On Wed, Sep 6, 2017 at 3:16 PM, Andi Kleen <a...@firstfloor.org> wrote: > Andy Lutomirski <l...@kernel.org> writes: >> >> - Lots of people (Linus included) have asked to convert the entry >> code to pop registers on exit instead of movqing them off the >> stack. This makes a bunch of progress in that direction. > > You should benchmark it on Atoms. Likely it's a regression there > because they don't have the special PUSH/POP acceleration.
I'm not entirely sure this is a worthwhile reason. Atom will lose a few cycles due to POP throughput, but there's a lot less decode bandwidth needed and we save a cache line or two. --Andy
