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

On Tue, 5 Sep 2017, Randy Dunlap wrote:

On 09/05/17 15:53, Andrew Morton wrote:

quoted

On Tue, 5 Sep 2017 22:05:00 +0300 Alexey Dobriyan [off-list ref] wrote:

quoted

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