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From: Peter Zijlstra <peterz@infradead.org>
To: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Alex Shi <alex.shi@linaro.org>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Dietmar Eggemann <Dietmar.Eggemann@arm.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"mingo@kernel.org" <mingo@kernel.org>,
	"pjt@google.com" <pjt@google.com>,
	"cmetcalf@tilera.com" <cmetcalf@tilera.com>,
	"tony.luck@intel.com" <tony.luck@intel.com>,
	"preeti@linux.vnet.ibm.com" <preeti@linux.vnet.ibm.com>,
	"linaro-kernel@lists.linaro.org" <linaro-kernel@lists.linaro.org>,
	"paulmck@linux.vnet.ibm.com" <paulmck@linux.vnet.ibm.com>,
	"corbet@lwn.net" <corbet@lwn.net>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"len.brown@intel.com" <len.brown@intel.com>,
	"arjan@linux.intel.com" <arjan@linux.intel.com>,
	"amit.kucheria@linaro.org" <amit.kucheria@linaro.org>,
	"james.hogan@imgtec.com" <james.hogan@imgtec.com>,
	"schwidefsky@de.ibm.com" <schwidefsky@de.ibm.com>,
	"heiko.carstens@de.ibm.com" <heiko.carstens@de.ibm.com>
Subject: Re: [RFC] sched: CPU topology try
Date: Wed, 8 Jan 2014 14:04:07 +0100	[thread overview]
Message-ID: <20140108130407.GE31570@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20140108125228.GJ2936@e103034-lin>

On Wed, Jan 08, 2014 at 12:52:28PM +0000, Morten Rasmussen wrote:

> If I remember correctly, Alex used the rq runnable_avg_sum (in rq->avg)
> for this. It is the most obvious choice, but it takes ages to reach
> 100%.
> 
> #define LOAD_AVG_MAX_N 345
> 
> Worst case it takes 345 ms from the system is becomes fully utilized
> after a long period of idle until the rq runnable_avg_sum reaches 100%.
> 
> An unweigthed version of cfs_rq->runnable_load_avg and blocked_load_avg
> wouldn't have that delay.

Right.. not sure we want to involve blocked load on the utilization
metric, but who knows maybe that does make sense.

But yes, we need unweighted runnable_avg.

> Also, if we are changing the load balance behavior when all cpus are
> fully utilized

We already have this tipping point. See all the has_capacity bits. But
yes, it'd get more involved I suppose.

> we may need to think about cases where the load is
> hovering around the saturation threshold. But I don't think that is
> important yet.

Yah.. I'm going to wait until we have a fail case that can give us
some guidance before really pondering this though :-)

  reply	other threads:[~2014-01-08 13:04 UTC|newest]

