Author Topic: Milk-V, pin-to-pin compatible RPI-CM4, but RISC-V!  (Read 664 times)

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Offline DiTBhoTopic starter

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Milk-V, pin-to-pin compatible RPI-CM4, but RISC-V!
« on: November 03, 2023, 10:49:01 am »


  • it can't compete in terms of performance (5-6 times slower than a RPI-v4)
  • it's pretty decent in terms of energy efficiency
  • what makes it interesting for me is the ePCI lane and the compatibility with CM4 mobos
See here  :D
The opposite of courage is not cowardice, it is conformity. Even a dead fish can go with the flow
 

Offline brucehoult

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Re: Milk-V, pin-to-pin compatible RPI-CM4, but RISC-V!
« Reply #1 on: November 03, 2023, 12:15:39 pm »
Re performance, even Yearling's wildly inappropriate use of GeekBench 6 to benchmark it shows that when running generic C code it is close to a Pi 4.

For example on the Clang test the Pi CM4 does 358 single core, 788 multi core, while the Mars CM does 248 single core, 839 multi core.

So the Mars CM is actually faster with both using all four cores.

The big performance difference in favour of the Pi is on the benchmarks (most of GeekBench) that use NEON or crypto. The U74 cores in the Mars CM don't have any SIMD or vector facility. RISC-V's Vector ISA was not published until November 2021, while the U74 core is from October 2018.

If you want to compile and run portable C code then it's fine.
 
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Online woofy

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Re: Milk-V, pin-to-pin compatible RPI-CM4, but RISC-V!
« Reply #2 on: November 03, 2023, 01:00:51 pm »
Jeff Geerling recently did a review of this module:
https://youtu.be/RhPKZ5JpbHw?si=oZK31nMw8o1EgrPC

Offline DiTBhoTopic starter

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Re: Milk-V, pin-to-pin compatible RPI-CM4, but RISC-V!
« Reply #3 on: November 03, 2023, 06:32:48 pm »
Re performance

I pre-ordered (purchased?) two modules but have not yet received them, I "trusted" some reviews about the performance. There are people who say it performs badly.

I just noticed though that the Debian they used has some problems.
(they say, don't  update the system, LOL)

I remember some time ago having created a particularly unfortunate Gentoo/MIPS stage3, which, due to an error in the profile (MIPS4 is experimental, especially for R12K), had been compiled so badly that everything was 5 times slower.

Fixed the problem, recompiled everything, it splintered like a rocket!

-

Thanks for your feedback!

At the moment, I'm more interested in being able to exploit the PCIe lane, excellent for adding peripherals to Haiku/RISC-V  :D :D :D
« Last Edit: November 03, 2023, 09:46:09 pm by DiTBho »
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Offline SiliconWizard

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Re: Milk-V, pin-to-pin compatible RPI-CM4, but RISC-V!
« Reply #4 on: November 03, 2023, 08:34:55 pm »
Yes, the main performance difference will be seen if you use vector FP instructions. Then the difference is quite big. If you don't even use FP, or only lightly (nothing computationally intensive), then this RISC-V CPU is probably a pretty adequate replacement.
 


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