From: Tony Lindgren <tony@atomide.com>
To: santosh shilimkar <santosh.shilimkar@oracle.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>,
Stephen Warren <swarren@wwwdotorg.org>,
Thierry Reding <thierry.reding@gmail.com>,
Alexandre Courbot <gnurou@gmail.com>,
Benoit Cousson <bcousson@baylibre.com>,
Nishanth Menon <nm@ti.com>,
Santosh Shilimkar <ssantosh@kernel.org>,
Shawn Guo <shawn.guo@linaro.org>,
Sascha Hauer <kernel@pengutronix.de>,
Kukjin Kim <kgene.kim@samsung.com>,
Pankaj Dubey <pankaj.dubey@samsung.com>,
Simon Horman <horms@verge.net.au>,
Magnus Damm <magnus.damm@gmail.com>,
Linus Walleij <linus.walleij@linaro.org>,
Michal Simek <michal.simek@xilinx.com>,
Rob Herring <robh+dt@kernel.org>,
Mark Rutland <Mark.Rutland@arm.com>,
Jason Cooper <jason@lakedaemon.net>,
Thomas Gleixner <tglx@linutronix.de>,
Stefan Agner <stefan@agner.ch>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-samsung-soc@vger.kernel.org" <linux-s>
Subject: Re: [PATCH v4 13/21] ARM: omap: convert wakeupgen to stacked domains
Date: Wed, 21 Jan 2015 13:37:07 -0800 [thread overview]
Message-ID: <20150121213706.GU7718@atomide.com> (raw)
In-Reply-To: <54C019EB.5030007@oracle.com>
* santosh shilimkar <santosh.shilimkar@oracle.com> [150121 13:31]:
> On 1/21/2015 12:43 PM, Tony Lindgren wrote:
> >* santosh shilimkar <santosh.shilimkar@oracle.com> [150121 12:16]:
> >>
> >>TWD is useless on this machine since single core and TWD
> >>as know die in low power states. All the broadcast stuff
> >>is for SMP machines.
> >
> >Hmm it seems we should still use TWD during runtime and
> >swich over to the gptimer for idle states for wake-up
> >events.
> >
> Well timer wheel code don't support it so if you are serious,
> some one needs to do that. For me, it is not worth at all.
> You will have more to loose than gain with these time switching
> schemes since you have to keep 2 times alive, do switching, loose
> the idle time.
>
> All of that is to save few CPU cycles since TWD is closer
> compared to other SOC timer.
>
> Anyways I will let you fight it out but IIRC, I had a
> discussion a while back with tglx in one of the conference
> and the conclusion was it not worth doing.
> Rather TWD hardware on SOC should be made wakeup capable
> and then everything is good.
>
> Till you have support, using TWD on AM43XX will break CPUIDLE.
> Not sure if it is supported or some one cares about it. Just
> keep that aspect in mind.
Yes sure I'm aware of this. It should be easy to profile the
speed gain to see if it would make much of a difference
before starting to tinker with that.
The way I think it's possible to do would be to copy the TWD
timer value to a wake-up capable gptimer before hitting any
deeper idle state. Of course some aux timer support might be
still needed :)
Regards,
Tony
next prev parent reply other threads:[~2015-01-21 21:37 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-19 9:43 [PATCH v4 00/21] irqchip: gic: killing gic_arch_extn and co, slowly Marc Zyngier
2015-01-19 9:43 ` [PATCH v4 01/21] ARM: tegra: irq: nuke leftovers from non-DT support Marc Zyngier
2015-01-19 9:43 ` [PATCH v4 02/21] irqchip: tegra: add DT-based support for legacy interrupt controller Marc Zyngier
2015-01-20 7:51 ` Peter De Schrijver
2015-01-19 9:43 ` [PATCH v4 03/21] ARM: tegra: skip gic_arch_extn setup if DT has a LIC node Marc Zyngier
2015-01-19 9:43 ` [PATCH v4 04/21] ARM: tegra: update DTs to expose legacy interrupt controller Marc Zyngier
2015-01-19 9:43 ` [PATCH v4 05/21] DT: tegra: add binding for the " Marc Zyngier
2015-01-19 9:44 ` [PATCH v4 06/21] ARM: tegra: remove old LIC support Marc Zyngier
2015-01-19 9:44 ` [PATCH v4 07/21] genirq: Add irqchip_set_wake_parent Marc Zyngier
2015-01-19 9:44 ` [PATCH v4 08/21] irqchip: crossbar: convert dra7 crossbar to stacked domains Marc Zyngier
2015-01-19 9:44 ` [PATCH v4 09/21] DT: update ti,irq-crossbar binding Marc Zyngier
2015-01-19 9:44 ` [PATCH v4 10/21] irqchip: GIC: get rid of routable domain Marc Zyngier
2015-01-19 9:44 ` [PATCH v4 11/21] DT: arm,gic: kill arm,routable-irqs Marc Zyngier
2015-01-19 9:44 ` [PATCH v4 12/21] DT: omap4/5: add binding for the wake-up generator Marc Zyngier
2015-01-21 16:26 ` Tony Lindgren
2015-01-19 9:44 ` [PATCH v4 13/21] ARM: omap: convert wakeupgen to stacked domains Marc Zyngier
2015-01-21 16:30 ` Tony Lindgren
2015-01-21 17:22 ` Marc Zyngier
2015-01-21 18:36 ` Tony Lindgren
2015-01-21 20:12 ` santosh shilimkar
2015-01-21 20:43 ` Tony Lindgren
2015-01-21 21:28 ` santosh shilimkar
2015-01-21 21:37 ` Tony Lindgren [this message]
2015-01-19 9:44 ` [PATCH v4 14/21] ARM: imx6: convert GPC " Marc Zyngier
2015-01-19 10:47 ` Lucas Stach
2015-01-19 11:12 ` Marc Zyngier
2015-01-20 11:19 ` Shawn Guo
2015-01-19 9:44 ` [PATCH v4 15/21] ARM: exynos4/5: convert pmu wakeup " Marc Zyngier
2015-01-20 7:42 ` Pankaj Dubey
2015-01-20 9:43 ` Marc Zyngier
2015-01-19 9:44 ` [PATCH v4 16/21] DT: exynos: update PMU binding Marc Zyngier
2015-01-20 7:47 ` Pankaj Dubey
2015-01-19 9:44 ` [PATCH v4 17/21] irqchip: gic: add an entry point to set up irqchip flags Marc Zyngier
2015-01-19 9:44 ` [PATCH v4 18/21] ARM: shmobile: remove use of gic_arch_extn.irq_set_wake Marc Zyngier
2015-01-19 9:44 ` [PATCH v4 19/21] ARM: ux500: switch from gic_arch_extn to gic_set_irqchip_flags Marc Zyngier
2015-01-19 9:44 ` [PATCH v4 20/21] ARM: zynq: " Marc Zyngier
2015-01-19 9:44 ` [PATCH v4 21/21] irqchip: gic: Drop support for gic_arch_extn Marc Zyngier
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