alt Hacker NewsThe average bystander might want to write high-performance code for their risc-v cpu. Then they must know precisely which instructions are available and what the performance implications of using them are. E.g., the difference between a shared and non-shared fp register file is huge.
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For the "average bystander" they're going to buy an OS and compatible hardware, or if they're the average programmer they're going to use a compiler and libraries that solve the problem already for them. Very very few people need to worry about the details.
Do high-performance RISC-V CPUs (that you can actually buy) still exist? SiFive Unleashed was great but IIRC it was a single batch that never returned.
You think the average person writes performance optmized code?
If you are on that level then you know pretty well what you are targeting. And even then in 99% of cases you just look at the top level profile.
If you do performance analysis for some specific embeded project that is not using a standard profile, then its a bit more work, but hardly impossible.
If you want to get the absolute most out of a specific CPU that is in your hands then you of course have to refer to the documentation for that specific CPU.
That process doesn't depend on whether it's an x86 or an Arm or a RISC-V.
That's why x86 people refer to the HUGE document maintained by Agner Fog.
If you want your code to run well on all standards-compliant implementations then you write according to the ISA documentation, in this case RVA23. Or ARMv9-A. Or x86_64 v3.