Re: [PATCH v3] x86/vdso: Handle clock_gettime(CLOCK_TAI) in vDSO

From: Florian Weimer
Date: Wed Sep 12 2018 - 09:01:48 EST

On 09/09/2018 10:05 PM, Thomas Gleixner wrote:
See the patch below. It's integrating TAI without slowing down everything
and it definitely does not result in indirect calls.

On a HSW it slows down clock_gettime() by ~0.5ns. On a SKL I get a speedup
by ~0.5ns. On a AMD Epyc server it's 1.2ns speedup. So it somehow depends
on the uarch and I also observed compiler version dependend variations.

Does this mean glibc can keep using a single vDSO entrypoint, the one we have today?