Re: [RFC PATCH for 4.16 02/21] rseq: Introduce restartable sequences system call (v12)

From: Christopher Lameter
Date: Fri Dec 15 2017 - 10:05:22 EST


On Thu, 14 Dec 2017, Peter Zijlstra wrote:

> > But my company has extensive user space code that maintains a lot of
> > counters and does other tricks to get full performance out of the
> > hardware. Such a mechanism would also be good from user space. Why keep
> > the good stuff only inside the kernel?
>
> Mathieu's proposal is for userspace, _only_ userspace.

But what we were talking about are instructions that work effectively in
kernel space whose efficiency restartable sequences could bring to user
space.