... again

PostSat Feb 16, 2019 7:03 pm

Hey everybody!
I posted on this issue before here https://forum.blackmagicdesign.com/viewtopic.php?f=21&t=84529, which was full of good and bad information. But I since have performed much more tests with Resolve Studio 15 on Windows 10.

My issue is this: I am using H.265/HEVC clips in a simple test timeline using a forward and a reverse clip, applied a bit of global and selective grading, with lens distortion and rotation for good measure.

In that test, the VEGA64 performance (export speed and playback speed) sits between a GTX1060 and an old GTX970. The most shocking part is that the task manager reports a 10% activity from the VEGA card (I tested latest and older drivers), while a 960, 970, 1060, 1070 all seem to use between 50 and 100% of their power according to the task manager.
It looks like the VEGA64 has unused power just doing nothing. The CPU (Ryzen 1700X) is at 95%, while with a 1060 for example the CPU is a 60% usage.
On my system, the 1070 manages to be faster than the 1060, so I don't think I am bottlenecking much.

What's the deal here?
Is this normal?
Puget systems reports here: https://www.pugetsystems.com/labs/artic ... ance-1238/ that the VEGA64 has better performance than a 1080TI using H.265 clips and some grading. I tried auto settings and manually selecting the card and openCL settings. No difference.

There must be something wrong here? But I don't see why. The system is a fresh install as well.
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Jack Fairley

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Re: VEGA64 performance... again

PostSat Feb 16, 2019 7:51 pm

Your CPU is bottlenecking you heavily. H.265 is extremely heavily compressed, which means it's very demanding on the CPU to play back. With the Nvidia cards, you were playing the H.265 files with hardware decoding, which let the GPU work as fast as possible, hence the higher activity, and the better performance with the 1070.
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MishaEngel

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Re: VEGA64 performance... again

PostSat Feb 16, 2019 8:49 pm

BMD DR still doesn't support hardware encoding/decoding for AMD cards.

In many cases opensource software beats the crap out of Davinci Resolve.
For final render nothing beats StaxRip.

It's time Apple puts some pressure on BMD with respect to hardware enconding/decoding of H.264/265.

BMD is in the pocket of NVidia, like many other software vendors.
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grabough

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Re: VEGA64 performance... again

PostSat Feb 16, 2019 9:52 pm

But but but... Way weaker CPUs easily decode H.265 in real-time. Heck my phone does it. What else is needed? If VLC media player can play it back without the CPU going nuts, why is the CPU all of a sudden such a big bottleneck in resolve?
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Trensharo

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Re: VEGA64 performance... again

PostSat Feb 16, 2019 10:16 pm

grabough wrote:But but but... Way weaker CPUs easily decode H.265 in real-time. Heck my phone does it. What else is needed? If VLC media player can play it back without the CPU going nuts, why is the CPU all of a sudden such a big bottleneck in resolve?

I'm pretty sure Phones use SIPs to Accelerate Decode of this media :-P

The way a media player plays back a video is not the same as the way an NLE has to process the video when editing. You fundamentally misunderstand how these things differ, and why playback in VLC is non-problematic, while Resolve bottlenecks.

MishaEngel wrote:BMD DR still doesn't support hardware encoding/decoding for AMD cards.

In many cases opensource software beats the crap out of Davinci Resolve.
For final render nothing beats StaxRip.

It's time Apple puts some pressure on BMD with respect to hardware enconding/decoding of H.264/265.

BMD is in the pocket of NVidia, like many other software vendors.

The bias towards Intel + Nvidia for this stuff is prevalent throughout the industry. It's not a DaVinci Resolve thing :-P

Software companies don't have unlimited developers, and developers don't have unlimited hours for work. Priorities have to be made. Market share often dictates those priorities.
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MishaEngel

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Re: VEGA64 performance... again

PostSat Feb 16, 2019 10:49 pm

Trensharo wrote:The bias towards Intel + Nvidia for this stuff is prevalent throughout the industry. It's not a DaVinci Resolve thing :-P

Software companies don't have unlimited developers, and developers don't have unlimited hours for work. Priorities have to be made. Market share often dictates those priorities.


