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It's not a dumb name change, targeting skylale could generate illegal instructions on modern AMD cpus e.g they lacking TSX or SGX. This is about defining the co
by The_rationalist 6y ago
It's not a dumb name change, targeting skylale could generate illegal instructions on modern AMD cpus e.g they lacking TSX or SGX.
This is about defining the common intersection of both vendors by generation
- my123 6y agoAnd assuming those are present for a given gen is even dumber sadly. There are Comet Lake CPUs with no AVX at all: all Pentiums/Celerons. Every 10th generation Intel CPU onwards, at least on the client side, doesn't support TSX.
- jcranmer 6y ago> they lacking TSX or SGX. Note that the SGX instructions are system only, so the compiler isn't generating them usually. The hardware lock elision instructions in TSX are specifically chosen so that they act as NOPs on processors that don't support TSX.
- my123 6y agoHardware lock elision was disabled via a microcode update. (see https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c2955f270a84762343000f103e0640d29c7a96f3 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/lin...)
- throwaway2048 6y agoNot to mention TSX instructions have been broken in one way or another since their introduction, and now have been removed entirely in new intel silicon.