09057: all games using cedar magnet: high cpu usage and slowdown

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
09057	Speed	Major	Always	21 days ago	13 days ago

Tester	Augusto	View Status	Public	Platform	MAME (Unofficial Binary)
Assigned To		Resolution	No change required	OS	Linux (64-bit)
Status [?]	Closed			Driver	efo/cedar_magnet.cpp
Version	0.271	Fixed in Version		Build	64-bit
		Fixed in Git Commit		Github Pull Request #

Summary	09057: all games using cedar magnet: high cpu usage and slowdown
Description	Hello. Thanks for reading my topic. OS Linux kernel 6.8 Ubuntu 24.04 and CPU AMD FX 6 cores 3500 Mhz The games using cedar_magnet driver are having much slowdown for example mag_xain ( Xain'd Sleena SC 3.0 magnet system) That game use 5x Z80 5 Mhz and not use netlist. The games are simple not having 68k or other better cpus. If using cpu power profile power saver is 24 % speed and profile high performance is 70 % speed. Overclocking all CPUs to 200 % is 45 % speed. Perhaps not is related with Z80 changes. Have an good week and new happy year.
Steps To Reproduce
Additional Information
Github Commit

Flags
Regression Version
Affected Sets / Systems	all games using cedar magnet

Attached Files

No.22725 hap Developer 21 days ago edited on: 21 days ago	Like tokio: expectation, not a bug. Yes, if you say it has 5 Z80, each 5MHz, and I see config.set_perfect_quantum(m_maincpu); in the driver, it's going to be slow.
No.22730 Augusto Tester 21 days ago	Only few games use config.set_perfect_quantum ? tokio are in the list ? Z80 changes not does slowdowns in several others games.
No.22731 hap Developer 21 days ago edited on: 21 days ago	It depends on how many Z80s the hardware has. tokio has 3, and two of them at pretty high clock speed (6MHz), therefore it got pretty taxing to emulate. - when using perfect quantum, that is.
No.22732 Augusto Tester 21 days ago	That is the problem. Bubble Bobble use the same hardware with exact 2 Z80 at 6 MHZ plus YM3526 and not does much slowdown as tokio. The other games using multiple parallel Z80 not having slowdown even using the new Z80 core.
No.22738 Robbbert Moderator 21 days ago	My machine is quite old (i7-8700) and doing a bench run gave 143.63% - running it normally gives a steady 100.00% >mame mag_xain -bench 90 Average speed: 143.63% (89 seconds) So I cannot confirm any problem.
No.22740 hap Developer 20 days ago	He's just saying the driver got slower after the Z80 rewrite. Which is expected.
No.22741 Robbbert Moderator 20 days ago	Oh, yeah, that is expected. So it's not a bug, maybe better discussed on a forum. Augusto unless you can prove a bug, I'm going to close this.
No.22745 Augusto Tester 20 days ago	Sincerely I not understand about as internally is done timing for emulated cpus and thus being Z80 is as being much "simple" to emulate at point being strange for me only having 5x Z80 being that high slowdown was as an performance regression. I have loaded an high number of games using multiple Z80 and confirm the recent new Z80 core not does slowdown for several games. If an game in source line use "config.set_perfect_quantum(m_maincpu)" and so require high cpu usage that slowdown is really expected. However I say again the Z80 changes not are doing slowdown for several games.
No.22785 JimCarlTay Tester 14 days ago	Consistent 100% game speed on my computer. Unable to reproduce.