From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: linux-kernel@vger.kernel.org, mingo@elte.hu,
laijs@cn.fujitsu.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de,
peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com,
edumazet@google.com, darren@dvhart.com, fweisbec@gmail.com,
sbw@mit.edu
Subject: Re: [PATCH RFC nohz_full 0/7] v2 Provide infrastructure for full-system idle
Date: Mon, 1 Jul 2013 09:03:14 -0700 [thread overview]
Message-ID: <20130701160314.GM3773@linux.vnet.ibm.com> (raw)
In-Reply-To: <87a9m65mv6.fsf@tassilo.jf.intel.com>
On Mon, Jul 01, 2013 at 08:19:25AM -0700, Andi Kleen wrote:
> "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> writes:
> >
> > The individual patches are as follows:
> >
> > 1. Add a CONFIG_NO_HZ_FULL_SYSIDLE Kconfig parameter to enable
> > this feature. Kernels built with CONFIG_NO_HZ_FULL_SYSIDLE=n
> > act exactly as they do today.
>
> Is this extra CONFIG option really needed? RCU already has a bewildering
> variety of CONFIG options, and no idle CONFIG is also pretty complicated.
> At some point noone will know how to configure kernels anymore if
> these non trivial, complicated trade off CONFIGs keep spreading.
>
> The facility sounds like a good thing in general. Just enable
> it implicitely with NO_HZ_SYSIDLE ?
I am guessing that you want CONFIG_NO_HZ_FULL to implicitly enable
the sysidle code so that CONFIG_NO_HZ_FULL_SYSIDLE can be eliminated.
I will be happy to take that step, but only after I gain full confidence
in the correctness and performance of the sysidle code.
> If you want a switch for testing I would advise a sysctl or sysfs knob
This would work well for the correctness part, but not for the performance
part.
Thanx, Paul
next prev parent reply other threads:[~2013-07-01 16:10 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-28 20:09 [PATCH RFC nohz_full 0/7] v2 Provide infrastructure for full-system idle Paul E. McKenney
2013-06-28 20:10 ` [PATCH RFC nohz_full v2 1/7] nohz_full: Add Kconfig parameter for scalable detection of all-idle state Paul E. McKenney
2013-06-28 20:10 ` [PATCH RFC nohz_full v2 2/7] nohz_full: Add rcu_dyntick data " Paul E. McKenney
2013-07-01 15:31 ` Josh Triplett
2013-07-01 15:52 ` Paul E. McKenney
2013-07-01 18:16 ` Josh Triplett
2013-07-01 18:23 ` Paul E. McKenney
2013-07-01 18:34 ` Josh Triplett
2013-07-01 19:16 ` Paul E. McKenney
2013-07-02 5:10 ` Mike Galbraith
2013-07-02 5:58 ` Paul E. McKenney
2013-06-28 20:10 ` [PATCH RFC nohz_full v2 3/7] nohz_full: Add per-CPU idle-state tracking Paul E. McKenney
2013-07-01 15:33 ` Josh Triplett
2013-06-28 20:10 ` [PATCH RFC nohz_full v2 4/7] nohz_full: Add full-system idle states and variables Paul E. McKenney
2013-06-28 20:10 ` [PATCH RFC nohz_full v2 5/7] nohz_full: Add full-system-idle arguments to API Paul E. McKenney
2013-06-28 20:10 ` [PATCH RFC nohz_full v2 6/7] nohz_full: Add full-system-idle state machine Paul E. McKenney
2013-07-01 16:35 ` Frederic Weisbecker
2013-07-01 18:10 ` Paul E. McKenney
2013-07-01 20:55 ` Frederic Weisbecker
2013-07-01 16:53 ` Frederic Weisbecker
2013-07-01 18:17 ` Paul E. McKenney
2013-07-01 21:38 ` Frederic Weisbecker
2013-07-01 22:51 ` Paul E. McKenney
2013-06-28 20:10 ` [PATCH RFC nohz_full v2 7/7] nohz_full: Force RCU's grace-period kthreads onto timekeeping CPU Paul E. McKenney
2013-07-01 15:19 ` [PATCH RFC nohz_full 0/7] v2 Provide infrastructure for full-system idle Andi Kleen
2013-07-01 16:03 ` Paul E. McKenney [this message]
2013-07-01 16:19 ` Andi Kleen
2013-07-01 19:19 ` Paul E. McKenney
2013-07-01 19:43 ` Christoph Lameter
2013-07-01 19:56 ` Paul E. McKenney
2013-07-01 20:24 ` Christoph Lameter
2013-07-01 20:43 ` Thomas Gleixner
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