[Cerowrt-devel] risc-v options?

[Dave Taht]

On Tue, Nov 30, 2021 at 2:52 PM David P. Reed <dpreed at deepplum.com> wrote:
>
> For what?

Because it's shiny. Because I don't care for the owner of softbank and
arm very much. Because at least the core is open source, and I'd
really like to try out some long held ideas about reducing context
switch latency. And there's a couple instructions I'd like to add.

>I have recently gotten a MicroSemi RISC-V SoC board with embedded FPGA (or maybe it is better thought of as an FPGA board with multicore hard logic RISC-V host.) Runs Linux very fast. It's not set up to be a router, though - not unless I populate its PCIe  slot with NICs. Standard Linux drivers for PCIe devices all work quite well, so far.

how fast can it context switch? (irtt bench)

I am impressed that it works with anything on pcie.

I was mostly dismissing risc-v as a toy that could never catch up to
arm 3 years ago, but with the enormous chinese investment in it...

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> These early 64 bit RISC-V implementations are pretty darn good, but unlike Intel's Xeons, they don't yet handle memory channel performance very well.

Intel has always had an advantage in on-chip cache.

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> (The 32-bit RISC-V's are really competing with ARM based microcontrollers for embedded systems. I don't find them interesting, though I have a couple sample boards with 32 bit RISC-V cores).

I don't find 32 bit risc-v interesting. I did fiddle with the 128 bit
risc-v stuff for a while.

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> A random guess on my part: even consumer routers will be moving to 64-bit processor designs in the next couple years.

Many already have.

> That's because the price difference is getting quite small, as a percentage of total product cost, and because it is hard to buy "small memory address space" DIMMs. I could be wrong, but extrapolation from today's trends suggests that is more likely than not.

802.11ax standards require - no joke - a 2MByte buffer per station.

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> On Friday, November 26, 2021 3:02pm, "Dave Taht" <dave.taht at gmail.com> said:
>
> > has anyone tried the latest generations of risc-v?
> >
> > https://linuxgizmos.com/17-sbc-runs-linux-on-allwinner-d1-risc-v-soc/
> >
> > --
> > I tried to build a better future, a few times:
> > https://wayforward.archive.org/?site=https%3A%2F%2Fwww.icei.org
> >
> > Dave Täht CEO, TekLibre, LLC
> > _______________________________________________
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> > Cerowrt-devel at lists.bufferbloat.net
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> >



-- 
I tried to build a better future, a few times:
https://wayforward.archive.org/?site=https%3A%2F%2Fwww.icei.org

Dave Täht CEO, TekLibre, LLC