Messages in this thread | | | From | Alexey Dobriyan <> | Date | Wed, 6 Sep 2017 12:04:09 +0300 | Subject | Re: [PATCH 1/2] pidmap(2) |
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On 9/6/17, Randy Dunlap <rdunlap@infradead.org> wrote: > On 09/05/17 15:53, Andrew Morton wrote: >> On Tue, 5 Sep 2017 22:05:00 +0300 Alexey Dobriyan <adobriyan@gmail.com> >> 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.
We'll add it but the question if it is a good idea. Ideally these system calls should be mandatory and /proc optional.
$ size kernel/pidmap.o fs/fdmap.o text data bss dec hex filename 560 0 0 560 230 kernel/pidmap.o 617 0 0 617 269 fs/fdmap.o
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