nesdev.org

Well, I got progress. Windows 7 is slowing down the emulation by doing stuff in background, like the boring Windows Update. It dropped the frame rate to below 20!

I reduced the audio buffer to half ($800->$400), and changed the sound sample rate from 48000 to 44100Hz (and the internal APU constant for resampling). It worked like a charm. However, as I said, the frame rate drops during the emulation, but got back to 60 soon.

Zepper wrote:What profiler do you suggest for it? (free)

On Windows try gprof. Here's a guide: https://web.eecs.umich.edu/~sugih/point ... quick.html

On Linux use perf. Here's a guide: https://perf.wiki.kernel.org/index.php/Main_Page

Zepper wrote:Well, I got progress. Windows 7 is slowing down the emulation by doing stuff in background, like the boring Windows Update. It dropped the frame rate to below 20!

Sounds like a modern computing horror story about how much less efficient things have become, and how you're supposed to make up the difference with excessive hardware.

Espozo wrote:

Zepper wrote:Well, I got progress. Windows 7 is slowing down the emulation by doing stuff in background, like the boring Windows Update. It dropped the frame rate to below 20!

Sounds like a modern computing horror story about how much less efficient things have become, and how you're supposed to make up the difference with excessive hardware.

If your operating system is using more than 1-2% of CPU in "idle", you've got problems. That's not normal at all.

Well, several of the Windows 7 updates in the past year have been known to be... questionable. It's like a rat's nest at times. Many have re-installed things like telemetry, so you have to figure out which updates do what. I tend to be a month behind on patches for that exact reason: I err on the side of caution. It's saved me a LOT of pain, let me assure you.

Windows Update taking like 9 billion years to "figure out" what all the updates are that should be available to you is actually solved through several "sub-updates". So if you haven't gone through the pain of doing that (installing specific KBs that fix it), that's probably why. If your "Windows Update" scan previously took, say, 15 minutes, these KBs/sub-updates can actually bring that down into the under-a-minute range.

Let me know if you want details. I actually slipstream all of this stuff into my own Windows 7 ISOs so that I don't have to deal with it again. I think I have a list of the KBs and what not in my slipstream.bat.

A great website to start following for stuff like this is https://www.askwoody.com or follow him on Twitter at @woodyleonhard -- he works for ComputerWorld.

And let's not forget with things like Meltdown/Spectre, figuring out used CPU time is way more complicated than it used to be. Worth watching if you care about low-level details, trust me. (And yes, these apply to Windows too)