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From: Peter Zijlstra <peterz@infradead.org>
To: Yuyang Du <yuyang.du@intel.com>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>,
	mingo@redhat.com, dietmar.eggemann@arm.com, pjt@google.com,
	bsegall@google.com, vincent.guittot@linaro.org,
	nicolas.pitre@linaro.org, mturquette@linaro.org,
	rjw@rjwysocki.net, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/7] sched: Introduce scale-invariant load tracking
Date: Fri, 10 Oct 2014 11:14:41 +0200	[thread overview]
Message-ID: <20141010091441.GF10832@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <20141008005007.GA7017@intel.com>

On Wed, Oct 08, 2014 at 08:50:07AM +0800, Yuyang Du wrote:
> Hi Morten,
> 
> Sorry for late jumping in.
> 
> The problem seems to be self-evident. But for the implementation to be
> equally attractive it needs to account for every freq change for every task,
> or anything less than that makes it less attractive.

I'm not entirely sure that is indeed required.

> But this should be very hard. Intel Architecture has limitation to capture all
> the freq changes in software and also the intel_pstate should have no
> notification.

So current Intel arch takes P-states as hints and then can mostly lower
their actual frequency, right? In this case still accounting at the
higher frequency is not a problem, the hardware conserves more power
than we know, but that's the right kind of error to have :-)

For the full automatic hardware, that's basically hardware without DVFS
capability so we should not bother at all and simply disable this
scaling.

> For every task, this makes the updating of the entire queue in load tracking
> more needed, so once again, ping maintainers for the rewrite patches, :)

Could you remind me what your latest version is; please reply to those
patches with a new email so that I can more conveniently locate it.

  parent reply	other threads:[~2014-10-10  9:14 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-22 16:24 [PATCH 0/7] sched: Scale-invariant per-entity load-tracking Morten Rasmussen
2014-09-22 16:24 ` [PATCH 1/7] sched: Introduce scale-invariant load tracking Morten Rasmussen
2014-09-25 13:48   ` Vincent Guittot
2014-09-25 17:23     ` Morten Rasmussen
2014-09-26  7:36       ` Vincent Guittot
2014-09-26  9:38         ` Morten Rasmussen
2014-10-02 20:34       ` Peter Zijlstra
2014-10-08 11:00         ` Morten Rasmussen
2014-10-08 11:21           ` Vincent Guittot
2014-10-08 13:53             ` Morten Rasmussen
2014-10-08 14:08               ` Vincent Guittot
2014-10-08 14:16                 ` Morten Rasmussen
2014-10-08 11:38         ` Vincent Guittot
2014-10-08 14:05           ` Morten Rasmussen
2014-10-10  9:07           ` Peter Zijlstra
2014-10-08  0:50   ` Yuyang Du
2014-10-08 12:54     ` Dietmar Eggemann
2014-10-10  9:16       ` Peter Zijlstra
2014-10-10  9:14     ` Peter Zijlstra [this message]
2014-09-22 16:24 ` [PATCH 2/7] cpufreq: Architecture specific callback for frequency changes Morten Rasmussen
2014-10-08  6:07   ` Mike Turquette
2014-10-08  6:26     ` [PATCH RFC 0/2] introduce capacity_ops to CFS Mike Turquette
2014-10-08  6:26       ` [PATCH RFC 1/2] sched: cfs: introduce capacity_ops Mike Turquette
2014-10-08  8:37         ` Peter Zijlstra
     [not found]           ` <20141008232836.4379.3339@quantum>
2014-10-09  9:00             ` Peter Zijlstra
     [not found]               ` <20141009173433.4379.58492@quantum>
2014-10-09 19:00                 ` Peter Zijlstra
2014-10-08  6:26       ` [PATCH RFC 2/2] cpufreq: arm_big_little: provide cpu capacity Mike Turquette
2014-10-08 15:48         ` Morten Rasmussen
     [not found]           ` <20141008223732.4379.78047@quantum>
2014-10-09  9:02             ` Peter Zijlstra
     [not found]               ` <20141009172513.4379.56718@quantum>
2014-10-09 17:38                 ` Peter Zijlstra
2014-09-22 16:24 ` [PATCH 3/7] arm: Frequency invariant scheduler load-tracking support Morten Rasmussen
2014-09-22 16:24 ` [PATCH 4/7] arm: Micro-architecture invariant load tracking support Morten Rasmussen
2014-09-22 16:24 ` [PATCH 5/7] sched: Implement usage tracking Morten Rasmussen
2014-09-22 16:24 ` [PATCH 6/7] sched: Make sched entity usage tracking scale-invariant Morten Rasmussen
2014-09-22 17:13   ` bsegall
2014-09-23 13:35     ` Morten Rasmussen
2014-10-02 21:04       ` Peter Zijlstra
2014-09-22 16:24 ` [PATCH 7/7] sched: Track sched_entity usage contributions Morten Rasmussen
2014-09-22 17:09   ` bsegall
2014-09-23 13:59     ` Morten Rasmussen

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