Is CEN64 planned to be multithreaded?

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Christian010
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Is CEN64 planned to be multithreaded?

Post by Christian010 » Mon Nov 18, 2013 9:56 pm

As far as I have tested this great piece of software I have noticed it runs quite well lots of games considering it is very new and unfinished. But on my Overclocked Core 2 Duo E4500 @ 2.6 GHZ (I know it is pretty old) the emulator runs at about ~20 VI/s, maybe on a faster CPU it will be able to get 60 VI/s.

So… Is CEN64 going to be multithreaded? I don’t know anything of the N64 architecture so I am not sure if this is possible, but if it is, it would greatly impulse the performance of the software. At this time the software only uses 50% of my CPU, so I am assuming it only uses 1 thread.

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MarathonMan
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Re: Is CEN64 planned to be multithreaded?

Post by MarathonMan » Tue Nov 19, 2013 12:38 pm

You can't really multithread a simulator. There's too many dependencies flying around to make it work. I experimented with a "HLE-like" CEN64 before that I could multithread, but wasn't able to get anything other than another couple VI/s out of it (and it wasn't stable, had race conditions, etc.)

I haven't heard of single user that has currently been able to run commercial games at full speed, regardless of their CPU. With time comes optimization. :D

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Christian010
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Re: Is CEN64 planned to be multithreaded?

Post by Christian010 » Tue Nov 19, 2013 3:20 pm

Oh! That is too bad, but it doesn’t really matter, as time passes CPU single thread performance should improve and may be in about 5 or 10 years the top end models from Intel should be able to run games at full speed.

Thanks for the data! :)

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Breadwinka
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Re: Is CEN64 planned to be multithreaded?

Post by Breadwinka » Tue Nov 19, 2013 5:22 pm

Yup with my i5 3570k OC to 4.2ghz I get usually around 40V/I's but can hit 60 during total sequences. Overall the emulator had been getting better and better.

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Nacho
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Re: Is CEN64 planned to be multithreaded?

Post by Nacho » Tue Nov 19, 2013 5:45 pm

Oh... so bad...

In August, you were clearly aiming to a multithread design, as seen on http://board.byuu.org/viewtopic.php?f=8&t=3877

You proposed very clever hacks, and as somebody said there "We need a new way to write emulators". What changed your mind?

Just being curious.

By the way, using a 4.5 GHz computer to simulate a ~0.09GHz system seems so twisted!
Testing CEN64 on: Intel Core i5 520M 2.4 GHz. SSE2 SSE3 SSE4.1 SSE4.2 SSSE3, but no AVX. Ubuntu Linux

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MarathonMan
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Re: Is CEN64 planned to be multithreaded?

Post by MarathonMan » Tue Nov 19, 2013 6:00 pm

Nacho wrote:What changed your mind?
For the time being: just a lack of progress. I tried implementing a whole slew of ideas and nothing really seemed to ever work out. Rollbacks were either too expensive due to the excessive amount of data replication, or too inefficient processing timewise when trying to "undo" old operations.

I also never took Turbo Boost/Turbo Core into consideration. When I was multi-threading things, I found that even when I had some success with multi-threading, it would result in slower overall execution due to the cores running at slower frequencies since multiple cores were active, instead of just one. It's hard enough to get multi-threading to show a benefit, and it's even harder when your per-thread performance is degraded while doing so.

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Nacho
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Re: Is CEN64 planned to be multithreaded?

Post by Nacho » Tue Nov 19, 2013 6:24 pm

well, time to upgrade my CPU, then :P
Testing CEN64 on: Intel Core i5 520M 2.4 GHz. SSE2 SSE3 SSE4.1 SSE4.2 SSSE3, but no AVX. Ubuntu Linux

beannaich
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Re: Is CEN64 planned to be multithreaded?

Post by beannaich » Wed Nov 20, 2013 4:12 pm

Nacho wrote:By the way, using a 4.5 GHz computer to simulate a ~0.09GHz system seems so twisted!
0.09375 GHz + 0.0625 GHz = 0.15625 GHz :)

Not to mention all the synchronizations, data transfers, software rasterization etc that has to happen to make it all work. I'm actually surprised CEN64 runs as fast as it does consider all it has to do.

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Patashu
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Re: Is CEN64 planned to be multithreaded?

Post by Patashu » Wed Nov 20, 2013 7:49 pm

Nacho wrote: By the way, using a 4.5 GHz computer to simulate a ~0.09GHz system seems so twisted!
Wait until you see bsnes, then, which is about as CPU-intensive for an even older console ;)
(The reason why is, bsnes emulates scanlines being progressively drawn while each CPU cycle advances, and cuts no corners anywhere.)

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