Also does Kirby have a PS5 developer kit?
I have zero idea. They have Xbox Series X as one of the platforms in their Twitter bio; if they don't have a PS5 devkit then they might know a dev who is working with one and they talk back and forth.
So some serious info in this thread. So we now think 100gb has a direct connection to cpu/gpu? So less latency for direct access the it would be to copy into RAM. That is very different then what sony has.
Well, there's a lot of info but there's also a lot of speculation, to be perfectly fair. It's possible both systems have direct CPU/GPU connections but one prioritizes that (at the expense of slower/more overhead writing to RAM) and the other prioritizes writing directly to RAM (at the expense of slower/more overhead with direct CPU/GPU access).
From what we've seen of the PS5, the I/O complex has a direct path to the system RAM, so the assumption is that the system is able to utilize that to write out required data to RAM rather than having the CPU do it (the CPU still communicates with the I/O complex to instruct what data to write to the RAM though, or what data to take from RAM and write back out to storage). We didn't see any connection from the I/O complex to the GPU and given the focus Cerny put on the SSD in that presentation, if that was a feature, they surely would've highlighted it at the event since it's kind of a big deal.
The thing though is that since PS5's I/O complex handles data transfer operations from RAM to NAND and vice-versa pretty much all on its own (aside from the CPU instructing it on what to do, and it's possible they have some features in the I/O complex to store a state of instructions that can be triggered through some type of event process), and has the speed necessary to facilitate this, it can stream in needed data very quickly, especially if it is compressed.
The question is if the I/O complex is writing and reading data to/from NAND to/from RAM, do the CPU and/or GPU access data at that moment? Given the PS5's RAM setup, I'm going to say "no", because the I/O complex has to share the bus with the APU given the hUMA memory setup. Unless the I/O complex can write data to a virtualized partition range and the CPU/GPU can access data not in that range while it is reading or writing to that range, but I don't think that is possible without some intermediate hardware. However, it might be why the cache coherency engines are in place: maybe the I/O complex can have its most recent operations checked by the CPU, that way the CPU knows what data might've been updated by the I/O complex while it is operating on a memory range.
While the I/O complex writes to a range, the CPU can take needed data and put it in other locations to make room for more data being written to the partitioned range by the I/O complex. I figure something like that could be done seeing as OSes on computers allocate memory ranges for different programs to contain their contents in; those partitioned ranges for those applications are considered private so that one application doesn't know the contents of the data in the other program's range, though. I'm guessing there's a way they could have the PS5's OS manage a partition range/bank for the I/O Complex to write data to in RAM, and use the cache coherency engines to assist in the CPU knowing if new updated versions of data are in the partition range the I/O complex writes to, that way maybe the CPU can get the updated data from there instead?
I'm actually really curious to see how having the I/O complex write data contents directly to RAM play into any potential bus contention because, again, if the CPU and GPU already have to share the bus (same as with XSX), then I assume another part of the system sending and retrieving data from RAM
also has to share the bus.
As for the XSX, from what it seems like the CPU is using that 1/10th of a single core to write data to/from NAND to/from the RAM, using things like the decompression block along the way if needed. So there's an extra step there compared to PS5, but I'm assuming from there the CPU can write any incoming data from the NAND into either of the two pools of the "split" GDDR6 memory. However, it seems the XSX might have a direct connection between the NAND and GPU for GPU-formatted data, so if the GPU needs any of that type of data it can basically page the 100 GB partition of NAND on the SSD as extended memory (albeit magnitudes slower than GDDR6, but that's just NAND in general tbh).
The fact they already have features on XBO's GPU for executeIndirect (allowing the GPU to perform some limited operations without waiting on the CPU), and the fact they are obviously continuing that with XSX, would suggest they are probably rolling with this setup. Ironically while people like Moore's Law Is Dead did touch on the idea, they did so regarding PS5, not XSX. But from what it seems like the systems are approaching it might be XSX taking this GPU/NAND direct link approach. I guess both systems could do both approaches but that would probably overly complicate the hardware design and not be worth the costs required to cover that much hardware and software functionality.
I'm just speculating based on some actual info and some stuff that can be extrapolated/inferred from that, and some questions on my end about possible design choices that may or may not even be possible. August can't come soon enough xD.
Nope. She says it's too expensive for her. She develops for the Switch, PC and Xbox because of that. As a hobby I might add.
Maybe this will help you further. I'll post every other tweet since you can read two at the same time;
That's quite the gold mine of speculative info tbh x3. Really appreciate this; I got some other speculative details on the SSD I/Os a few days ago and been trying to formulate some thoughts in private. This might help with sorting out some of that stuff I've been sitting on.
I can definitely see the viability to this approach if it's what MS is doing (and there's a decent bit of evidence to suggest it's what they're doing), while there's also a lot of viability to Sony's approach. They're both seemingly doing a lot through some divergent means playing to some historical and market strengths of the respective platform holders.
I am curious to know how is it possible for a college student to get Xbox devkit ?
Same way a single Chinese dude can be developing a game for XSX?
This would not be the first time a young dev got access to then-new console devkit hardware, or devkits to develop on in general. MS probably has some contracts or plans for devs of different financial persuasions.