1ghz pandora dreamcast emulation

[Exophase]

I'm sure if you want to look at it completely relatively then anything can look good in some context. I don't think any of that justifies a claim that it "ran pretty well" without more information.

 

[Wrath Of Khan]

I'm sure if you want to look at it completely relatively then anything can look good in some context. I don't think any of that justifies a claim that it "ran pretty well" without more information.

Would some of the less intensive games run better.Perhaps non 3d ones etc? It looks like there is some potential in the video for improvements imo.

 

[Exophase]

Would some of the less intensive games run better.Perhaps non 3d ones etc? It looks like there is some potential in the video for improvements imo.

I don't know. How complex or visually intensive a game looks doesn't always correlate well with how demanding it is to emulate it. If you want an idea maybe you should try running nullDC on your computer and look at what the CPU utilization is like for different games.


But until drk||Raziel or someone else actually releases a Dreamcast emulator for Pandora this is all moot. And how much it can be improved isn't something that can really be easily ascertained, especially by someone who isn't programming it.

 

[Wrath Of Khan]

Would some of the less intensive games run better.Perhaps non 3d ones etc? It looks like there is some potential in the video for improvements imo.

I don't know. How complex or visually intensive a game looks doesn't always correlate well with how demanding it is to emulate it. If you want an idea maybe you should try running nullDC on your computer and look at what the CPU utilization is like for different games.


But until drk||Raziel or someone else actually releases a Dreamcast emulator for Pandora this is all moot. And how much it can be improved isn't something that can really be easily ascertained, especially by someone who isn't programming it.

Ah ok i see.

 

[peacelovefleshbones]

If you are genuinely wondering why few people reply to this, read How To Ask Questions The Smart Way

saved.

 

[anexanhume]

Drkraziel behind null dc had a crack at dreamcast emulation for phones and released a few proof of concept videos that can be found on youtube, however he has dropped of the radar about 2 years ago and decided released the source for null dc but not for the work he had done for phones. so no one can continue the progress he had made its a case of starting from scratch again, if anyone fancied/has already picked up the challenge as far as i am aware

Must be what Ari64 has been doing lately

 

[Exophase]

Must be what Ari64 has been doing lately

Since Ari64 voiced some serious doubts about the viability of Dreamcast emulation on Pandora I'd be kind of surprised..


Although he did already do an SH2 dynarec for Saturn.

 

[anexanhume]

Must be what Ari64 has been doing lately

Since Ari64 voiced some serious doubts about the viability of Dreamcast emulation on Pandora I'd be kind of surprised..


Although he did already do an SH2 dynarec for Saturn.

That was kind of my point. Ari64 seems to be do all of the impossible. But of course it was in jest. I doubt the work a DC emulator would take, especially without Iziel's ARM work to leverage, is just not worth it for what would be a proof of concept on a pandora type SoC. From what we've seen of DC emulation, I would expect it to require Krait or an A15 based SoC to begin thinking about playable for any game.

 

[drkIIRaziel]

Popping out of nowhere (well, you can thank sepp256 actually ..) I can give some perfomance numbers. Based on my previus perfomance evaluation with A8, the current speed on A9, and speed of a recent build on my (500 mhz?) pandora i'd say around 80%. A HUGE bootleneck is the SGX (drivers) and another major problem on A8 is softfp calling (this is fixable by updating linux/drivers though).


There are some hoops I still have to go throught before beeing able to make a release (and its quite messy currently), so don't take this as a promise or anything.

 

[mcobit]

Nice to hear from you!


So you are saying that you habe 80% at 500 mhz?


Well, as the sgx is the bottleneck, more cpuspeed won't do much, would it?

 

[drkIIRaziel]

80% at 1Ghz (with sound). I'll try to update the pandora libs to see perfm. (i updated OS, and angstrom has wayy too old std libs ..).


The SGX driver loves to eat cpu time, doing ... no idea what exactly. CPU is always a bottleneck, as is poor cache perfomance and low (effective) bandwidth to ram. But hey, thats what gets you into low power


Since nothing beats real numbers ...


@ 800 mhz


bios main menu: 101%


recv ingame: 74, intro 65~70, with HEAVY freamskipping (SGX was at around 7 fps out of 18 or so -- the game runs at 25 normally).


