Strange CPU usage under Wine

[mark_k]

This kind of follows on from a posting in the WinUAE 2.7 beta thread.

I noticed something strange with WinUAE CPU usage testing under Wine/Linux (with Nvidia binary driver). Can any other Wine users reproduce this?

With native chipset modes and D3D, triple buffering, no scaling, no vsync, CPU usage is inversely proportional to window size! The larger the window, the lower the CPU usage. Which seems very strange. With no buffering or double buffering however, CPU usage is proportional to window size.

With DirectDraw on the other hand, CPU usage is proportional to window size.

I tested various settings, using the "top" command in Linux to see the CPU usage of the WinUAE process.

Native chipset (PAL 640x560 Workbench), Direct3D, triple buffering, null filter, no scaling
Window a little larger than the Workbench screen: 71-72% CPU
Window maximised: 34% CPU

With DirectDraw the opposite is true, e.g. 73-74% with smaller window vs 91% CPU with window maximised.

RTG modes are different. With uaegfx:

uaegfx 640x480 (window a little larger), D3D, triple buffering: 69% CPU
With maximised window: 76-77% CPU
1024x768 Workbench with maximised window: 77-79% CPU
1024x768 Workbench, DirectDraw, maximised window: 69% CPU
640x480 WB, DirectDraw, smaller window: 69% CPU

Finally Cirrus RTG (Piccolo):
DirectDraw, 640x480 WB and small or maximised window, and 1024x768 WB with maximised window: all 69% CPU
D3D 1024x768 WB, maximised window: 89% CPU. Same WB with window a little larger than the WB screen: 81% CPU.
Same window size but 640x480 Workbench: 80% CPU
640x480 WB with similar window size: 70% CPU