On March 9, 2017 9:42:57 PM EST, Andy Lutomirski <l...@amacapital.net> wrote: >On Thu, Mar 9, 2017 at 2:42 PM, Steven Rostedt <rost...@goodmis.org> >wrote: >> From: "Steven Rostedt (Red Hat)" <rost...@goodmis.org> >> >> Linus mentioned that doing two compares can be replaced by a single >> compare. That is, instead of: >> >> movq $repeat_nmi, %rdx >> cmpq 8(%rsp), %rdx >> ja not_in_region >> movq $end_repeat_nmi, %rdx >> cmpq 8(%rsp), %rdx >> ja in_region >> >> we can replace that with: >> >> movq 8(%rsp), %rdx >> subq $repeat_nmi, %rdx >> cmpq $end_repeat_nmi-repeat_nmi, %rdx >> jb in_region > >Seems reasonable to me. Good luck ever noticing the speedup :) >
It had nothing to do with speedup. Linus said that the current code makes the assembly programmer in him die a little. I want to cure that. -- Steve >--Andy -- Sent from my Android device with K-9 Mail. Please excuse my brevity.
