public inbox for linux-rt-users@vger.kernel.org
 help / color / mirror / Atom feed
From: Thomas Gleixner <tglx@linutronix.de>
To: "Patel, Vedang" <vedang.patel@intel.com>
Cc: "ranshalit@gmail.com" <ranshalit@gmail.com>,
	"julia@ni.com" <julia@ni.com>,
	"linux-rt-users@vger.kernel.org" <linux-rt-users@vger.kernel.org>,
	"bigeasy@linutronix.de" <bigeasy@linutronix.de>,
	"tlsmith3777@gmail.com" <tlsmith3777@gmail.com>,
	"Hart, Darren" <darren.hart@intel.com>
Subject: Re: Regression on rt kernel while using POSIX timers
Date: Tue, 7 Mar 2017 18:03:03 +0100 (CET)	[thread overview]
Message-ID: <alpine.DEB.2.20.1703071800330.3584@nanos> (raw)
In-Reply-To: <1488852108.29259.85.camel@intel.com>

On Tue, 7 Mar 2017, Patel, Vedang wrote:
> On Mon, 2017-03-06 at 12:29 +0100, Thomas Gleixner wrote:
> 
> > This is simple to achieve for timers where the signal is directed to
> > a thread, but it's way more complex for process wide signal delivery.
> > 
> So, does this mean that we should be asking people not to use POSIX
> timers until this is corrected?

Well, we always recommended clock_nanosleep() to be used and to avoid
signal based timers when ever possible.

> Also, Is there a way to specify which ktimersoftd thread (essentially
> selecting a particular CPU)to use while creating a timer? Currently,
> the ktimersoftd thread corresponding to the thread on which the CPU is
> running is being used by cyclictest. This would prevent the bounce
> between ktimersoftd and cyclictest thread when both of them are on the
> same CPU.

Nope. This is even more complex than you describe it and no, we definitely
don't want to think about this in the first place.

Thanks,

	tglx


  reply	other threads:[~2017-03-07 20:41 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-08 18:41 Regression on rt kernel while using POSIX timers Patel, Vedang
2017-02-10 19:07 ` Sebastian Andrzej Siewior
2017-02-13 18:48   ` Patel, Vedang
2017-02-15 16:54     ` bigeasy
2017-02-16  2:05       ` Julia Cartwright
2017-02-16  2:34         ` Patel, Vedang
2017-02-22  1:43           ` Patel, Vedang
2017-03-01 15:22             ` bigeasy
2017-03-01 19:03               ` Tracy Smith
2017-03-02  3:23                 ` Patel, Vedang
2017-03-03 19:41                   ` Julia Cartwright
2017-03-03 20:32                     ` Julia Cartwright
2017-03-03 21:09                     ` Thomas Gleixner
2017-03-03 23:36                       ` Patel, Vedang
2017-03-06 11:29                         ` Thomas Gleixner
2017-03-07  2:01                           ` Patel, Vedang
2017-03-07 17:03                             ` Thomas Gleixner [this message]
2017-03-20 22:54                               ` Patel, Vedang
2017-03-03 16:51                 ` Thomas Gleixner
  -- strict thread matches above, loose matches on Subject: below --
2017-02-13 20:32 Ran Shalit

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=alpine.DEB.2.20.1703071800330.3584@nanos \
    --to=tglx@linutronix.de \
    --cc=bigeasy@linutronix.de \
    --cc=darren.hart@intel.com \
    --cc=julia@ni.com \
    --cc=linux-rt-users@vger.kernel.org \
    --cc=ranshalit@gmail.com \
    --cc=tlsmith3777@gmail.com \
    --cc=vedang.patel@intel.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