PPC Slower

[mritter0]

I am using beta 16 and latest plugins (32bit, even though I have 64bit) for OS4.1FE. I have noticed that it is significantly slower at everything, even booting. I am also getting random crashes (GCC while compiling) of the system, not WinUAE so I have no logs.

I went back and tried the previous 4 betas, same slower speed. I overwrote the old plugins/qemu-uae.dll so I can't really verify it. Could you post/upload the previous version so I can test it?

[Toni Wilen]

Lets first test if last known working qemu version compiled with latest compiler environment has same problem to confirm if problem is qemu or something else.

Need few days or so..

[FrodeSolheim]

@mritter0 Please test with the following (32-bit) qemu-uae.dll: http://fs-uae.net/files/qemu-uae.dll (Static .dll compiled from the qemu-2.2-uae branch)

[mritter0]

That is better on my computer at work. I will try it on my main home computer tonight or tomorrow.

You can really see it in the AmigaOS4.1FE logo fade-in when booting. The version you just posted is a little smoother/quicker, less jerky. The one released with b16 you can really see it stepping through each brighter color change.

The crashes when compiling with GCC is really annoying. 80000003 gurus.

I will post a better report soon.

Thank you.

[mritter0]

Yes. On my main computer it is back to "normal" speed. GCC hasn't crashed. Much better.

[Toni Wilen]

Ok, it is confirmed that some recent QEMU update is the cause.

I think the best option (for now) is to build 64-bit version of 2.2 (including Windows 64-bit fix), finding the real problem is not that important

[Toni Wilen]

Just wondering..

Perhaps this problem is related to BPPC PPC CPU model always running slower (reason unknown, only QEMU config difference is CPU model) than CSPPC PPC CPU model.

If you switch to BPPC config and use 2.2 DLL, do you get same slow speed and crashes when using CSPPC and new DLL? (or use CSPPC config but force CPU model to BPPC using manual config entry ppc_model=603ev)

Also testing with some much newer (but compatible) PPC CPU variant may show some differences. Not sure which model yet.. It is quite possible that QEMU developers don't use or test very old PPC CPU models.

[FrodeSolheim]

I have backported the x86-64 fix to the QEMU 2.2 branch, here is the result:
http://fs-uae.net/files/x86-64/qemu-uae.dll

(Spoiler: it appears to work )

Anyone (mritter0?) care to run this DLL with the 64-bit version of WinUAE and check that the performance is comparable to the 32-bit version?

[Toni Wilen]

Originally Posted by mritter0

I have noticed that it is significantly slower at everything, even booting

How big is the difference when timed with a stop watch? For example time from boot logo screen opening to when WB screen opens. (I get about 17s. This with new i7 Skylake @ 4.5GHz setup)

I can't see any noticeable difference in boot speed between versions (new or old or 32-bit/64-bit).

My next test would be to increase size of QEMU translation cache from 32M to something like 256M, just to see if it changes anything.

(I still not have working mingw environment ready after hardware and everything update)

[mritter0]

Using beta17 for both tests.

With the qemu package from beta16:

Time to boot to WB logo background appears:
32bit: 47 seconds
64bit: 44 seconds

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

With the newest .dll's from Frode:

Time to boot to WB logo background appears:
32bit: 37 seconds
64bit: 36 seconds

No GCC crashes. Doesn't seem "bogged down, sluggish" like the b16 qemu is. Everything is faster.

[FrodeSolheim]

I haven't tested much myself, but it sounds like the conclusion is to use the 2.2-branch for now, and re-version these (with the Windows x86-fix) as the latest plugin version.