Thread overview: 101+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-18 11:52 [RFC][PATCH v5 00/14] sched: packing tasks Vincent Guittot
2013-10-18 11:52 ` [RFC][PATCH v5 01/14] sched: add a new arch_sd_local_flags for sched_domain init Vincent Guittot
2013-11-05 14:06   ` Peter Zijlstra
2013-11-05 14:57     ` Vincent Guittot
2013-11-05 22:27       ` Peter Zijlstra
2013-11-06 10:10         ` Vincent Guittot
2013-11-06 13:53         ` Martin Schwidefsky
2013-11-06 14:08           ` Peter Zijlstra
2013-11-12 17:43             ` Dietmar Eggemann
2013-11-12 18:08               ` Peter Zijlstra
2013-11-13 15:47                 ` Dietmar Eggemann
2013-11-13 16:29                   ` Peter Zijlstra
2013-11-14 10:49                     ` Morten Rasmussen
2013-11-14 12:07                       ` Peter Zijlstra
2013-12-18 13:13         ` [RFC] sched: CPU topology try Vincent Guittot
2013-12-23 17:22           ` Dietmar Eggemann
2014-01-06 13:41             ` Vincent Guittot
2014-01-06 16:31               ` Peter Zijlstra
2014-01-07  8:32                 ` Vincent Guittot
2014-01-07 13:22                   ` Peter Zijlstra
2014-01-07 14:10                     ` Peter Zijlstra
2014-01-07 15:41                       ` Morten Rasmussen
2014-01-07 20:49                         ` Peter Zijlstra
2014-01-08  8:32                           ` Alex Shi
2014-01-08  8:37                             ` Peter Zijlstra
2014-01-08 12:52                               ` Morten Rasmussen
2014-01-08 13:04                                 ` Peter Zijlstra [this message]
2014-01-08 13:33                                   ` Morten Rasmussen
2014-01-08 12:35                           ` Morten Rasmussen
2014-01-08 12:42                             ` Peter Zijlstra
2014-01-08 12:45                             ` Peter Zijlstra
2014-01-08 13:27                               ` Morten Rasmussen
2014-01-08 13:32                                 ` Peter Zijlstra
2014-01-08 13:45                                   ` Morten Rasmussen
2014-01-07 14:11                     ` Vincent Guittot
2014-01-07 15:37                       ` Morten Rasmussen
2014-01-08  8:37                         ` Alex Shi
2014-01-06 16:28             ` Peter Zijlstra
2014-01-06 17:15               ` Morten Rasmussen
2014-01-07  9:57                 ` Peter Zijlstra
2014-01-01  5:00           ` Preeti U Murthy
2014-01-06 16:33             ` Peter Zijlstra
2014-01-06 16:37               ` Arjan van de Ven
2014-01-06 16:48                 ` Peter Zijlstra
2014-01-06 16:54                   ` Peter Zijlstra
2014-01-06 17:13                     ` Arjan van de Ven
2014-01-07 12:40             ` Vincent Guittot
2014-01-06 16:21           ` Peter Zijlstra
2014-01-07  8:22             ` Vincent Guittot
2014-01-07  9:40           ` Preeti U Murthy
2014-01-07  9:50             ` Peter Zijlstra
2014-01-07 10:39               ` Preeti U Murthy
2014-01-07 11:13                 ` Peter Zijlstra
2014-01-07 16:31                   ` Preeti U Murthy
2014-01-07 11:20                 ` Morten Rasmussen
2014-01-07 12:31                 ` Vincent Guittot
2014-01-07 16:51                   ` Preeti U Murthy
2013-10-18 11:52 ` [RFC][PATCH v5 03/14] sched: define pack buddy CPUs Vincent Guittot
2013-10-18 11:52 ` [RFC][PATCH v5 04/14] sched: do load balance only with packing cpus Vincent Guittot
2013-10-18 11:52 ` [RFC][PATCH v5 05/14] sched: add a packing level knob Vincent Guittot
2013-11-12 10:32   ` Peter Zijlstra
2013-11-12 10:44     ` Vincent Guittot
2013-11-12 10:55       ` Peter Zijlstra
2013-11-12 10:57         ` Vincent Guittot
2013-10-18 11:52 ` [RFC][PATCH v5 06/14] sched: create a new field with available capacity Vincent Guittot
2013-11-12 10:34   ` Peter Zijlstra
2013-11-12 11:05     ` Vincent Guittot
2013-10-18 11:52 ` [RFC][PATCH v5 07/14] sched: get CPU's activity statistic Vincent Guittot
2013-11-12 10:36   ` Peter Zijlstra
2013-11-12 10:41   ` Peter Zijlstra
2013-10-18 11:52 ` [RFC][PATCH v5 08/14] sched: move load idx selection in find_idlest_group Vincent Guittot
2013-11-12 10:49   ` Peter Zijlstra
2013-11-27 14:10   ` [tip:sched/core] sched/fair: Move " tip-bot for Vincent Guittot
2013-10-18 11:52 ` [RFC][PATCH v5 09/14] sched: update the packing cpu list Vincent Guittot
2013-10-18 11:52 ` [RFC][PATCH v5 10/14] sched: init this_load to max in find_idlest_group Vincent Guittot
2013-10-18 11:52 ` [RFC][PATCH v5 11/14] sched: add a SCHED_PACKING_TASKS config Vincent Guittot
2013-10-18 11:52 ` [RFC][PATCH v5 12/14] sched: create a statistic structure Vincent Guittot
2013-10-18 11:52 ` [RFC][PATCH v5 13/14] sched: differantiate idle cpu Vincent Guittot
2013-10-18 11:52 ` [RFC][PATCH v5 14/14] cpuidle: set the current wake up latency Vincent Guittot
2013-11-11 11:33 ` [RFC][PATCH v5 00/14] sched: packing tasks Catalin Marinas
2013-11-11 16:36   ` Peter Zijlstra
2013-11-11 16:39     ` Arjan van de Ven
2013-11-11 18:18       ` Catalin Marinas
2013-11-11 18:20         ` Arjan van de Ven
2013-11-12 12:06         ` Morten Rasmussen
2013-11-12 16:48         ` Arjan van de Ven
2013-11-12 23:14           ` Catalin Marinas
2013-11-13 16:13             ` Arjan van de Ven
2013-11-13 16:45               ` Catalin Marinas
2013-11-13 17:56                 ` Arjan van de Ven
2013-11-12 17:40     ` Catalin Marinas
2013-11-25 18:55     ` Daniel Lezcano
2013-11-11 16:38   ` Peter Zijlstra
2013-11-11 16:40     ` Arjan van de Ven
2013-11-12 10:36     ` Vincent Guittot
2013-11-11 16:54   ` Morten Rasmussen
2013-11-11 18:31     ` Catalin Marinas
2013-11-11 19:26       ` Arjan van de Ven
2013-11-11 22:43         ` Nicolas Pitre
2013-11-11 23:43         ` Catalin Marinas
2013-11-12 12:35   ` Vincent Guittot

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