Re: [PATCH 1/2] pidmap(2)

From: Thomas Gleixner
Date: Wed Sep 06 2017 - 04:30:15 EST


On Tue, 5 Sep 2017, Randy Dunlap wrote:
> On 09/05/17 15:53, Andrew Morton wrote:
> > On Tue, 5 Sep 2017 22:05:00 +0300 Alexey Dobriyan <adobriyan@xxxxxxxxx> wrote:
> >
> >> Implement system call for bulk retrieveing of pids in binary form.
> >>
> >> Using /proc is slower than necessary: 3 syscalls + another 3 for each thread +
> >> converting with atoi().
> >>
> >> /proc may be not mounted especially in containers. Natural extension of
> >> hidepid=2 efforts is to not mount /proc at all.
> >>
> >> It could be used by programs like ps, top or CRIU. Speed increase will
> >> become more drastic once combined with bulk retrieval of process statistics.
> >
> > The patches are performance optimizations, but their changelogs contain
> > no performance measurements!
> >
> > Demonstration of some compelling real-world performance benefits would
> > help things along a lot.
> >
>
> also, I expect that the tiny kernel people will want kconfig options for
> these syscalls.

And of course that stuff wants the corresponding man pages written up.

Thanks,

tglx