3 ms·

Great post! Percentage-wise, how many hot call points have moved to static call sites versus remain based on retpoline? Are there any in-vivo performance measu

• woodruffw 6y ago
  Thank you! Unfortunately, I don't have numbers for this. The patchset itself contains some changes to `perf_events`, as well as a few other subsystems. I also saw some summaries documenting performance improvements in the mid-single-digit range (3-5%), but I'm not aware of anything in-vivo. The kernel mailing list for this patch range[1] might be a good reference. [1]: https://lore.kernel.org/lkml/cover.1547073843.git.jpoimboe@redhat.com/T/ https://lore.kernel.org/lkml/cover.1547073843.git.jpoimboe@r...
• bonzini 6y ago
  There aren't many static calls yet, but for example I am planning to use them for KVM (which has lots of indirect calls in order to support both Intel and AMD virtualization extensions). Besides some improvements in sheer cycle count, it would also allow some code cleanups, removing code that has to be duplicated to avoid sticking a retpoline in the middle of a hot path.