On Thu, 2016-15-09 at 09:04:46 UTC, Nicholas Piggin wrote: > mtmsrd with L=1 only affects MSR_EE and MSR_RI bits, and we always > know what state those bits are, so the kernel MSR does not need to be > loaded when modifying them. > > mtmsrd is often in the critical execution path, so avoiding dependency > on even L1 load is noticable. On a POWER8 this saves about 3 cycles > from the syscall path, and possibly a few from other exception returns > (not measured). > > Signed-off-by: Nicholas Piggin <npig...@gmail.com>
Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/49d09bf2a66f4b5a6eabefb0d4 cheers