Quad-Core Processing

[Xtreme2damax]

*Facepalm*

This has been discussed many times before, Dolphin will never have quad core support, there is nothing to be gained from it. One core already handles the cpu emulation and a second core handles the gpu emulation. There is a possibility that Dolphin will support a third core in the future for LLE sound emulation, but nothing further than that.

There is nothing else that can be split onto separate cores other than what was already mentioned above. Trying to do so would make syncing the various functions of the emulator a nightmare, create major stability problems, and would likely make performance worse rather than better. Not to mention that it is most likely not possible nor is it feasible, the Wii/GC isn't even a multi-core system to begin with. Multi-Core processors would likely be more useful when PS3 and Xbox 360 emulation finally becomes a reality and is possible, but until then anything more than dual core is essentially useless for emulation. PCSX2 and Dolphin seem to be the only emulators that take advantage of dual core processors, as far as I know Dreamcast, PS1, handheld emulators only run in single core mode.

[skid]

Yeh, I've attempted to add multi-core support to Dolphin twice now.

The first time was to make the FIFO data transfer multi-threaded. In my tests, the FPS tripled. After committing it to trunk, the feedback was that this caused a lot of glitches and I pulled the patch out.

The second time, I tried to multi-thread the CPU core. I got half way and found that this required a lot of work to complete. Dolphin was not designed to be multi-threaded and has a lot of assumptions, in the code, that it would run on one core only. Early tests indicated that the performance improvement would be negligible and I shelved the project.

[Xtreme2damax]

Couldn't the issues with multi-core fifo been fixed though? I never really tested that, kind of late now considering that there has been quite a bit of changes to the fifo since then and it would be a pain to piece back in. I don't really feel like using an older revision, I probably wouldn't have better performance with my Core2duo anyway, so not much point.

Would be nice to see better performance with Dolphin, would make testing games much easier.

[skid]

Yeh, the multi-threaded FIFO was a complicated one because of how Dolphin has FPS and VPS. So when I said that the game runs faster because of the multi-threaded FIFO, i am referring to the FPS only. But the game as a whole did not triple in speed. The game just ran smoother (triple the FPS) which was verified by some of the testers. By looking at the numbers on the screen, we couldn't tell that the game was going any faster.

For example, if we were playing a game of Mario Kart Wii, where the timer was moving at half speed, the patch would not have sped up the timer. However, the animation would have been smoother during the race.

Hope I explained that clearly.

[thaCASHdude]

yep, as clear as a whistle

[Xtreme2damax]

Thanks for explaining skid, so it was nothing more than an artificial increase in speed while game speed basically remained the same?

[j2844504]

On one machine i have a q6600 (quad core) running at 2.4ghz 3 gigs of ram and an 8800gt. On my laptop I have a p8700 (dual core) running at 2.8ghz with 6 gigs of ram and a gtx 260m. Both machines running windows 7 64 bit and the graphics cards are very similar. The quad does have a slightly better frame rate than the dual with dolphin. Seems the quad always seems to run things slightly faster than the dual.

[boogerlad]

well fps is always what's limiting my speed. I like smooth.

[shawnanastasio]

the reason dolphin runs better on the quad core is because the quad core's 2 cores that dolphin uses are better than the other computers cores. also graphics cards make a HUGE inpact on preformance

[Xtreme2damax]

(06-17-2010, 05:49 AM)j2844504 Wrote: On one machine i have a q6600 (quad core) running at 2.4ghz 3 gigs of ram and an 8800gt. On my laptop I have a p8700 (dual core) running at 2.8ghz with 6 gigs of ram and a gtx 260m. Both machines running windows 7 64 bit and the graphics cards are very similar. The quad does have a slightly better frame rate than the dual with dolphin. Seems the quad always seems to run things slightly faster than the dual.

That's because system processes are offloaded onto the other two cores, leaving more cpu for Dolphin to use. On dual core, Dolphin needs to share more of the cpu with the system processes thus decreasing smoothness and performance.