[Repost; I forgot to copy linux-kernel earlier. Apologies if you see it twice.]
Skylake moved to 32 Last Branch Records, from previously 16. The current call stack LBR implementation reads all LBRs and also saves/restores them on context switch. This patchkit adds some optimizations to avoid extra costs in most cases from the larger number of LBRs for call-stack, unless a nesting larger than 16 is actually needed. It applies on top of the earlier Skylake code. Some of the optimization will also benefit earlier CPUs, such as Haswell. note: one patch is for perf user space, the rest is kernel. -Andi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
