Re: [PATCH v4 0/5] getcpu_cache system call for 4.6

From: H. Peter Anvin
Date: Tue Feb 23 2016 - 20:37:58 EST


On 02/23/2016 03:28 PM, Mathieu Desnoyers wrote:
> Hi,
>
> Here is a patchset implementing a cache for the CPU number of the
> currently running thread in user-space.
>
> Benchmarks comparing this approach to a getcpu based on system call on
> ARM show a 44x speedup. They show a 14x speedup on x86-64 compared to
> executing lsl from a vDSO through glibc.
>
> I'm added a man page in the changelog of patch 1/3, which shows an
> example usage of this new system call.
>
> This series is based on v4.5-rc5, submitted for Linux 4.6.
>
> Feedback is welcome,
>

What is the resulting context switch overhead?

-hpa