PiStorm Chat

General discussions or ideas about hardware.
Badwolf
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Joined: Tue Nov 19, 2019 12:09 pm

Re: PiStorm Chat

Post by Badwolf »

Badwolf wrote: Wed Aug 03, 2022 12:35 pm
alexh wrote: Wed Aug 03, 2022 12:05 pm Perhaps turn off "turbo"?
Can try that as an experiment, but the cycles are quite quantised, so it would need a big change to make any noticiable difference, I suspect.
So running without 'turbo' mode (governor = powersave; frequency = 600MHz), we see data transfer rates of 1.4MB/s (down from 1.8) and a relative RAM measurement in GB6 of 35% (down from 50%).

The fact it's so measurable shows there is a significant Musashi overhead. We may have to go straight to Emu68. :(

BW
DFB1 Open source 50MHz 030 and TT-RAM accelerator for the Falcon
DSTB1 Open source 16Mhz 68k and AltRAM accelerator for the ST
Smalliermouse ST-optimised USB mouse adapter based on SmallyMouse2
FrontBench The Frontier: Elite 2 intro as a benchmark
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alexh
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Location: Oxfordshire

Re: PiStorm Chat

Post by alexh »

Principal ASIC Engineer - SystemVerilog, VHDL
Thalion Webshrine - http://thalion.atari.org
STfm,STe,MegaSTe,Falcon060
A500+,A600,A4000/060,CD32,CDTV
Badwolf
Posts: 1316
Joined: Tue Nov 19, 2019 12:09 pm

Re: PiStorm Chat

Post by Badwolf »

alexh wrote: Thu Aug 04, 2022 12:03 am
I've never even *seen* a Pi4 :P

I think I'll try to shake out as many issues as I can from this and take a peek at the Emu68 stuff.

Another suggestion has been to not wait for confirmation of writes completing, but that would make a mess of the barely-working bus errors again!

Perhaps shortening the write cycle would help, mind.

BW
DFB1 Open source 50MHz 030 and TT-RAM accelerator for the Falcon
DSTB1 Open source 16Mhz 68k and AltRAM accelerator for the ST
Smalliermouse ST-optimised USB mouse adapter based on SmallyMouse2
FrontBench The Frontier: Elite 2 intro as a benchmark
Badwolf
Posts: 1316
Joined: Tue Nov 19, 2019 12:09 pm

Re: PiStorm Chat

Post by Badwolf »

By ignoring bus errors on writes (bad thing) and just handing it off to the hardware and continuing to process the emulated CPU, I've been able to get writes up to 100%.

There's a fair way to go on reads, though. Average throughput on gembench is up to 68% and, if cheating by switching to 020 emulation that can be snuck up to 75%, but still not good enough.

Interrupts are likely to still be a problem -- not responding quickly enough, I suspect (Frontier looks like its' running under a strobe as the palette changes at the wrong time), but one that can be put off safely for now.

</update>

BW
DFB1 Open source 50MHz 030 and TT-RAM accelerator for the Falcon
DSTB1 Open source 16Mhz 68k and AltRAM accelerator for the ST
Smalliermouse ST-optimised USB mouse adapter based on SmallyMouse2
FrontBench The Frontier: Elite 2 intro as a benchmark
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alexh
Posts: 242
Joined: Tue Oct 17, 2017 4:51 pm
Location: Oxfordshire

Re: PiStorm Chat

Post by alexh »

Looks like you're making good progress. Thanks for all your time. We the community salute you.
Principal ASIC Engineer - SystemVerilog, VHDL
Thalion Webshrine - http://thalion.atari.org
STfm,STe,MegaSTe,Falcon060
A500+,A600,A4000/060,CD32,CDTV
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