From: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
To: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Balbir Singh <bsingharora@gmail.com>,
Ingo Molnar <mingo@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] proc/schedstat: Expose /proc/<pid>/schedstat if delay accounting is enabled
Date: Thu, 25 Jun 2015 23:57:07 +0530 [thread overview]
Message-ID: <20150625182707.GA15883@naverao1-tp.in.ibm.com> (raw)
In-Reply-To: <CAM_iQpW8+pHOhdnZS7iwE987Qc1AqX0qCRYPvEZx5Xc8Ep+92w@mail.gmail.com>
On 2015/06/25 11:00AM, Cong Wang wrote:
> On Thu, May 28, 2015 at 2:11 AM, Balbir Singh <bsingharora@gmail.com> wrote:
> > On Mon, May 25, 2015 at 12:42 PM, Naveen N. Rao
> > <naveen.n.rao@linux.vnet.ibm.com> wrote:
> >> /proc/<pid>/schedstat is currently only available if CONFIG_SCHEDSTATS is
> >> enabled. But, all the fields that this exposes are available and valid
> >> if CONFIG_TASK_DELAY_ACCT is enabled as well.
> >>
>
> [...]
>
> > The change looks reasonable, from what I can understand you want these
> > changes so that you can use /proc/<pid>/schedstat instead of the
> > netlink interface when CONFIG_TASK_DELAY_ACCT is enabled.
> >
>
> Why?
>
> If you need the procfs interface, just enable CONFIG_SCHEDSTATS.
> If you need the netlink interface, enable CONFIG_TASK_DELAY_ACCT.
> They are just two different interfaces for getting the same sched
> information, so why make this change?
>
> There must be some reason you don't want to enable
> CONFIG_SCHEDSTATS? If so, please add it in the changelog.
>
> My guess is it depends on DEBUG_KERNEL which is not what you
> want? But I see no reason it should have that dependency, it just
> exposes some stats, looks like can be just removed (and moved out
> of Kconfig,debug of course).
The primary issue with CONFIG_SCHEDSTATS is the (slight) additional
overhead it introduces, per Kconfig. Due to this, it is not enabled by
default by some of the distro kernels.
Regards,
Naveen
next prev parent reply other threads:[~2015-06-25 18:27 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-25 7:12 [PATCH] proc/schedstat: Expose /proc/<pid>/schedstat if delay accounting is enabled Naveen N. Rao
2015-05-28 5:11 ` Naveen N. Rao
2015-05-28 9:11 ` Balbir Singh
2015-05-29 6:16 ` Naveen N. Rao
2015-05-29 8:04 ` Ingo Molnar
2015-05-29 8:55 ` Naveen N. Rao
2015-05-29 9:18 ` Ingo Molnar
2015-05-29 9:45 ` Naveen N. Rao
2015-05-29 9:54 ` Ingo Molnar
2015-05-29 17:06 ` Naveen N. Rao
2015-06-02 7:58 ` Ingo Molnar
2015-06-25 8:39 ` Naveen N. Rao
2015-06-25 12:12 ` Ingo Molnar
2015-06-25 18:00 ` Cong Wang
2015-06-25 18:27 ` Naveen N. Rao [this message]
2015-06-25 18:40 ` Cong Wang
2015-06-26 8:39 ` Naveen N. Rao
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20150625182707.GA15883@naverao1-tp.in.ibm.com \
--to=naveen.n.rao@linux.vnet.ibm.com \
--cc=bsingharora@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=xiyou.wangcong@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).