On Tue, Sep 26, 2017 at 03:34:36PM +1000, Michael Ellerman wrote: > Cyril Bur <cyril...@gmail.com> writes: > > This was written for userspace which doesn't have to explicitly enable > > VMX in order to use it - we need to be smarter in the kernel. > > Well the kernel has to do it for them after a trap, which is actually > even more expensive, so arguably the glibc code should be smarter too > and the threshold before using VMX should probably be higher than in the > kernel (to cover the cost of the trap).
A lot of userspace code uses V*X, more and more with newer CPUs and newer compiler versions. If you already paid the price for using vector registers you do not need to again :-) > But I digress :) Yeah sorry :-) Segher
