Just wondering what the impact of the Spectre vulnerability will be on Julia. It looks like LLVM will introduce a mitigation that basically disables the use of indirect jump instructions, which has the potential to negate most peformance benefit of branch prediction. More qualified analysis can be found in this HackerNews comment thread.
What I’m curious about:
- Do Julia devs think that such a change should be incorporated into Julia? Or could any security impact on Julia code be ruled out?
- If such a change is necessary, it’s probably too late for Julia 1.0. Could it be done in a non-breaking way during the 1.x development line?
- If I understand correctly, the performance hit could be rather big for code that is heavy on virtual function calls. But “good” Julia code should then not be affected so much, right? Considering that having more information avalailble at compile time and aggressive inlining should reduce the need for virtual function calls.
Thanks for your insights!