From: Peter Zijlstra <peterz@infradead.org>
To: Arjan van de Ven <arjan@linux.intel.com>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>,
mingo@kernel.org, vincent.guittot@linaro.org,
preeti@linux.vnet.ibm.com, alex.shi@intel.com, efault@gmx.de,
pjt@google.com, len.brown@intel.com, corbet@lwn.net,
akpm@linux-foundation.org, torvalds@linux-foundation.org,
tglx@linutronix.de, catalin.marinas@arm.com,
linux-kernel@vger.kernel.org, linaro-kernel@lists.linaro.org
Subject: Re: [RFC][PATCH 0/9] sched: Power scheduler design proposal
Date: Mon, 15 Jul 2013 23:12:30 +0200 [thread overview]
Message-ID: <20130715211230.GG23818@dyad.programming.kicks-ass.net> (raw)
In-Reply-To: <20130715210650.GF23818@dyad.programming.kicks-ass.net>
On Mon, Jul 15, 2013 at 11:06:50PM +0200, Peter Zijlstra wrote:
> OK, but isn't that part of why the micro controller might not make you go
> faster even if you do program a higher P state?
>
> But yes, I understand this issue in the 'traditional' cpufreq sense. There's no
> point in ramping the speed if all you do is stall more.
>
> But I was under the impression the 'hardware' was doing this. If not then we
> need the whole go-faster and go-slower thing and places to call them and means
> to determine to call them etc.
So with the scheduler measuring cpu utilization we could say to go-faster when
u>0.8 and go-slower when u<0.75 or so. Lacking any better metrics like the
stall stuff etc.
So I understand that ondemand spends quite a lot of time 'sampling' what the
system does while the scheduler mostly already knows this. It also has problems
because of the whole sampling thing, either it samples too often and becomes
too expensive/disruptive or it samples too little and misses world+dog.
I was hoping we could do better.
next prev parent reply other threads:[~2013-07-15 21:13 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-09 15:55 Morten Rasmussen
2013-07-09 15:55 ` [RFC][PATCH 1/9] sched: Introduce power scheduler Morten Rasmussen
2013-07-09 16:48 ` Arjan van de Ven
2013-07-10 2:10 ` Arjan van de Ven
2013-07-10 11:11 ` Morten Rasmussen
2013-07-10 11:19 ` Vincent Guittot
2013-07-09 15:55 ` [RFC][PATCH 2/9] sched: Redirect update_cpu_power to sched/power.c Morten Rasmussen
2013-07-09 15:55 ` [RFC][PATCH 3/9] sched: Make select_idle_sibling() skip cpu with a cpu_power of 1 Morten Rasmussen
2013-07-09 15:55 ` [RFC][PATCH 4/9] sched: Make periodic load-balance disregard cpus " Morten Rasmussen
2013-07-09 15:55 ` [RFC][PATCH 5/9] sched: Make idle_balance() skip " Morten Rasmussen
2013-07-09 15:55 ` [RFC][PATCH 6/9] sched: power: add power_domain data structure Morten Rasmussen
2013-07-09 15:55 ` [RFC][PATCH 7/9] sched: power: Add power driver interface Morten Rasmussen
2013-07-09 15:55 ` [RFC][PATCH 8/9] sched: power: Add initial frequency scaling support to power scheduler Morten Rasmussen
2013-07-10 13:10 ` Arjan van de Ven
2013-07-12 12:51 ` Morten Rasmussen
2013-07-12 13:06 ` Catalin Marinas
2013-07-12 15:37 ` Arjan van de Ven
2013-07-09 15:55 ` [RFC][PATCH 9/9] sched: power: cpufreq: Initial schedpower cpufreq governor Morten Rasmussen
2013-07-09 16:58 ` [RFC][PATCH 0/9] sched: Power scheduler design proposal Arjan van de Ven
2013-07-10 11:16 ` Morten Rasmussen
2013-07-10 13:05 ` Arjan van de Ven
2013-07-12 12:46 ` Morten Rasmussen
2013-07-12 15:35 ` Arjan van de Ven
2013-07-12 13:00 ` Catalin Marinas
2013-07-12 15:44 ` Arjan van de Ven
2013-07-11 11:34 ` Preeti U Murthy
2013-07-12 13:48 ` Morten Rasmussen
2013-07-15 3:43 ` Preeti U Murthy
2013-07-15 9:55 ` Catalin Marinas
2013-07-15 15:24 ` Arjan van de Ven
2013-07-12 13:31 ` Catalin Marinas
2013-07-13 6:49 ` Peter Zijlstra
2013-07-13 10:23 ` Catalin Marinas
2013-07-15 7:53 ` Vincent Guittot
2013-07-15 20:39 ` Peter Zijlstra
2013-07-16 12:42 ` Catalin Marinas
2013-07-16 15:23 ` Arjan van de Ven
2013-07-17 14:14 ` Catalin Marinas
2013-07-24 13:50 ` Morten Rasmussen
2013-07-24 15:16 ` Arjan van de Ven
2013-07-24 16:46 ` Morten Rasmussen
2013-07-24 16:48 ` Arjan van de Ven
2013-07-25 8:00 ` Morten Rasmussen
2013-07-13 14:40 ` Arjan van de Ven
2013-07-15 19:59 ` Peter Zijlstra
2013-07-15 20:37 ` Arjan van de Ven
2013-07-15 21:03 ` Peter Zijlstra
2013-07-15 22:46 ` Arjan van de Ven
2013-07-16 20:45 ` David Lang
2013-07-15 20:41 ` Arjan van de Ven
2013-07-15 21:06 ` Peter Zijlstra
2013-07-15 21:12 ` Peter Zijlstra [this message]
2013-07-15 22:52 ` Arjan van de Ven
2013-07-16 17:38 ` Peter Zijlstra
2013-07-16 18:44 ` Arjan van de Ven
2013-07-16 19:21 ` Peter Zijlstra
2013-07-16 19:57 ` Arjan van de Ven
2013-07-16 20:17 ` Peter Zijlstra
2013-07-16 20:21 ` Arjan van de Ven
2013-07-16 20:32 ` Arjan van de Ven
2013-07-15 22:46 ` Arjan van de Ven
2013-07-13 16:14 ` Arjan van de Ven
2013-07-15 2:05 ` Alex Shi
2013-07-24 13:16 ` Morten Rasmussen
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