True, that's why almost nobody uses the SDK for BRAW, not because its hard to implement but because of politics. It easier to get paid to not implement it than to implement it.

Lot's of opensource software programmers don't even get paid, still StaxRip has it and it's faster than any other software. VirtualDub2 is an other great opensource program.
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grabough

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Re: VEGA64 performance... again

PostSun Feb 17, 2019 8:57 am

Ok, but how come the external Black magic eGPUs are AMD VEGA cards? For use with more or less underpowered CPUs in laptops?
What's the magic here all of a sudden?

And can somebody explain how decoding in resolve is so much different (what is?) as compared to a media player?
I guess a media player can forget about a frame as soon as it is played, while in resolve it has to stick around for further processing, but other than that...? The feed is decoded to the best quality possible.
Furthermore the VEGA cards do hardware HEVC decoding.
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Micha Clazing

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Re: VEGA64 performance... again

PostSun Feb 17, 2019 12:22 pm

grabough wrote:The most shocking part is that the task manager reports a 10% activity from the VEGA card (I tested latest and older drivers), while a 960, 970, 1060, 1070 all seem to use between 50 and 100% of their power according to the task manager.
It looks like the VEGA64 has unused power just doing nothing. The CPU (Ryzen 1700X) is at 95%, while with a 1060 for example the CPU is a 60% usage.
On my system, the 1070 manages to be faster than the 1060, so I don't think I am bottlenecking much.

I've observed that the Windows 10 task manager reads GPU usage incorrectly on AMD GPUs. What's more telling is the CPU usage: if the 1060 is only giving you 60% CPU usage, it means it isn't processing frames fast enough and is starving the CPU of work to do. The 95% CPU with Vega likely means the GPU is keeping up with the CPU in terms of providing work for it.

You haven't told us anything about frame rates though; are your frame rates lower than what Puget tested?
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peterjackson

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Re: VEGA64 performance... again

PostSun Feb 17, 2019 1:36 pm

As others have said correctly, Resolve cannot use HW decode / encode with AMD cards, only Intel and Nvidia. Other software like VLC can. Use Hwinfo to get accurate usage readings, not task manager.
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grabough

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Re: VEGA64 performance... again

PostSun Feb 17, 2019 10:04 pm

Micha Clazing wrote:I've observed that the Windows 10 task manager reads GPU usage incorrectly on AMD GPUs. What's more telling is the CPU usage: if the 1060 is only giving you 60% CPU usage, it means it isn't processing frames fast enough and is starving the CPU of work to do. The 95% CPU with Vega likely means the GPU is keeping up with the CPU in terms of providing work for it.

You haven't told us anything about frame rates though; are your frame rates lower than what Puget tested?

I thought exactly the same with the CPU usage... But then it is apparently busy with decoding the stream, while the Vega is bored to death...

It is probably hard to compare whatever Puget is doing with my stuff. For example, I don't have the same CPU and footage.
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grabough

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Re: VEGA64 performance... again

PostSun Feb 17, 2019 10:06 pm

peterjackson wrote:As others have said correctly, Resolve cannot use HW decode / encode with AMD cards, only Intel and Nvidia. Other software like VLC can. Use Hwinfo to get accurate usage readings, not task manager.

Is that on windows only? Because Blackmagic sells AMD cards in their eGPUs... It would be a stupid move from them if they are buddies with Nvidia and if AMD does not hardware decode in Resolve, wouldn't it?
It's all quite bizarre o.O
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peterjackson

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Re: VEGA64 performance... again

PostMon Feb 18, 2019 6:29 am

grabough wrote:
peterjackson wrote:As others have said correctly, Resolve cannot use HW decode / encode with AMD cards, only Intel and Nvidia. Other software like VLC can. Use Hwinfo to get accurate usage readings, not task manager.

Is that on windows only? Because Blackmagic sells AMD cards in their eGPUs... It would be a stupid move from them if they are buddies with Nvidia and if AMD does not hardware decode in Resolve, wouldn't it?
It's all quite bizarre o.O
Mac is different, as Resolve there uses OS services for H26x decode/encode.
5950x, 3090, 128GB.

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