@Fab

Wondering that speed difference...Shouldn't SDL only cause a function call overhead and nothing that dramatic (a blit should be a blit). If it does, can't it be optimised? I haven't looked into SDL source lately so don't know what does it do...

I have nothing against "native" ports but if SDL is that much slower, it should be fixed IMHO.

@drHirudo

i tried Cruis'n USA on mos mame port (http://fabportnawak.free.fr/mame/mame-0.120.lha) and got 28-31% speed (g4 1ghz mos 2.1).

@Mr_Capehill

SDL does lots of unoptimized things. Like i said, the time to copy data with SDLMame/Xmame is about 4 times as long as a native routine, which leds to the 30% faster figure i gave earlier. For smaller games, the speedup ratio is even more important. Take something like 1943. With SDLmame/Xmame, you painfully reach 170% speed (blit takes 5ms and rest of emulation 4ms = 9ms per frame. 16/9 ~ 170%), while a port with more optimized blit reaches 300% speed (blit takes 1ms and rest of emulation 4ms = 5ms per frame. 16/5 ~ 320% speed). Whether you can fix this slowness or not in SDL, i don't know. :)

About MAME itself, since 0.107, video system was completely reworked and became even more os independant. They added a generic blitter template pixel/depth-independant, but it has a big issue: it sometimes copies using 16bits words, which is really slow (at least on peg). Copying with 32bits or 64bits to video mem data makes a *big* difference there. So a blind port is clearly not a good idea when dealing with MAME, especially latest versions.

And since 0.125 or so, MAME became about 15-20% slower compared to 0.121. So for A1/Sam targets, i would advise to stop at 0.121 or older (0.121 is already a bit slower than 0.10x and much slower than 0.6x or 0.3x).

@rzookol

For games that are already way too slow, SDL or not probably doesn't matter a lot. For crusnusa, if you get 30% speed, you need about 50ms to process a frame, so 4ms more with a SDL port wouldn't dramatically change FPS at that point. :)

Last edited by Fab on 02-Oct-2008 at 01:09 PM.
Last edited by Fab on 02-Oct-2008 at 01:08 PM.

@samo79

Quote:

samo79 wrote: @Mr_Capehill Yes he is around, but he is also busy with other things, there are also another big problem, he doesn't have (at the moment) any Amiga hardware to develop within, this is the main reason about the slowdown of xMame ... So the actual work are on Linux and some strange and annoying crosscompile

Well, last one was done that way too (cross compile).

anyway if he needs hw, just tell him to email me and i will send him an µa1c.
i lost touch with steffen over 1.5 year ago but i am 100% sure he still knows who i am lol.

So, Samo, can you let him know?

cheers

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@Toaks

This is very kind from you, yes naturally I can contact him. stay tuned

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@Mr_Capehill

Quote:

Are you sure you can't compile with OS 4.1 virtual memory system?

I tried to compile MAME on windows. It ran out of swap space.

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I compile it natively with gcc 2.95, 3.4.6 and also tried 4.2, and i never ran out of my 512MB RAM here (with most optimisations on).

@Fab

With all emulations included? It won't work here, it always runs out of swap space. That's xmame-0.106.

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@Rogue

Yes, i always include all drivers and cpu cores. 0.106 is now quite old and i can't remember i ever compiled this one. But at least, 0.104, 0.113, 0.117, 0.120, 0.121 & 0.126 required less than 512MB, at least on powerpc with gcc3.4.6. But maybe consumption is much higher on win32 depending on their compilation options, I can't tell.

Ah, just noticed you tried xmame. Which file fails then? Some specific xmame source (such as hq3x or some similar filter maybe?), or a generic mame source file?

Last edited by Fab on 03-Oct-2008 at 02:51 PM.

@Fab

It's always linking that fails. The files compile alright, but the linker fails by running out of swap space. I haven't looked at it for a while, I was searching for a way to outsource the emulations into loadable shared objects (which would be way better than having a monolithic binary) but apparently that wasn't possible.

I'm no MAME expert though, I don't even have a ROM to test with

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@Rogue

Mh, interesting. Well xmame 0.106 is really quite old and not maintained anymore. I think i even remember having read about some linking issue at some point. But anyway, I'd suggest compiling SDLmame (or SDLmess). It's cleaner than xmame and should give less trouble.

http://rbelmont.mameworld.info/sdlmame0121.zip for instance.

Last edited by Fab on 03-Oct-2008 at 06:55 PM.

@Rogue

Quote:

Rogue wrote: I'm no MAME expert though, I don't even have a ROM to test with

There are some freely downloadable ROMs on the MAME website here: freeware MAME ROMs

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