PiStorm Chat

[Badwolf]

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

[alexh]

[Badwolf]

I've never even *seen* a Pi4

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

[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

[alexh]

Looks like you're making good progress. Thanks for all your time. We the community salute you.