[Arm-netbook] about Risc-V and Power,

Lauri Kasanen cand at gmx.com
Thu Jan 2 08:03:51 GMT 2020

On Wed, 1 Jan 2020 20:59:47 -0500
zap <zapper at disroot.org> wrote:

> Isn't Risc-V supposedly  supposed to be more secure and isn't open power
> based on the old risc? I am just wondering, if the level of evils risc-v
> has done, justifies abandoning usage of it when you could just as easily
> do some risc-v processors with or without their help

The ISA has nothing to do with security. All the meltdown/spectre stuff
is implementation, hence why AMD is unaffected by much of it.

> and moreover,
> power, doesn't it require an immense, even crazy amount of watts?
> I guess my point is, they use more battery power than intel even. And
> intel is bad enough.

The old Mac laptops basically tried to use a desktop cpu on mobile,
kinda what Intel P4 did. It's about design choices, not the
instructions. There are a number of lower-wattage Power cpus; using
that does not mean the chip will burn lots.

The POWER9 chips IBM offers, 90W for 4-core, 160W for 8-core and 190W
for more, they are server chips. Compare to Epycs and Xeons, not to
mobile 15W ones. The older Power core in the Wii U uses around 20W. All
about choices.

> Okay, well you did say openpower, what is that?

IBM released the ISA under open terms, and started the OpenPower
foundation to govern it.

> Oh really? That's odd... hmm... so you have to abandon risc-v you are
> saying? Pity that's your only option. I wonder if I should tell others
> about this.

Just making sure it's clear, the ISA choice is about licensing and
extensibility. Risc-v, mips, power are about equal in other ways; in
some ways, power and mips are better, like existing compiler support.
IOW dropping risc-v is not a loss in ways most users would care about.

- Lauri

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