MAME and SMP???

[Cisco Kid]

Is there any version of MAME that supports SMP (aka ... dual processors)

Just wondering ... its a thought I had go through my head

Just seems like an easy way to solve the ol' fps problem with some of the newer power hungry ROMs   (I imagine you could actually get a full frame rate with War Gods that way ... lol  ... couple of 2.4Ghz Xeons on a i860 chipset would be freakin sweet if MAME supports it  

[DaveMMR]

War Gods?!  That game doesn't deserve a good framerate!    I'm just kidding --  it wasn't all that bad.  Well... eh...  

But that'd be sweet if they did have SMP support.  The cost of two processors would be slightly offset by the cost of Linux (free).  Of course you can also have Windows XP Professional on the machine, but who wants to pay for that for a MAME cab?    

[JMDickson]

Advance MAME supports SMP in Linux/Mac, but only by offloading screen updates to a second thread.  It was discussed by the developers a couple of years ago, but the consensous was not many could use it, and it was likely to cause performance issues on single CPU systems.  Also, no one felt like doing all that work at the time.

[Cisco Kid]

Of course you can also have Windows XP Professional on the machine, but who wants to pay for that for a MAME cab?    

hehe ... thats free too   (hmmm ... maybe I shouldn't have said that   )

[u_rebelscum]

Hardest thing about SMP and emulation is timing.  The original arcade games expected stuff to occur at a certain rate and order.  With SMP (or any multi-threading) mame would either:

a) Need a lot more time/event checking (besides moving to multi-threading in the first place). ie: add a bunch of complicated overhead, and sometimes stuff would have to wait for something else to finish to keep the emulation "true" (and keep it from crashing in many cases), which would "lose" much (most?, all?) of the speedups of SMP

or

b) Keep all emulation on one thread with the other stuff (UI, input poling, video output, etc) on the other thread(s) (which wouldn't be Symmetrical of SMP).  With most of the slowdown occuring in the emulation part anyway, the speedup wouldn't be all that much.  As said earlier, AdvanceMame has some of this type multithreading.

[shrug]  Nobody is stopping you from trying to add it, though.