06405: Multithreading or Hyper Threading is Missing Command-Line

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
06405	Core	Feature	Always	Oct 11, 2016, 03:52	Oct 11, 2016, 07:14

Tester	Zelda189	View Status	Public	Platform
Assigned To		Resolution	No change required	OS
Status [?]	Closed			Driver
Version	0.172	Fixed in Version		Build
		Fixed in Git Commit		Github Pull Request #

Summary	06405: Multithreading or Hyper Threading is Missing Command-Line
Description	Typing the Command Prompt "mame -mt" and the following the error message: Error: unknown option: -mt
Steps To Reproduce
Additional Information	Multithreading is required to run the faster Games. Some HT CPUs are requred by -MT Switch Sega Lindbergh Ghost Squad Rev A and others.
Github Commit

Flags
Regression Version	0.172
Affected Sets / Systems

Attached Files	Multithreading Removed 0.172.png (601,788 bytes) Oct 11, 2016, 03:52 Uploaded by Zelda189

No.13256 Tafoid Administrator Oct 11, 2016, 05:17 edited on: Oct 11, 2016, 05:22	-mt (-multithreading) is gone from source. It caused numerous graphic issues with many drivers and until a solution that does it correctly is developed, the command will not be returning. Examples: http://mametesters.org/view.php?id=5898 and other bugs linked to that. No amount of trickery will allow any current computer to run any of the games you mentioned such as Naomi/Naomi 2/Atomisware/Lindbergh driver or similar game at any playable speed. You are way overstating this command's abilities. If you value that command, you'll need to stick with an older version of MAME which has it present or upgrade your machine. The best you can shoot for right now is a good i5 or i7 with as high Ghz as possible but then then, again, you'll not be able to play most of those later drivers. Closing with No change Required.
No.13260 B2K24 Senior Tester Oct 11, 2016, 07:14	As stated on the wiki page: Does MAME benefit from SMP (symmetric multiprocessing) / HT (Hyper-Threading) / dual cores? No. Previous versions of MAME included a -mt switch which allowed some tasks to be threaded off for use by SMP or multicore systems. However, as of MAME 0.173 this switch has been removed. The benefits from this -mt switch were relatively small, because accurate emulation such as MAME strives for cannot easily be broken up into parallel subtasks (it would be like trying to have a baby in one month by impregnating nine women). We also found that this particular implementation of the -mt switch created a lot of errors. There were exceptions of course, but MAME will have to support them via some new mechanism in the future since the -mt switch has been removed. http://wiki.mamedev.org/index.php/FAQ:Performance

No.13256

Tafoid

Administrator

Oct 11, 2016, 05:17

edited on: Oct 11, 2016, 05:22

-mt (-multithreading) is gone from source. It caused numerous graphic issues with many drivers and until a solution that does it correctly is developed, the command will not be returning.
Examples: http://mametesters.org/view.php?id=5898 and other bugs linked to that.

No amount of trickery will allow any current computer to run any of the games you mentioned such as Naomi/Naomi 2/Atomisware/Lindbergh driver or similar game at any playable speed. You are way overstating this command's abilities.
If you value that command, you'll need to stick with an older version of MAME which has it present or upgrade your machine. The best you can shoot for right now is a good i5 or i7 with as high Ghz as possible but then then, again, you'll not be able to play most of those later drivers.

Closing with No change Required.

No.13260

B2K24

Senior Tester

Oct 11, 2016, 07:14

As stated on the wiki page:

Does MAME benefit from SMP (symmetric multiprocessing) / HT (Hyper-Threading) / dual cores?
No. Previous versions of MAME included a -mt switch which allowed some tasks to be threaded off for use by SMP or multicore systems. However, as of MAME 0.173 this switch has been removed. The benefits from this -mt switch were relatively small, because accurate emulation such as MAME strives for cannot easily be broken up into parallel subtasks (it would be like trying to have a baby in one month by impregnating nine women). We also found that this particular implementation of the -mt switch created a lot of errors. There were exceptions of course, but MAME will have to support them via some new mechanism in the future since the -mt switch has been removed.

http://wiki.mamedev.org/index.php/FAQ:Performance