GroovyMame Slows Down

[lettuce]

Have noticed that GM will slow down to 66% for no apparent reason and the a minute later go back to 100%. I have attached a log file any ideas??

[Calamity]

Are you using -frame_delay?

BTW, what about this?: http://forum.arcadecontrols.com/index.php/topic,137042.0.html

[lettuce]

No, Frame Delay is disabled

Regarding the other problem i uninstalled and installed the latest drivers for my GFX card and the problem went away

[Sledge]

while on the subject of frame delay..
What's best practice?
Have it turned on globally? or only for games that need it?

[lettuce]

Any ideas?

[Calamity]

Hi lettuce,

So when it slows down you only see the percentage going down or you notice it in game play/sound etc.?

[lettuce]

Yeah the game and audio slow right down, as if its going in slow motion

[Calamity]

Well that's quite odd. Is this a general problem with all games? Maybe there's some background process that could be stealing CPU from us? I'd start task manager so you can monitor your CPU cores work load.

[lettuce]

Well here the odd thing, if i Alt TAB out of MAME when its going slow and Alt TAB back into MAME then its runs fine again

[Calamity]

while on the subject of frame delay..
What's best practice?
Have it turned on globally? or only for games that need it?

I'd recommend adding this option game by game. This is actually not an option for the average user, it's quite experimental, it's better to understand how it actually works if you're using it. That's why it's disabled by default.

[Calamity]

Well here the odd thing, if i Alt TAB out of MAME when its going slow and Alt TAB back into MAME then its runs fine again

I've never seen anything like that...

Did you check the task manager?

[Sledge]

while on the subject of frame delay..
What's best practice?
Have it turned on globally? or only for games that need it?

I'd recommend adding this option game by game. This is actually not an option for the average user, it's quite experimental, it's better to understand how it actually works if you're using it. That's why it's disabled by default.

is there a way to have it enable only for interlaced games?
maybe interlaced.ini or something?

[lettuce]

Well here the odd thing, if i Alt TAB out of MAME when its going slow and Alt TAB back into MAME then its runs fine again

I've never seen anything like that...

Did you check the task manager?

As soon as I alt + tab out of GM I can hear the audio run at stupidly fast speed, it just seems if you get out of zgM then the problem stops

[Calamity]

As soon as I alt + tab out of GM I can hear the audio run at stupidly fast speed, it just seems if you get out of zgM then the problem stops

That's irrelevant, you're just dettaching MAME from v-sync so it goes crazy fast. As I said, you need to check in task manager for CPU issues. Something must be sucking your CPU, any antivirus?

[lettuce]

Heres a vid showing the problem Calamity and also shows the task manager...

http://www.youtube.com/watch?v=fx0jxX7NRhs&feature=youtu.be

There appears to be no other pogram knicking cpu cycles at all, infact GM is only using 18% CPU power.

Odd think i have noticed that one time it was doing this, i hit the Print Screen button and as soon as i did that the game speed up back to normal speed....very odd!

[Calamity]

It says 'private video'.

[lettuce]

Ah sorry, try now

[Calamity]

I wonder if the problem exists with hlsl off.

[lettuce]

I can try, doesn't happen all the time however. What is your thinking behind HLSL causing the issue?

[Calamity]

I was thinking it could be due to GPU overheating, caused by HLSL intensive rendering.

[lettuce]

Nah i doubt that very much, i have a after market cooler on my GPU and even playing games like Crysis 3 on high setting the temp never goes above 52c. But if that was the cause what would explain why when i pressed 'print screen' did it stop it and go back to the correct speed??

[Calamity]

You have only three possible sources of slow down:

- CPU not capable (discarded)
- GPU not capable (discarded)
- Badly reported vsync signals. Missing one out of three retraces will cause GM run at 66% (exactly what your seeing). Vsync has worked flawlessly all this time and nothing relevant has been changed lately so I suspect about your video drivers.

[lettuce]

Its definitely related to HLSL. I disabled HSLS and didn't get a single slow down. So the question is why is HLSL settings causing this issue?

[Calamity]

Its definitely related to HLSL. I disabled HSLS and didn't get a single slow down. So the question is why is HLSL settings causing this issue?

Because at some point the GPU is overloaded so that one out of three frames takes more than 16.67 ms to get rendered, so its corresponding retrace signal is missed, and it has to wait for the next one. This issue would be masked if you run with vsync off, as the average speed would still be 100%. But vsync requires that every single frame is rendered within its time slice.

[lettuce]

Hmm well i have a Nvidia 7970 3GB, i would think that card would be more than capable of running HLSL......well infact i know it is as i have never had this problem before and have only noticed it in 0.152

[Calamity]

I'm not saying your card is not capable, indeed it shouldn't necessarily be a GPU problem. But for me, it is crystal clear that the issue is that for 1 out of 3 frames, this is what happens:

CPU time + GPU time > 16.67 ms

Of course if you use HLSL, then GPU time is bigger, so it's more likely you'll see the problem.

Trust me on this, there's no black magic here.

So why would you see this problem with 0.152 and not before? They change stuff in MAME all the time, maybe now that driver eats more CPU, maybe HLSL now eats more GPU... But I know the stuff I touch for the GM patch and I'm 99.9% sure the problem is not GM related.

PD: BTW, try if enabling multithreading makes any difference.