Auto Frame-skip selector

Willysonicteam · 04-12-2009, 01:43 AM #1

Hi.
Is possible integrated this option in the next version this emulator?
this is other emulator,only is a little example.
this option decreased the fps,and stabilize the speed of game.
Thanks.

04-12-2009, 02:05 AM #2

They might add this eventually but as of now it's not a priority.

~~etking~~ · 03-23-2012, 06:29 AM #3

An automatic frame skipping function is really missing where frame skipping is only applied when needed to maintain 100% game speed. Maybe this could help fixing HLE audio slowdowns (maybe I'm wrong).

**Anti-Ultimate** · 03-23-2012, 07:23 AM #4

Holy mother of old thread, wtf did you bump this?

***Shonumi*** · (This post was last modified: 03-23-2012, 08:19 AM by Shonumi.)

etking Wrote:An automatic frame skipping function is really missing where frame skipping is only applied when needed to maintain 100% game speed. Maybe this could help fixing HLE audio slowdowns (maybe I'm wrong).

At any rate, frame skipping shouldn't help you all that much with actual game speed.

(02-03-2012, 05:47 AM)HawaiianPunch Wrote: Nooooo! Frame skipping does render the frame, it just doesn't display it. That why it really gives almost no performance increase.

~~etking~~ · (This post was last modified: 03-23-2012, 09:13 AM by etking.)

(03-23-2012, 07:23 AM)Anti-Ultimate Wrote: Holy mother of old thread, wtf did you bump this?

I wanted to open a new thread as this one was suggested.
Frame skipping in Dolphin really is useless the current way and should be replaced by a real automatic frame skipping like found in almost all emulators since NES emulation days in case that was possible. Skipped frames should not be calculated and game speed should always be at 100%. The Emulator should decide how many frames to skip and adjust this value dynamically based on audio speed for example.

Since this is a very basic and must-have function for any emulator, I really wonder why it is not implemented in dolphin. Even users with a fast system could benefit since short and small frame drops would have no impact on game speed at all.

scummos · 03-23-2012, 09:29 AM #7

(03-23-2012, 08:16 AM)Shonumi Wrote:
(02-03-2012, 05:47 AM)HawaiianPunch Wrote: Nooooo! Frame skipping does render the frame, it just doesn't display it. That why it really gives almost no performance increase.

While we're at that, why is that? I didn't yet understand the reason for this.

***Shonumi*** · (This post was last modified: 03-23-2012, 11:30 AM by Shonumi.)

(03-23-2012, 09:08 AM)etking Wrote: I wanted to open a new thread as this one was suggested.
Frame skipping in Dolphin really is useless the current way and should be replaced by a real automatic frame skipping like found in almost all emulators since NES emulation days in case that was possible. Skipped frames should not be calculated and game speed should always be at 100%. The Emulator should decide how many frames to skip and adjust this value dynamically based on audio speed for example.

Since this is a very basic and must-have function for any emulator, I really wonder why it is not implemented in dolphin. Even users with a fast system could benefit since short and small frame drops would have no impact on game speed at all.

Thing is, every emulator is different and performs its tasks differently, especially when it comes to different systems. Simply because other emulators do it doesn't mean it's trivial for another to accomplish it. For example, Desmume doesn't scale the native DS resolution like Dolphin, PCSX2, JPCSP, and etc can for their emulated systems. It's possible, but the way the emulator's set up, it's hard to accomplish. Don't assume that one thing can be applied easily in one program to others, even if the programs share the same general function.

(03-23-2012, 09:29 AM)scummos Wrote: While we're at that, why is that? I didn't yet understand the reason for this.

dannzen Wrote:frame skip doenst improve your performance...
you cant skip a calcuation
and knowing the result after it...
(dolphin is cpu heavy not gpu heavy...)
a gpu frame could be skipped...
but not a cpu step

Dimitri Wrote:Frame-skipping usually *won't* give you any noticeable performance improvement, especially if the emulation is bottlenecked by your CPU (which I'm quite confident about, especially given how weak your CPU/APU is for modern emulation).
Even if you tell Dolphin to use frame-skipping, the CPU thread STILL has to emulate the same game code, and STILL will be the bottleneck in your situation (you're lowering the graphics throughput without reducing the cost of emulation).

I think it boils down to the fact that the calculation has to happen, i.e. you can't skip the code that's calculated for the emulated CPU. I imagine, to keep the GPU in-sync, you can't just not run the code necessary to emulate the graphics either. You could, however, just not show the frames at all during the rendering, which is how Dolphin does it. I'm not an expert though, so hopefully someone could clear this up.

**skid** · 03-23-2012, 03:20 PM #9

Frame skipping cannot really be done on modern consoles (modern as in any console that uses 3D polygons instead of sprites like the NES, SNES, Megadrive/Genesis). The reason is that the CPU communicates to the GPU using a "ring-buffer". In Dolphin we call that the FIFO. The PCSX2 team also have blogs written up on the ring-buffer used in the PS2.

Unlike old consoles which use an interrupt to signal that a frame is finishing, 3D consoles continuously send a stream of 3D commands to the screen (hence the reason why it's called a ring) with no start or end points.

Without start or end points, Dolphin cannot skip frames because it does not know when the frame starts or ends - quite different from a NES emulator.

Willysonicteam · 04-25-2012, 10:28 PM **#10**

(03-23-2012, 03:20 PM)skid Wrote: Frame skipping cannot really be done on modern consoles (modern as in any console that uses 3D polygons instead of sprites like the NES, SNES, Megadrive/Genesis). The reason is that the CPU communicates to the GPU using a "ring-buffer". In Dolphin we call that the FIFO. The PCSX2 team also have blogs written up on the ring-buffer used in the PS2.

Unlike old consoles which use an interrupt to signal that a frame is finishing, 3D consoles continuously send a stream of 3D commands to the screen (hence the reason why it's called a ring) with no start or end points.

Without start or end points, Dolphin cannot skip frames because it does not know when the frame starts or ends - quite different from a NES emulator.

thanks for answer!,is a worthwhile.