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Hmmm I wonder why they don't support SIMD instructions on 5.x kernels. I couldn't find any information on what might have changed that would cause that to be an
by TrueDuality 7y ago
Hmmm I wonder why they don't support SIMD instructions on 5.x kernels. I couldn't find any information on what might have changed that would cause that to be an issue.
- chungy 7y agoLinux 5.0 changed exports that ZFS needed to be GPL-only: https://marc.info/?l=linux-kernel&m=154714516832389&w=2 https://marc.info/?l=linux-kernel&m=154714516832389&w=2
- protomyth 7y agoHow does the exports work that the ZFS folks cannot compile their code with the SIMD instructions? Is there some docs on how this works?
- caf 7y agoThe x86-64 FPU state is quite large so normally the user task's FPU state is only saved/restored on a task switch. This means that if kernel code wants to use the FPU (which includes the SIMD instructions), it has to explicitly request access and return it when it's done. The functions that do that are the exports being referred to here.
- TrueDuality 7y agoWell that's positively pleasant... I really appreciate the link though. Checksumming happens quite frequently I wonder how much the removal of these instructions will impact the performance...