Author Topic: The CPU underclocking is a great addition!  (Read 193 times)

Offline el_rika

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The CPU underclocking is a great addition!
« on: November 05, 2019, 04:24:59 AM »
I just tried Progear with CPU set to 90% and it is very very close to real PCB in terms of overall speed and especially slowdown in specific moments. Previously, the in and outs of turning the bullets in diamonds was a bit too fast and jumpy, but now it's slower and much closer to how PCB handles the transitions.

More testing is required, but amazing job guys!!


[played in Retroarch 64 mobile]

Offline barbudreadmon

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Re: The CPU underclocking is a great addition!
« Reply #1 on: November 05, 2019, 06:14:41 AM »
Actually it was always there in the codebase, but the core option in the libretro port wasn't in sync with the standalone setting, it was a residue of the old fbalpha port (now called fbalpha2012) and i never bothered looking into it until a few months ago.

Offline dink

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Re: The CPU underclocking is a great addition!
« Reply #2 on: November 05, 2019, 09:22:15 AM »
So you mean all those times I did a Progear 2-all @ 100% cpu with tons of crystal avalanches in fb it was actually harder than the pcb due to lack of proper slowdown?  :p

Offline el_rika

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Re: The CPU underclocking is a great addition!
« Reply #3 on: November 06, 2019, 04:52:35 PM »
So you mean all those times I did a Progear 2-all @ 100% cpu with tons of crystal avalanches in fb it was actually harder than the pcb due to lack of proper slowdown?  :p

You sir are a master!    :p

My best is No miss No Bomb up to Level 3 boss. It all goes downhill from there, and quite fast   :redface:

Offline el_rika

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Re: The CPU underclocking is a great addition!
« Reply #4 on: November 07, 2019, 01:58:09 PM »
Update: Ketsui and Daioujou (both using the same driver) are not working with the CPU underclock option. Underclocking the CPU does nothing for these games.  Espgaluda is the same driver and most likely will be similar.

Esprade (and most likely all games with that driver) is working and, as with Progear, a CPU @ 90 - 95%  makes the busy scenes a bit slower and closer to PCB.
« Last Edit: November 07, 2019, 03:01:56 PM by el_rika »

Offline dink

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Re: The CPU underclocking is a great addition!
« Reply #5 on: November 07, 2019, 07:09:01 PM »
Only a few drivers support this.  I try to add this sometime for those games when not so busy. (or you could - fb is open source).

best regards,
- dink

Offline barbudreadmon

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Re: The CPU underclocking is a great addition!
« Reply #6 on: November 09, 2019, 03:03:05 AM »
el_rika, i backported this feature from jan_klaassen's special version (https://neo-source.com/index.php?topic=3162.0), however :
- it breaks older pgm savestates
- it only works with the pgm games not using the additional arm7 cpu (ddp3 & ket don't use it)
- it lacks proper testing, so please be vigilant about potential glitches and report them

Offline el_rika

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Re: The CPU underclocking is a great addition!
« Reply #7 on: November 09, 2019, 05:36:20 AM »
So Ketsui should work then? It definitely doesn't. There's clear added slowdown in mame with CPU barely underclocked, while there's no change in FBN at 50% cpu.

Where it works though, it's really great. Esprade and Progear really work well, no glitches. Gonna test Garregga next.

@dink, my programming skills start and end with the classic "LOAD"   :smilie:  so i'm really grateful for all the work you put into this emulator!
« Last Edit: November 09, 2019, 05:41:18 AM by el_rika »

Offline barbudreadmon

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Re: The CPU underclocking is a great addition!
« Reply #8 on: November 09, 2019, 07:01:06 AM »
So Ketsui should work then? It definitely doesn't.
I think it does for me (game becomes sluggish when i set clock to low values), maybe make sure you aren't using ketbl (this one uses the arm7 cpu) and you are using latest fbneo core (maybe the libretro buildbot didn't finish the rebuilding when you updated your core)
« Last Edit: November 09, 2019, 07:02:49 AM by barbudreadmon »

Offline dink

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Re: The CPU underclocking is a great addition!
« Reply #9 on: November 09, 2019, 08:16:59 AM »
If that feature doesn't help (from jan's core), please revert it.  I really don't feel good about those changes for some reason :(