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Comment by joelthelion | Hacker News Reader

What's the significance of this announcement? What are the likely markets for this chip?

China is going to be key here.

It's not just a normal market - China may see this as essential to its ability to develop its technology. It's Made in Chine 2025 policy.

That's taken on new urgency as the west has started cutting China off from western tech - so it may be normal companies wanting some insurance in case intel / arm cut them off (trade disputes etc) AND the govt itself wanting to product its industrial base from cutoff during trade disputes.

I don't have any special knowledge on this, but from the announcement: According to reports, Black Iron [Xuan Tie] 910 can be used to design and produce high-performance end-to-end 5G chips, artificial intelligence and automatic driving.

So I guess they want to sell it as an alternative to ARM/nVidia/Qualcomm in those roles.

For one, RISC-V is fully open hardware unlike x86, amd64, arm and other architectures. More adoption is always a good thing.

RISC-V is an open ISA, but a particular RISC-V chip is not necessarily open hardware. In fact, most probably aren't.

What i don‘t get is how optimizations should work for Risc-V. For e.g. intel chips you can do optimizations for every generation because some things have been optimized in the architecture so you can do different tricks. But with risc-v only the instruction set is the same and every cpu could implement it differently with different performance characteristics. How should someone optimize for this?

There's two ways: Firstly different chips will have different sets of extensions.

Secondly macro-op fusion - you can optimize particular sequences of instructions in order to try to get certain optimized micro ops, and it's expected in future that different sequences will be needed on different cores. A "wrong" sequence will run slowly but still run.

Of course all of this is a PITA from our (software) point of view.

It's been already happening with ARM. Clang has tune flags for cortex-$generation, thunderx, thunderx2 (vulcan), (not upstream yet) emag…

and regular distributions ship generic just like on amd64 :)

Yeah because ARM sells the complete implementation for the ARM core. But with Risc-V there may be hundreds of different implementations, you can‘t really add optimizations for everyone.

Not everyone buys the implementations, I specifically listed multiple non-Cortex ones. Cavium/Marvell ThunderX, ThunderX2 (Broadcom Vulcan), Qualcomm Centriq (press F for Falkor), Ampere eMAG (Skylark), all current Apple stuff, are all very different custom implementations.

TX2 in particular has a fascinating history: https://en.wikichip.org/wiki/cavium/microarchitectures/vulca...

China's market is enough for it. Also all national security stuff.

I'd assume custom server hardware for ali's cloud services.

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