From: santosh.shilimkar@ti•com (Santosh Shilimkar)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v4 1/6] Documentation: arm: define DT idle states bindings
Date: Wed, 18 Jun 2014 16:55:45 -0400 [thread overview]
Message-ID: <53A1FCD1.8070703@ti.com> (raw)
In-Reply-To: <alpine.LFD.2.11.1406181641290.16842@knanqh.ubzr>
On Wednesday 18 June 2014 04:51 PM, Nicolas Pitre wrote:
> On Wed, 18 Jun 2014, Santosh Shilimkar wrote:
>
>> On Wednesday 18 June 2014 01:36 PM, Lorenzo Pieralisi wrote:
>> [..]
>>> + To correctly specify idle states timing and energy related properties,
>>> + the following definitions identify the different execution phases
>>> + a CPU goes through to enter and exit idle states and the implied
>>> + energy metrics:
>>> +
>>> + ..__[EXEC]__|__[PREP]__|__[ENTRY]__|__[IDLE]__|__[EXIT]__|__[EXEC]__..
>>> + | | | | |
>>> +
>>> + |<------ entry ------->|
>>> + | latency |
>>> + |<- exit ->|
>>> + | latency |
>>> + |<-------- min-residency -------->|
>>> + |<------- wakeup-latency ------->|
>>> +
>> I don't know the wakeup latency makes much sense and also correct.
>> Hardware wakeup latency is actually exit latency. Is it for failed
>> or abort-able ilde case ? We are adding this as a new parameter
>> at least from idle states perspective. I think we should just
>> avoid it.
>
> I explained the rationale for this parameter in a previous email but
> Lorenzo didn't carry it over. To be clearer, this should be "worst case
> wake-up latency". It is of interest for PMQOS. This is the maximum
> delay that can be expected from the moment a wake-up event is signaled
> and the moment the CPU is back operational. This is more than just exit
> latency. By default this is entry_latency + exit_latency but when there
> is an abortable PREP phase then it may be shorter than that.
>
PMQOS angle is right. It is just that the idle code is not
going to do anything with this value. But I see a value adding it
instead of some one doing calculation.
Thanks for clarity Nico !!
regards,
Santosh
next prev parent reply other threads:[~2014-06-18 20:55 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-11 16:18 [PATCH v4 0/6] ARM generic idle states Lorenzo Pieralisi
2014-06-11 16:18 ` [PATCH v4 1/6] Documentation: arm: define DT idle states bindings Lorenzo Pieralisi
2014-06-11 18:15 ` Nicolas Pitre
2014-06-13 16:49 ` Lorenzo Pieralisi
2014-06-13 17:33 ` Nicolas Pitre
2014-06-16 14:23 ` Lorenzo Pieralisi
2014-06-16 14:48 ` Nicolas Pitre
2014-06-18 17:36 ` Lorenzo Pieralisi
2014-06-18 18:20 ` Sebastian Capella
2014-06-18 19:27 ` Santosh Shilimkar
2014-06-18 20:51 ` Nicolas Pitre
2014-06-18 20:55 ` Santosh Shilimkar [this message]
2014-06-18 21:09 ` Nicolas Pitre
2014-06-18 23:13 ` Santosh Shilimkar
2014-06-19 7:33 ` Charles Garcia-Tobin
2014-06-19 14:08 ` Santosh Shilimkar
2014-06-19 15:09 ` Charles Garcia-Tobin
2014-06-18 21:03 ` Nicolas Pitre
2014-06-13 17:40 ` Sebastian Capella
2014-06-11 16:18 ` [PATCH v4 2/6] Documentation: devicetree: psci: define CPU suspend parameter Lorenzo Pieralisi
2014-06-11 16:18 ` [PATCH v4 3/6] drivers: cpuidle: implement OF based idle states infrastructure Lorenzo Pieralisi
2014-06-11 18:24 ` Nicolas Pitre
2014-06-12 8:46 ` Lorenzo Pieralisi
2014-06-11 18:25 ` Rafael J. Wysocki
2014-06-12 9:03 ` Lorenzo Pieralisi
2014-06-13 3:48 ` Preeti U Murthy
2014-06-13 17:16 ` Lorenzo Pieralisi
2014-07-06 10:01 ` Paul Burton
2014-06-11 18:38 ` Nicolas Pitre
2014-06-12 9:19 ` Lorenzo Pieralisi
2014-06-11 16:18 ` [PATCH v4 4/6] arm64: add PSCI CPU_SUSPEND based cpu_suspend support Lorenzo Pieralisi
2014-06-11 16:18 ` [PATCH v4 5/6] drivers: cpuidle: CPU idle ARM64 driver Lorenzo Pieralisi
2014-06-18 21:34 ` Daniel Lezcano
2014-06-19 9:30 ` Lorenzo Pieralisi
2014-06-19 3:02 ` Rob Herring
2014-06-19 9:08 ` Lorenzo Pieralisi
2014-06-11 16:18 ` [PATCH v4 6/6] arm64: boot: dts: update rtsm aemv8 dts with PSCI and idle states Lorenzo Pieralisi
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