Messages in this thread | | | Date | Wed, 12 Sep 2018 16:17:26 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [PATCH v3] x86/vdso: Handle clock_gettime(CLOCK_TAI) in vDSO |
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On Wed, 12 Sep 2018, Florian Weimer wrote: > 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?
We have no intention to change that.
But we surely could provide separate entry points as an extra to avoid a bunch of conditionals.
Thanks,
tglx
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