DirectStorage GPU Decompression / RTX IO

I would HOPE... that any developers building games that really require, or take advantage of DirectStorage.. would know how to properly manage their I/O throughput more effectively than not.

Most developers I can see doing the bare minimum.. which should still produce better results than the win32 API. Also, I think once the GPU decompression element comes online, that alone could help many developers improve rapid load times and reduce CPU utilization during streaming.

Seems like there's reasons why it needs to be this complex though... to be able to support future developments in the API and of course future hardware implementations.

 

Atleast we have tech demos again.

Agree on this. If a developer doesnt know how to take advantage of DS, the game probably wasnt worth it technically to begin with.

 

SquareEnix put up a video detailing Luminous Studios' Forspoken technologies.

At 1:53 it shows multiple DirectStorage comparisons on PC using different drives. Loading in just:

1st example
1.9s on an NVMe SSD
4s on a SATA SSD
21.5s on an HDD

2nd example
1.7s NVMe SSD
3.2s SATA SSD
19.9s HDD



It's hard to say how those will compare to the same drives NOT utilizing DirectStorage... but I gotta say... those are some impressive load times regardless.

 

1.7 seconds load time does sound very impressive indeed. Have they any load times for the ps5 version?

 

DS vs no DS comparison would be more interesting TBH.
From this one it seems that NVMe is about twice faster as SATA SSD which to me suggests that the bottleneck is not in storage reads speed.

 

Indeed. Not that I'm aware of... but honestly I can't imagine it being much more impressive than that lol. I think ~2 sec is the usual "optimized for PS5" load time so far.

Yea, it's strange that they opted to not do a comparison NVMe DS on vs off.. but it's all we got for now.

This is without GPU based decompression too.. I wonder what kind of PC they were running for these results?

 

Ok The Verge actually has some answers to our questions

https://www.theverge.com/2022/3/23/22993860/forspoken-pc-microsoft-directstorage-nvme-ssd-gdc

So yea, as we figured.. the game is no longer I/O bottlenecked, but there are other CPU bottlenecks which need to be worked out before it can get much faster. Obviously GPU based decompression is one such incoming feature to help remove the new bottlenecks.

 

When they say m2 ssd they mean nvme yes? because there are sata m2 ssd's

 

I didn't know for sure that DS worked for non-nvme drive. Cool.

 

When I saw the performance bandwidth chart my first question is how SATA SSDs are able to go past 600MB/s, then I realized that the "bandwidth" are likely decompression bandwidth (based on decompressed data size). This makes sense because once they are able to do decompression on the GPU it's likely to be even faster.

 

I don't care that much for loading times. It would be more interesting if DS is used for better world detail and less pop-in. That's what I want to see.

 

So the slides for the Forspoken presentation by AMD and SquareEnix were posted..

https://gpuopen.com/gdc-presentations/2022/GDC_Breaking_Down_The_World_Of_Athia.pdf (11MB)

Some good info there. Decompression and Asset Initialization are the big bottlenecks still preventing things from being faster. GPU decompression should in theory help alleviate both, since the decompression will obviously be quicker, and the data remains compressed until it hits the GPU.

At the end of the day... this is a game with ~1-3sec loading times... It doesn't really matter how we got there.. the point is that we ARE there. 1 to 3 seconds is that for all intents and purposes "instant" loading. DirectStorage may not be much faster over the traditional Win32 API in this specific game.. but we still haven't seen CPU utilization comparisons yet. In game world streaming is where DirectStorage can come into its own in the future.

Given this information, I'm going to assume the PS5 is slightly faster still. Possibly not even having the loading screen flash for a second at all. I can't wait to see the comparisons when they come.

 

It should be, for now, although over 5gb/s is still kinda fast. GPU decompression will make things abit faster.

 

Well, the game isn't really utilizing more than 2.8GB/s from what they've shown.. anything more than that currently is bottlenecked by a different aspect of the CPU > GPU transfer. Yea, GPU decompression should help a bit in this case.. possibly because less data needs to be sent to the GPU over the PCIe bus in that case.

It will still be interesting. At 1-3 seconds.. it's in the realm of "I don't give a damn anymore" lol..

 

I ment the raw read speeds that wherearound 5gb/s with DS activated benchmark.