Recv is one of the fast games (and happyly gets into tripple digits with A9 at similar clock).

 

[Mr_Loon]

80% at 1Ghz (with sound)

That sounds very promising for a Pandora 1.5 overclocked to 1.2Ghz then.


Reckon Dreamcast emulation will shift quite a few units.

 

[WizardStan]

i updated OS, and angstrom has wayy too old std libs .

Even the SuperZaxxon running 3.2?

 

[mcobit]

That only has a newer kernel, not newer libs

 

[ingoreis]

i dont know that it help,but try a faaast usb stick.


For Qemu was this a little Speedup in loading Times


Nice to hear that you work again on it

 

[Wrath Of Khan]

Popping out of nowhere (well, you can thank sepp256 actually ..) I can give some perfomance numbers. Based on my previus perfomance evaluation with A8, the current speed on A9, and speed of a recent build on my (500 mhz?) pandora i'd say around 80%. A HUGE bootleneck is the SGX (drivers) and another major problem on A8 is softfp calling (this is fixable by updating linux/drivers though).


There are some hoops I still have to go throught before beeing able to make a release (and its quite messy currently), so don't take this as a promise or anything.

Craig might donate a 1ghz pandora to you for this emulator.I pm'd him a week ago about this and he was game.Me and Zuk also offer a bounty of 300 euros and 200 dollars also zuk is willing to pay for a 1ghz pandora for you to get this emu running on the 1ghz pandora.There is loads of interest in dreamcast emulation from users here on the forums.What do you think?

 

[WizardStan]

That only has a newer kernel, not newer libs

It does have a newer SGX driver, at least, which might reduce parts of the problem.

 

[anexanhume]

This thread just got really exciting.

 

[Wrath Of Khan]

^^^^^Hell Yeah.

 

[Exophase]

Craig might donate a 1ghz pandora to you for this emulator.I pm'd him a week ago about this and he was game.Me and Zuk also offer a bounty of 300 euros and 200 dollars also zuk is willing to pay for a 1ghz pandora for you to get this emu running on the 1ghz pandora.There is loads of interest in dreamcast emulation from users here on the forums.What do you think?

Dude, he already has a Pandora. He doesn't need a new one. I don't think you are understanding that you don't need a 1GHz Pandora to develop software that works on it. It runs the SAME SOFTWARE.

80% at 1Ghz (with sound). I'll try to update the pandora libs to see perfm. (i updated OS, and angstrom has wayy too old std libs ..).


The SGX driver loves to eat cpu time, doing ... no idea what exactly. CPU is always a bottleneck, as is poor cache perfomance and low (effective) bandwidth to ram. But hey, thats what gets you into low power


Since nothing beats real numbers ...


@ 800 mhz


bios main menu: 101%


recv ingame: 74, intro 65~70, with HEAVY freamskipping (SGX was at around 7 fps out of 18 or so -- the game runs at 25 normally).


Recv is one of the fast games (and happyly gets into tripple digits with A9 at similar clock).

This is interesting, and seems like a big improvement over the performance in MWeston's video which ran at about 40% realtime with no audio, at 800MHz. But you say this is one of the less demanding games, so I guess people should take this as a best case.


I'd love to hear more information, of course. I have some specific questions like usual..


1) How are you handling emulated instructions/second these days? Is there some timing depending on instruction type or a fixed number? Are you adjusting it based on game? If so is this done manually, stored in profiles, or what? Is there idle loop detection or some variability based on hardware sleep?


2) You say there's a lot of frameskip in your test, and seem to be implying that it's determined automatically. Since you aren't reaching real time speed with it, what is your cutoff exactly? Is it being driven by lack of CPU time or lack of GPU time? If it's the latter, is it a matter of preparing the display list then not sending it if the last display list is still being rendered? The 1GHz Pandoras have a 200MHz SGX so it should render a lot more quickly.


3) You seem to think softfp is a big performance limiter. That should only be the case if you're calling a lot of C (or some other high-level) functions with float return values (there's a little bit of a penalty for float parameters but it's not nearly as bad). Are you calling these functions frequently from recompiled code? If so, it seems like you'd gain a lot more from writing the functions in ASM than from hardfp alone, since you'd get a lot more control over the ABI overall..