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* [PATCH] ARM: imx: always use TWD on IMX6Q
@ 2016-04-06 15:39 Sebastian Andrzej Siewior
  2016-04-12  8:04 ` Shawn Guo
  0 siblings, 1 reply; 2+ messages in thread
From: Sebastian Andrzej Siewior @ 2016-04-06 15:39 UTC (permalink / raw)
  To: linux-arm-kernel

There is no reason to limit the TWD to be used on SMP kernels only if the
hardware has it available.
On Wandboard i.MX6SOLO, running PREEMPT-RT and cyclictest I see as max
immediately after start in idle:
UP : ~90us
SMP: ~50us
UP + TWD: ~20us.
Based on this numbers I prefer the TWD over the slightly slower MXC
timer.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 arch/arm/mach-imx/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig
index 8ceda2844c4f..08bcf8fb76f2 100644
--- a/arch/arm/mach-imx/Kconfig
+++ b/arch/arm/mach-imx/Kconfig
@@ -524,7 +524,7 @@ config SOC_IMX6Q
 	bool "i.MX6 Quad/DualLite support"
 	select ARM_ERRATA_764369 if SMP
 	select HAVE_ARM_SCU if SMP
-	select HAVE_ARM_TWD if SMP
+	select HAVE_ARM_TWD
 	select PCI_DOMAINS if PCI
 	select PINCTRL_IMX6Q
 	select SOC_IMX6
-- 
2.8.0.rc3

^ permalink raw reply related	[flat|nested] 2+ messages in thread

* [PATCH] ARM: imx: always use TWD on IMX6Q
  2016-04-06 15:39 [PATCH] ARM: imx: always use TWD on IMX6Q Sebastian Andrzej Siewior
@ 2016-04-12  8:04 ` Shawn Guo
  0 siblings, 0 replies; 2+ messages in thread
From: Shawn Guo @ 2016-04-12  8:04 UTC (permalink / raw)
  To: linux-arm-kernel

On Wed, Apr 06, 2016 at 05:39:07PM +0200, Sebastian Andrzej Siewior wrote:
> There is no reason to limit the TWD to be used on SMP kernels only if the
> hardware has it available.
> On Wandboard i.MX6SOLO, running PREEMPT-RT and cyclictest I see as max
> immediately after start in idle:
> UP : ~90us
> SMP: ~50us
> UP + TWD: ~20us.
> Based on this numbers I prefer the TWD over the slightly slower MXC
> timer.
> 
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

Applied, thanks.

^ permalink raw reply	[flat|nested] 2+ messages in thread

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2016-04-06 15:39 [PATCH] ARM: imx: always use TWD on IMX6Q Sebastian Andrzej Siewior
2016-04-12  8:04 ` Shawn Guo

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