From: Randy Dunlap <rdunlap-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
To: Andrew Morton
<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
Alexey Dobriyan
<adobriyan-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Tatsiana Brouka <Tatsiana_Brouka-uRwfk40T5oI@public.gmane.org>,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Aliaksandr Patseyenak
<Aliaksandr_Patseyenak1-uRwfk40T5oI@public.gmane.org>
Subject: Re: [PATCH 1/2] pidmap(2)
Date: Tue, 5 Sep 2017 16:02:37 -0700 [thread overview]
Message-ID: <d538b917-3e3e-827c-7ca0-5493961cf6f1@infradead.org> (raw)
In-Reply-To: <20170905155320.a683a4853b21a3be32d8b529-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
On 09/05/17 15:53, Andrew Morton wrote:
> On Tue, 5 Sep 2017 22:05:00 +0300 Alexey Dobriyan <adobriyan-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> 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.
--
~Randy
next prev parent reply other threads:[~2017-09-05 23:02 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-05 19:05 [PATCH 1/2] pidmap(2) Alexey Dobriyan
2017-09-05 19:06 ` [PATCH 2/2] fdmap(2) Alexey Dobriyan
2017-09-05 22:53 ` [PATCH 1/2] pidmap(2) Andrew Morton
[not found] ` <20170905155320.a683a4853b21a3be32d8b529-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
2017-09-05 23:02 ` Randy Dunlap [this message]
[not found] ` <d538b917-3e3e-827c-7ca0-5493961cf6f1-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
2017-09-06 8:30 ` Thomas Gleixner
2017-09-06 9:04 ` Alexey Dobriyan
[not found] ` <CACVxJT_vg7DnxSGmMtRT5aLCL=jutD94-yXaNOBwrJc-G+g_1w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-09-07 2:04 ` Andy Lutomirski
[not found] ` <CALCETrUFnfncs9QdZ4LTeFemVTCx-27bu88M=3U=RKBT8Oykwg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-09-07 5:06 ` Djalal Harouni
2017-09-07 9:47 ` Alexey Dobriyan
2017-09-07 9:43 ` Alexey Dobriyan
2017-09-06 8:55 ` Alexey Dobriyan
2017-09-07 10:08 ` Dmitry V. Levin
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