Sound auto switching degrades WinUAE performance with shaders enabled

[Leandro Jardim]

Hi Toni,

I've tested with beta 3 that when I play a game and WinUAE turn off the sound after the idle time when the sound stops playing, the CPU meter goes to 97 - 101%.

Even when WinUAE turns on the sound again, the CPU meter fluctuates a lot between 57 - 97%.

When I disable sound auto switching the CPU meter stays at 57% (with shaders enabled). This should be OK, I think.

I'm using WASAPI, so I can't detect exactly when WinUAE turns off the sound, but the time it takes to start slowing down the WinUAE performance is very close to the time the DirectSound driver takes to turning off the sound.

So it's just a guess of what the problem might be...

I didn't posted this possible bug report in the beta 3 thread because I was not sure if my problem was present in the 4.1.0 version or/and was dependent of some other feature of beta 3, since my configuration uses the shader resolution detection and the Y scaling multiplier, present only in this version.

Sorry if that is a specific problem for version 4.2.0. In the previous version it seemed very fast, although it may be also because it doesn't have the extra overhead of the features that I was using.

[Toni Wilen]

Are you sure it isn't simple emulator waiting for sound and when sound is off, it does not need to wait anything and runs faster = uses more CPU. (and don't trust the CPU% too much..)

[Leandro Jardim]

Originally Posted by Toni Wilen

Are you sure it isn't simple emulator waiting for sound and when sound is off, it does not need to wait anything and runs faster = uses more CPU. (and don't trust the CPU% too much..)

No Toni, when sound is permanently on, it runs faster! It runs faster by disabling "automatic switching" in WinUAE sound panel.

When I disable that option, the FPS is always at 50, the sound is clean and the CPU meter is low.

I love browsing the Internet with IBrowse in HiRes 256 colors, with the trinitron shader and with HippoPlayer playing music in the background. My configuration is an A1200 with 28 MHz (full cycle exact). When I disable that specific option above, WinUAE can do it.

I like doing other things as well, but it took me a long time to optimize my settings for everything and used the IBrowse scenario to tweak them.

I love to remember having an A500 in the past, wanting to get the Kickstart 3.1 ROMs, a 28.8 Kbps modem and a TCP stack for my computer, for browsing the Internet with AMosaic. It's nostalgia.

EDIT: The performance of the A1200 IBrowse configuration I cited here oscillates in the same way as with the simple A500 configuration I attached in the first post.

[Toni Wilen]

There is no way that option makes any CPU power difference, at least when audio is playing.

Only possible side-effect is that when audio is switched off due to auto switching, actual Windows audio playback is not stopped, it keeps playing empty samples. It is required to get seamless (no pops or other glitches) audio re-activation.

[Leandro Jardim]

Sorry for this false positive, Toni.

I started this topic only because I was absolutely sure of what was happening!

But I also realized that emulation has improved a lot since I installed a new graphics driver in Windows. Maybe the problem was caused by an "overload" in the old driver.

Thank you so much for looking what was causing that.