General

[Drakon_PL]

Hey, i was doing some testing on Vita with sdk and i noticed that i couldn't get more that ~0.034 ms per frame, with is about 30 fps.

Is it possible to change that limit or i'm just doing something wrong?

[Drakon_PL]

I will answer on my own question:

PS Vita have 60 fps lock.

I used font code example from BallMazeDemo, with turned really bad in performance on Vita (demo running painfully slow on device) .

[SSJSubgeta]

Thanks for the feedback on your findings.
Just a quick questions from your experience; Is it better to run games/apps 30fps or 60fps on Vita?

Maybe if an official dev can come in and provide more insight on this, it would be appreciated.

[Sappharad]

In my own tests of some CPU heavy code, I've found that the performance is absolutely awful.

Running a C# version of some C++ code, I found the performace (in terms of amount of code executed) to be similar to Pentium running at 66mhz. I can give some more detailed statistics if anyone is interested.

In short, the PSSuite doesn't seem to be targeted towards applications that use a lot of CPU power. You're going to be stuck with some very simple games and apps on the Vita, unless they plan to improve their Mono VM.

[MDaveUK]

Sappharad, does you CPU heavy code use a lot of math? Or is it more things like for loops and such, that you have a lot of?

[Sappharad]

Disclaimer: The following almost certainly violates the EULA and doesn't represent something that I intend to release. It is only a performance test.

Okay, here are some hard numbers. The CPU heavy code that I tested is a port of a 68000 CPU emulator. (More specifically, emulation of some hardware that uses that processor, but with other chips like the Z80 completely disabled. Input was not implemented, and basic video output is handled in which I copy the simulated framebuffer into a texture for display) This means lots of looping and lots of basic math.

I measured the time needed to execute the first 229825610 clock cycles on the emulated CPU. This would be the equivalent of 30 seconds realtime (Plus an extra frame, due to a comparsion mistake on my part) of the simulated hardware.

On my test machine (With a single E5462 Harpertown Xeon processor) running the PSSuite simulator in Windows 7 under VMWare Fusion it takes an average of 26801.6819ms to execute the aforementioned number of clock cycles. On the Vita hardware, it takes 351573.936ms to execute the same number of clock cycles. That means it takes the Vita 13.11 times as long to execute the same amount of code.

Now, there are some flaws in this test, namely the overhead of updating the texture and rendering. But when I repeated the test without video output, the difference was only about 12%. I guess the question is, is the 4.5 year old desktop processor in my machine 12 times faster than the Vita's? (Both processors are quad core, but the code is being executed on a single thread) I don't have any benchmarks to compare what the two processors should be capable of, (what if the PSSuite doesn't use a JIT compiler and the PC runtime does?) but a 12x difference actually isn't that bad. It just looks slow watching it in motion.

I hope this helps someone.

[Uncle_NC]

Yes,I also have  a test.

I Try to port a FC simulator.on my 5 years old PC,It is full of 60fps.

On PSV is only 15fps. The GPU is powerful,but CPU likes 66MHZ.

[niwrA]

Perhaps there are no VFP / Neon SIMD optimisations done yet? There should be a lot of room for improvement, but those kind of optimisations are probably difficult, and come when the basic platform is known to be stable?

[MartinCaine]

I agree performance on the Vita doesn't seem to be too great (the Tablet S in my tests seems to be faster but I assume they're all running on the same core VM anyway?

It could indeed be that the core math stuff hasn't been SIMD optimized though I have also noticed huge performance problems when running debug code too. With the debugger attached my code executes a lot slower. These tests should all be made with Release builds to see how fast they really are.

My game Positron is running pretty well at 60fps. While it's not the most graphical nor the most math heavy game it is a full game ported over from XNA.

[wxtry_vita]

i think maybe the problem is in texture binding. in my program, i loaded two textures and bind them to index 0 in two render function and run each of the function more than twice in a circle,this made the performance looks pretty bad. but then i changed my program to load picture from only one texture file and only bind it to the graphic content one time, the performance looks much better now.