RetroArch 1.7.2 - better latency than original hardware through new runahead method

[Retro-Nerd]

Interesting. Probably very CPU intensive to remove the lag in games like Super Mario World. We'll see how good it works when RetroArch 1.7.2 is released.

https://www.libretro.com/index.php/r...nahead-method/

discussion:

https://forums.libretro.com/t/input-...rnal-lag/15075

[solidcore]

It's interesting, some games would benefit from this a lot, like snes super mario as the news release suggests.

Personally you won't catch me running retroarch, I wish them luck, I hope it's a per game configuration - per core seem's a little messy to me.

[Retro-Nerd]

Sure, per game setting is possible. That's why i like RetroArch. Together with Launchbox it's great. Even on Windows PCs. A lot of standalone emuators are outdated, when it comes to video/audio output.

[Retro-Nerd]

How to check the amount of lag frames a game has

RetroArch has the ability to pause a core and advance it frame by frame. Perform the following steps to determine the amount of lag frames of a game:

• Pause emulation (press ‘p’ button on keyboard).
• Press and hold the jump button on the controller.
• Advance emulation frame by frame (press ‘k’ button on keyboard) until the character jumps.

The number of k presses before you get a reaction should be the number of lag frames you can safely remove with run ahead.

Amazing. This works just great with the new Runahead latency reduction. The original ingame lag is just gone in tested games like Super Mario World (2fps), Aladdin Mega Drive (1fps) or Jackie Chan PC-Engine (1fps).

https://www.libretro.com/index.php/r...-7-2-released/

[Amiga1992]

Wow Wii version supports it and I didn't know!
I have to try but I feel it'll just ram the CPU too much.

[lordofchaos]

Wow indeed, this is great news! Been holding off until this was implemented, Donkey Kong Country here I come.

[Leandro Jardim]

Originally Posted by lordofchaos

Wow indeed, this is great news! Been holding off until this was implemented, Donkey Kong Country here I come.

I agree, but will RetroArch implement also some day the same Lagless VSync that WinUAE uses? Or maybe that and this new feature discussed here are different things?

[Retro-Nerd]

These are indeed different things. Toni removed the lag caused through the PC software (which also improves the lag of the used monitors).

This technique here removes the programmed lag you'll find in the games itself. We'll see if RetroArch combines it later with the lagless Vsync. But it's already pretty good with Freesync hardware and the "Hard GPU Sync" setting.

[Amiga1992]

This poses the question though: wouldn't bettering the control lag of the original machine definitely be a form of cheating?

[Retro-Nerd]

Nah! Why? Do you think the difficulty was programmed with the controls lag in mind? I don't think so.

[Leandro Jardim]

Originally Posted by Retro-Nerd

These are indeed different things. Toni removed the lag caused through the PC software (which also improves the lag of the used monitors).

This technique here removes the programmed lag you'll find in the games itself. We'll see if RetroArch combines it later with the lagless Vsync. But it's already pretty good with Freesync hardware and the "Hard GPU Sync" setting.

So this explains everything. Thank you Retro-Nerd.

[Amiga1992]

Originally Posted by Retro-Nerd

Nah! Why? Do you think the difficulty was programmed with the controls lag in mind? I don't think so.

Enhancing your response time seems like cheating to me. At the very least it changes the way you play the game for sure.

Keep in mind speed runners and score setters usually lay games very tightly in sync with the game's timing and any change in the control lag will affect gameplay for better or worse.

If you played Super MArio Bros for 20 years with a 2 frame lag, suddenly having no frame lag will set your playing off. People get used to things like lag and act accordingly pre-empting actions.

[Retro-Nerd]

Maybe, but i don't care about speed-runs. And at the moment it only compensates the normal lag caused due to the emulators/monitors/input devices.

[Amiga1992]

YEah I didn't mean you (or I) cared specifically, I just wondered, because this is a new technique, if it would end up within the cheating realm. Just curiosity.

[Anubis]

Video by ETA Prime

[ Show youtube player ]

[Valken]

Very cool and hope to see more progress for other emulators as well...

OT - but is there something like RA but with a more windows friendly GUI like WinUAE, BluMSX or SpecEMU , while still supporting multi emulators? I hate the RA GUI on PC. It is perfect for arcade /console type cabinets though.

[Retro-Nerd]

RA starts changing. With v1.7.3 it has a desktop GUI. For now only scanning and starting games stuff, playlists etc. The painfully config options will probably change too at some point.

https://www.libretro.com/index.php/r...-7-3-released/

Well, for using game lists and databases in a desktop GUI: Launchbox is fine. For the deskop style game lists you need a registered version though.

[Anubis]

I got forever update license for Launchbox that I purchased few thanksgiving back on black Friday sale for 20 bucks.

It works really great with many emulators, including RA.

[Valken]

OT - I'm looking at it now and its not user friendly to setup. Tried the Hatari core and could not find the bios.

Updating is fantastic though... it just blindly eats up all of my bandwidth that I cannot stream, d/l or do anything else other than type text on forums!

Really needs a bandwidth limiter button so we can turn it on and off. Also dumb as a brick as I can click it to re/dl the same updates over and over and it does it without keeping a queue list in check...

[Anubis]

Updating - as core or db updater or any other updater??

Biggest issue for RA is that it does not have simple 'update me or update all' button.