JIT problem (4.9.0+)

[Ponki1986]

I've decided to upload a picture of the JIT message here as it may prove useful. I have encountered a similar situation in this thread before. As recommended, I have set with StackAttack2 an even bigger stack than the author recommends. In contrast, now the error message showed up when I started SnoopDOS and enabled logging. I then started Voodoo-X for archiving and wanted to check if it was missing something, because when I unzip something the progress window is empty. Unfortunately while running Voodoo-X that SnoopDOS in the background everything crashed.

[Toni Wilen]

Originally Posted by Ponki1986

I am sorry to return to the topic of JIT again. I don't know how to prove that since version 4.9 of WinUAE JIT works worse. When I previously used 4.2.1 or 4.4 all the games and programs I own worked fine. I never saw the JIT message window. I could re-share the logs, configuration file, dmp files or screenshots of the JIT message, but I doubt it would help. I could also make a long video showing that under 4.2.1 or 4.4 everything works fine and from 4.9 onwards the problems start, but will that help? As instructed I have increased the stack for the programs that started causing problems, but this does not help. I have reduced the size of the Z3 Fast memory, reduced the RTG memory but this does not help. Yes I can disable the JIT, but that won't give me the performance I want.

If it happens before 4.9.2 betas: this was wrong thread (and too late..) If true, I'll move these posts because non-beta related posts should not be in beta thread and also beta thread closes soon..

If you really can duplicate it easily: remove everything unnecessary from your config (minimal ram size, only chip ram + mainboard or Z3 fast only, all unneeded harddrives, all unneeded expansions, even RTG). Preferably boot without startup-sequence. Make sure none of CPU compatibility options are ticked (for example no more compatible, no speed adjustments, fastest possible only)

First test is to try with JIT enabled but Direct disabled.

Then check if it still happens. If it does: find to find exact beta that introduced it (start from 4.9.0 first beta, links should be still valid). If it does not: it must be something that was removed from config. Try to find which one. The less moving part, the better. Some expansion can work strangely with JIT.

JIT is difficult to debug and really annoying to debug (x86 disassembly sucks and debugging it sucks even more)

Still wondering why one else has reported this.. (Which usually points to some specific configuration or weird software)

EDIT: original post disappeared?

[Ponki1986]

I apologise for inserting my comment and then deleting it in a moment in the hope that no one had time to read it. I have come to the conclusion that it makes no sense.

I'll try to find the cause in my AmigaOS and WinUAE configuration instead of wasting your time.

Thank you for your time and dedication.

[Toni Wilen]

Moved.

It still can be a UAE bug. It is just very difficult to find/confirm without removing unknown variables.

[Ponki1986]

After a long break I am back with the topic of JIT. First the issue of performance degradation, which I reported in the topic about Beta 4.9.9 (4.10). I spent a lot of time to test all the official versions of WinUAE from 4.0 to 4.10. I also used 4.9.9 B5 in the test, because it was the only one of the available beta versions that had a small performance increase before 4.10 was released.

JIT performance test procedure.

- Booting the computer after first completely disconnecting the power supply.

- Windows 7 starts, but instead of the Explorer shell, WinUAE starts with the indicated configuration.

- After loading Workbench, waiting about 1 minute until NewMeter shows the occupancy of the emulated CPU at 0-1%.

- Running SysInfo 4.4. 3 times to measure the speed.

- Running AIBB 6.5. 3 times measuring Dhrystones, code type 68000.

-Running in Shell 3 times measurement with SortBench 1.1.

- Running AmiQuake 1.35 from NovaCoder. Start 3 times in console: timedemo demo1.dem. RTG graphic mode UAEGFX 640x480.

- Start script running DGen 1.33 SDL emulator 3 times in full screen, with Street of Rage 2 rom. Timed performance measurement from startup, until the demo loops when the Sega startup logo appears again.

- Shutting down WinUAE with the UAEQuit command.

Unfortunately, the Beta version didn't do all the work, causing the GURU to be displayed when DGen starts up. Of course, it could be argued that a malfunctioning DGen is to blame for the error, but other versions of WinUAE had no problems with it.

I checked my AmigaOS, games and programs to find those causing JIT errors. Yes I did find a few that hung AmigaOS using older versions of WinUAE, and from 4.9 onwards additionally caused a JIT message window to open. Everything else works fine without the need to increase the stack for the CPU.

I currently use version 4.4 if I need more performance, if I need to use FloppyBridge I switch to 4.10. The problem with Overlay/PIP in 4.4 I of course solved again with Windows XP compatibility mode, without the possibility to use DirectX 11.

I also found a situation where version 4.10 is clearly faster than 4.4 even though the measurement results showed otherwise. For example, I ran the emulator VICE C64 2.1. Under WinUAE 4.4 C64 games stutter, under 4.10 they run smoothly.

I attach the dump files, generated mainly by versions 4.9.9 and 4.10. In addition, log files of all versions, my configuration, my Startup-Sequence and User-Startup, and a list of WBStartup contents. And most importantly, a table of measurement results, which clearly shows that 4.4 was the fastest version of WinUAE.

The computer I ran the tests on was a Fujitsu Fur S720 with an AMD GX-217GA 1.65 GHz and Windows 7 x86 SP1.

PS. If something is incomprehensible it will probably be the fault of DeepL.

WinUAE Speed Comparison
WinUAE Debug Files

[Toni Wilen]

Thanks. And good test cases too

Does JIT cache size affect anything? One known problem (which I already probably mentioned) is that older CPUs have smaller L2/L3 caches which combined with large JIT cache can make a big difference if JIT cache is too large and larger WinUAE code takes more space.

Was RTG mode active when testing?

[Ponki1986]

I haven't tried changing the JIT cache, I didn't know that could have an effect. Thanks for the tips, I'll check it out. In terms of RTG, yes he has always been active. For example, when I started AIBB, Workbench was open in the background in RTG mode.

EDIT: I checked the JIT cache settings by reducing the amount of cache. I currently have it set to 16 MB and for the time demo example in Quake at this size, the average FPS was 21.7. When I started to reduce this setting automatically the amount of FPS also started to slightly decrease. With a cache of 8 MB I got an average of 21.4 FPS, with 2 MB it was 21 FPS. With a setting of 1 MB, the FPS result was 16.4.