Comment by brucehoult | Hacker News Reader

Comment by brucehoult | Hacker News Reader

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> Avoid. That particular platform is really incredibly slow, Cortex-A5x level.

If you avoid it then you won't be using RISC-V at all, right now.

Along with the JH7110, it is the fastest RISC-V CPU you can buy off the shelf today. That will probably change late in this year, but for now you can't do significantly better.

Overall the two (and the SG2042, same cores as the TH1520 but 64 of them, plus L3 cache) are very similar in speed. The C910 can be 30% to 50% faster on some microbenchmarks. The JH7110 is usually about 10% faster on system level real world tasks e.g. building software. Not enough to notice unless you sit both side by side.

> And with RVV 0.7.1 instead of 1.0 too

Which matters much less than it used to, as gcc 14 can compile C code with RVV intrinsics to either.

Just today I took someone's RVV 1.0 test code, which they'd only been able to run on simulators, and compiled it and ran it on my TH1520 LicheePi 4A, with only Makefile changes (`-march=rv64gc_xtheadvector` instead of `-march=rv64gcv`).

https://www.reddit.com/r/RISCV/comments/1b57gib/comment/kt4t...

> If you avoid it then you won't be using RISC-V at all, right now.

I'm sorry this just isn't true. The K230 has RVV 1.0 hardware and has been available for 5 months.

> Which matters much less than it used to, as gcc 14 can compile C code with RVV intrinsics to either.

This is still a huge problem for fragmentation. Multimedia libraries in FFmpeg and VideoLAN use hand written assembly and only support standards compliant RVV 1.0.

There is no reason to ever produce a binary for RVV 0.7.1, it will simply fail if run on standards compliant hardware.

Fully agreed.

> The JH7110 is usually about 10% faster on system level real world tasks e.g. building software.

Pretty sure the U74 CPU from the JH7110 is way worse than the C910 from the TH1520 on pretty much all aspects. So my guess is that your metric is mostly explained by the fact that the JH7110 has a PCIe bus which allows plugging in an SSD rather than an eMMC or SD Card. But such SSD also has a cost. I think this gives some perspectives.

It's not a "metric" it's real-world use. Whatever the causes, the CPU core is not the only component in an overall system.

I use both of these boards every day. Constantly, as it's my work.

Building my RVV 0.7.1 gcc 9.2 snapshot takes 111 min on the U74 VisionFive 2, 122 minutes on the C910 LicheePi 4A.

Running DotNET "LINQ" test suite takes 4m30s on VisionFive 2, 5m30s on LicheePi 4A.

Doing `emacs --eval '(kill-emacs)' hello.c` takes 0.72s on VisionFive 2, 0.75s on LicheePi 4A. Close, but the C910 does not win.

Yes, the C910 significantly beats the U74 on every micro-benchmark. Dhrystone, coremark, my "primes" test https://hoult.org/primes.txt, memcpy...

https://hoult.org/TH1520_memcpy.txt

https://hoult.org/JH7110_memcpy.txt

It doesn't translate to the real world, at least in the TH1520 SoC, on the LicheePi 4A sbc.

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