By: ⚛ (0xe2.0x9a.0x9b.delete@this.gmail.com), May 24, 2022 3:37 pm
Room: Moderated Discussions
Simon Farnsworth (simon.delete@this.farnz.org.uk) on May 24, 2022 2:14 pm wrote:
> (snip)
> Heterogeneous ISA where the E cores don't support deprecated instructions is fine - indeed, it's
> a good transition strategy. Heterogeneous cores where the new shiny that everyone is "supposed"
> to use for peak performance is not supported on the E cores is not; in the real world, even with
> statically linked binaries and an ability to recompile the world to support it, the effect of a
> heterogeneous ISA is that people don't use the bits of the ISA that aren't present on all cores.
Just a note: Supporting hetero-ISA CPUs is independent from (i.e: it doesn't depend on) whether the binary is linked (at a particular level/viewpoint of abstraction) statically or dynamically. An application can (potentially) be migrated between different-ISA cores of the CPU 1000 times in 1 second. If the operating system isn't designed to (potentially, theoretically) handle 1000 such migrations per second then it isn't designed to handle the hetero-ISA case well at all.
-atom
> (snip)
> Heterogeneous ISA where the E cores don't support deprecated instructions is fine - indeed, it's
> a good transition strategy. Heterogeneous cores where the new shiny that everyone is "supposed"
> to use for peak performance is not supported on the E cores is not; in the real world, even with
> statically linked binaries and an ability to recompile the world to support it, the effect of a
> heterogeneous ISA is that people don't use the bits of the ISA that aren't present on all cores.
Just a note: Supporting hetero-ISA CPUs is independent from (i.e: it doesn't depend on) whether the binary is linked (at a particular level/viewpoint of abstraction) statically or dynamically. An application can (potentially) be migrated between different-ISA cores of the CPU 1000 times in 1 second. If the operating system isn't designed to (potentially, theoretically) handle 1000 such migrations per second then it isn't designed to handle the hetero-ISA case well at all.
-atom
