From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Chris Metcalf <cmetcalf@tilera.com>,
Christoph Lameter <cl@linux.com>,
Geoff Levand <geoff@infradead.org>,
Gilad Ben Yossef <gilad@benyossef.com>,
Hakan Akkan <hakanakkan@gmail.com>,
Kevin Hilman <khilman@linaro.org>,
Li Zhong <zhong@linux.vnet.ibm.com>,
Namhyung Kim <namhyung.kim@lge.com>,
Paul Gortmaker <paul.gortmaker@windriver.com>,
Peter Zijlstra <peterz@infradead.org>,
Steven Rostedt <rostedt@goodmis.org>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [GIT PULL] nohz: Full dynticks base interface
Date: Tue, 26 Mar 2013 18:23:24 -0700 [thread overview]
Message-ID: <20130327012323.GX4379@linux.vnet.ibm.com> (raw)
In-Reply-To: <CAFTL4hxobFT_X_HMVOwB5WDHNR-YVkBjj0c2DMECPKy9goB3LQ@mail.gmail.com>
On Wed, Mar 27, 2013 at 12:48:20AM +0100, Frederic Weisbecker wrote:
> 2013/3/25 Paul E. McKenney <paulmck@linux.vnet.ibm.com>:
> > On Mon, Mar 25, 2013 at 06:12:12PM +0100, Frederic Weisbecker wrote:
> >> 2013/3/25 Paul E. McKenney <paulmck@linux.vnet.ibm.com>:
> >> > On Sun, Mar 24, 2013 at 03:46:40PM +0100, Frederic Weisbecker wrote:
> >> >> 2013/3/24 Ingo Molnar <mingo@kernel.org>:
> >> >> >
> >> >> > * Frederic Weisbecker <fweisbec@gmail.com> wrote:
> >> >> >
> >> >> >> Hi Ingo,
> >> >> >>
> >> >> >> This settles the initial ground to start a special full dynticks tree in -tip
> >> >> >> that we can iterate incrementally to accelerate the development.
> >> >> >> It is based on tip:sched/core.
> >> >> >>
> >> >> >> I tried to rearrange a bit the naming. We are probably not yet done with
> >> >> >> that but I guess we can fix it along with the rest.
> >> >> >>
> >> >> >> Please pull from:
> >> >> >>
> >> >> >> git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
> >> >> >> full-dynticks-for-mingo
> >> >> >>
> >> >> >> Changes on these commits since they were part of 3.9-rc1-nohz1:
> >> >> >>
> >> >> >> * Force a timekeeping CPU over the full dynticks range
> >> >> >> * Rename CONFIG_NO_HZ_FULL to CONFIG_NO_HZ_EXTENDED
> >> >> >> * Following *_nohz_extended_* APIs renames
> >> >> >> * Handle CPU hotplug for timekeeping
> >> >> >> * Rename full_nohz= kernel parameter to nohz_extended=
> >> >> >
> >> >> > Note that boot parameters suck for pretty much any purpose but quirks -
> >> >> > please also add a (default off!) Kconfig option to easily enable
> >> >> > nohz_extended for all CPUs.
> >> >> >
> >> >> > That way I will be able to test it automatically via randconfig and such.
> >> >>
> >> >> Sure, I'm adding such an option.
> >> >
> >> > Hmmm... This would be an option to make all but one CPU an adaptive-ticks
> >> > CPU, right? If so, this leads to the question of whether I should add a
> >> > matching no-CBs Kconfig option. My guess is "no", because the existing
> >> > CONFIG_RCU_NOCB_CPU_ALL should work just fine -- there would be a CPU that
> >> > was not an adaptive-ticks CPU, but does have its RCU callbacks offloaded.
> >> >
> >> > Or am I missing something here?
> >>
> >> No that looks right. Now I wonder if I should select
> >> CONFIG_RCU_NOCB_CPU_ALL at the same time. Probably.
> >
> > Sounds like a good initial position to me. If it somehow causes problems,
> > we can always change it later.
>
> Ah "rcu: Provide compile-time control for no-CBs CPUs" is not yet in
> -tip so I can't do that yet. Ok for now I'm going to add
> CONFIG_NO_HZ_EXTENDED_ALL and will select the matching RCU config once
> it's visible upstream.
Good point... I expect to be sending a pull request in a day or two.
Thanx, Paul
next prev parent reply other threads:[~2013-03-27 1:23 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-21 15:24 [GIT PULL] nohz: Full dynticks base interface Frederic Weisbecker
2013-03-21 15:24 ` [PATCH 1/3] nohz: Basic full dynticks interface Frederic Weisbecker
2013-03-21 15:24 ` [PATCH 2/3] nohz: Assign timekeeping duty to a CPU outside the full dynticks range Frederic Weisbecker
2013-03-21 15:24 ` [PATCH 3/3] nohz: Wake up full dynticks CPUs when a timer gets enqueued Frederic Weisbecker
2013-03-24 8:17 ` [GIT PULL] nohz: Full dynticks base interface Ingo Molnar
2013-03-24 14:46 ` Frederic Weisbecker
2013-03-25 17:02 ` Paul E. McKenney
2013-03-25 17:12 ` Frederic Weisbecker
2013-03-25 17:18 ` Paul E. McKenney
2013-03-26 23:48 ` Frederic Weisbecker
2013-03-27 1:23 ` Paul E. McKenney [this message]
2013-03-26 8:15 ` Ingo Molnar
2013-03-26 12:39 ` Frederic Weisbecker
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