From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
LKML <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>,
"Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>,
Rusty Russell <rusty@rustcorp.com.au>, Tejun Heo <tj@kernel.org>
Subject: Re: [RFC patch 2/5] smpboot: Provide infrastructure for percpu hotplug threads
Date: Thu, 14 Jun 2012 08:45:56 -0700 [thread overview]
Message-ID: <20120614154556.GD2458@linux.vnet.ibm.com> (raw)
In-Reply-To: <1339685789.2559.37.camel@twins>
On Thu, Jun 14, 2012 at 04:56:29PM +0200, Peter Zijlstra wrote:
> On Thu, 2012-06-14 at 07:47 -0700, Paul E. McKenney wrote:
> > RCU callback processing consumes the entire CPU in RCU_BOOST case where
> > processing runs at real-time priority. This is analogous to RT throttling
> > in the scheduler.
>
> But previously we can in non-preemptible softirq context, why would if
> behave differently when done from a RT task?
In -rt, yes, but in mainline, ksoftirqd does not run at RT prio, right?
> Also, no its not quite like the throttling, that really idles the cpu
> even if there's no SCHED_OTHER tasks to run.
Agreed, not -exactly- like throttling, but it has a broadly similar
goal, namely to prevent a given type of processing from starving
everything else in the system.
That said, why does throttling idle the CPU even if there is no other
SCHED_OTHER tasks to run?
Thanx, Paul
next prev parent reply other threads:[~2012-06-14 15:46 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-13 11:00 [RFC patch 0/5] Per cpu thread hotplug infrastructure Thomas Gleixner
2012-06-13 11:00 ` [RFC patch 2/5] smpboot: Provide infrastructure for percpu hotplug threads Thomas Gleixner
2012-06-13 18:33 ` Paul E. McKenney
2012-06-13 18:56 ` Thomas Gleixner
2012-06-14 8:08 ` Peter Zijlstra
2012-06-14 8:17 ` Peter Zijlstra
2012-06-15 1:53 ` Tejun Heo
2012-06-15 9:58 ` Peter Zijlstra
2012-06-14 8:37 ` Thomas Gleixner
2012-06-14 8:38 ` Peter Zijlstra
2012-06-13 18:57 ` Paul E. McKenney
2012-06-13 19:02 ` Thomas Gleixner
2012-06-13 19:17 ` Paul E. McKenney
2012-06-13 20:47 ` Paul E. McKenney
2012-06-14 4:51 ` Paul E. McKenney
2012-06-14 11:20 ` Thomas Gleixner
2012-06-14 12:59 ` Paul E. McKenney
2012-06-14 13:01 ` Peter Zijlstra
2012-06-14 14:47 ` Paul E. McKenney
2012-06-14 14:56 ` Peter Zijlstra
2012-06-14 15:07 ` Thomas Gleixner
2012-06-14 15:45 ` Paul E. McKenney [this message]
2012-06-14 16:20 ` Thomas Gleixner
2012-06-14 13:32 ` Thomas Gleixner
2012-06-14 13:47 ` Thomas Gleixner
2012-06-14 14:12 ` Thomas Gleixner
2012-06-14 15:01 ` Paul E. McKenney
2012-06-14 15:08 ` Thomas Gleixner
2012-06-14 14:50 ` Paul E. McKenney
2012-06-14 15:02 ` Thomas Gleixner
2012-06-14 15:38 ` Paul E. McKenney
2012-06-14 16:19 ` Thomas Gleixner
2012-06-14 16:48 ` Paul E. McKenney
2012-06-14 22:40 ` Paul E. McKenney
2012-06-14 8:31 ` Srivatsa S. Bhat
2012-06-14 8:44 ` Thomas Gleixner
2012-06-18 8:47 ` Cyrill Gorcunov
2012-06-18 8:50 ` Thomas Gleixner
2012-06-13 11:00 ` [RFC patch 1/5] kthread: Implement park/unpark facility Thomas Gleixner
2012-06-14 2:32 ` Namhyung Kim
2012-06-14 8:35 ` Thomas Gleixner
2012-06-14 8:59 ` Thomas Gleixner
2012-06-14 8:36 ` Srivatsa S. Bhat
2012-06-14 20:01 ` Silas Boyd-Wickizer
2012-06-14 20:13 ` Thomas Gleixner
2012-06-14 22:13 ` Silas Boyd-Wickizer
2012-06-15 1:44 ` Tejun Heo
2012-06-13 11:00 ` [RFC patch 3/5] softirq: Use hotplug thread infrastructure Thomas Gleixner
2012-06-13 11:00 ` [RFC patch 4/5] watchdog: " Thomas Gleixner
2012-06-13 11:00 ` [RFC patch 5/5] infiniband: ehca: " Thomas Gleixner
2012-06-18 6:30 ` Rusty Russell
2012-06-18 8:08 ` Thomas Gleixner
2012-06-24 10:29 ` Thomas Gleixner
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