By: Doug S (foo.delete@this.bar.bar), May 22, 2022 8:52 pm
Room: Moderated Discussions
⚛ (0xe2.0x9a.0x9b.delete@this.gmail.com) on May 22, 2022 11:51 am wrote:
> You are overly protective of what the Linux kernel currently is. There is no vision of a future
> of heterogeneous CPUs in your posts .... if heterogeneous desktop/notebook CPUs are inevitable
> then you should have a plan for it or make a plan for it. (An example reason why heterogeneous
> CPUs are inevitable in those markets is that endowing _all_ cores in a future desktop machine
> with the ability to predict 4 branches per cycle would be problematic.)
That already exists, Linux handles stuff like "big cores" that are wider and "small cores" that are narrower just fine, so long as they both execute the same ISA. What Linus doesn't want to see are cores that don't support the same ISA, with certain instructions only present on some cores.
If the hardware people give us that Linux will support it, but that doesn't mean he shouldn't go around telling people why he thinks that would be a bad idea. You can't really "plan" for something like this until it appears and you know what you're working with.
> You are overly protective of what the Linux kernel currently is. There is no vision of a future
> of heterogeneous CPUs in your posts .... if heterogeneous desktop/notebook CPUs are inevitable
> then you should have a plan for it or make a plan for it. (An example reason why heterogeneous
> CPUs are inevitable in those markets is that endowing _all_ cores in a future desktop machine
> with the ability to predict 4 branches per cycle would be problematic.)
That already exists, Linux handles stuff like "big cores" that are wider and "small cores" that are narrower just fine, so long as they both execute the same ISA. What Linus doesn't want to see are cores that don't support the same ISA, with certain instructions only present on some cores.
If the hardware people give us that Linux will support it, but that doesn't mean he shouldn't go around telling people why he thinks that would be a bad idea. You can't really "plan" for something like this until it appears and you know what you're working with.
