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| Started by | Steven Rostedt <rostedt@goodmis.org> |
|---|---|
| First post | 2016-07-12 16:30 +0200 |
| Last post | 2016-07-18 20:20 +0200 |
| Articles | 4 — 3 participants |
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[PATCH RT 11/20] ARM: imx: always use TWD on IMX6Q Steven Rostedt <rostedt@goodmis.org> - 2016-07-12 16:30 +0200
Re: [PATCH RT 11/20] ARM: imx: always use TWD on IMX6Q Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-07-12 22:10 +0200
Re: [PATCH RT 11/20] ARM: imx: always use TWD on IMX6Q Steven Rostedt <rostedt@goodmis.org> - 2016-07-12 22:30 +0200
Re: [PATCH RT 11/20] ARM: imx: always use TWD on IMX6Q Grygorii Strashko <grygorii.strashko@ti.com> - 2016-07-18 20:20 +0200
| From | Steven Rostedt <rostedt@goodmis.org> |
|---|---|
| Date | 2016-07-12 16:30 +0200 |
| Subject | [PATCH RT 11/20] ARM: imx: always use TWD on IMX6Q |
| Message-ID | <rU6Rc-66R-43@gated-at.bofh.it> |
4.1.27-rt31-rc1 stable review patch. If anyone has any objections, please let me know. ------------------ From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> 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> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> --- 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 3a3d3e9d7bfd..92c0cf1276fe 100644 --- a/arch/arm/mach-imx/Kconfig +++ b/arch/arm/mach-imx/Kconfig @@ -558,7 +558,7 @@ 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 -- 2.8.1
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| From | Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
|---|---|
| Date | 2016-07-12 22:10 +0200 |
| Message-ID | <rUcae-1jn-25@gated-at.bofh.it> |
| In reply to | #1441408 |
* Steven Rostedt | 2016-07-12 10:24:16 [-0400]: >4.1.27-rt31-rc1 stable review patch. >If anyone has any objections, please let me know. I don't recommend to cherry-pick this. The symbol it selects (HAVE_ARM_TWD) has "depends on SMP" in v4.1. In v4.4 there should be AM43xx which is UP and also uses the TWD so the change is simple here. Sebastian
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| From | Steven Rostedt <rostedt@goodmis.org> |
|---|---|
| Date | 2016-07-12 22:30 +0200 |
| Message-ID | <rUctA-1qV-13@gated-at.bofh.it> |
| In reply to | #1441701 |
On Tue, 12 Jul 2016 22:04:29 +0200 Sebastian Andrzej Siewior <bigeasy@linutronix.de> wrote: > * Steven Rostedt | 2016-07-12 10:24:16 [-0400]: > > >4.1.27-rt31-rc1 stable review patch. > >If anyone has any objections, please let me know. > > I don't recommend to cherry-pick this. The symbol it selects > (HAVE_ARM_TWD) has "depends on SMP" in v4.1. In v4.4 there should be > AM43xx which is UP and also uses the TWD so the change is simple here. So remove it from 4.1 and older? I can do that. -- Steve
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| From | Grygorii Strashko <grygorii.strashko@ti.com> |
|---|---|
| Date | 2016-07-18 20:20 +0200 |
| Message-ID | <rWlj4-1gf-57@gated-at.bofh.it> |
| In reply to | #1441701 |
On 07/12/2016 11:04 PM, Sebastian Andrzej Siewior wrote: > * Steven Rostedt | 2016-07-12 10:24:16 [-0400]: > >> 4.1.27-rt31-rc1 stable review patch. >> If anyone has any objections, please let me know. > > I don't recommend to cherry-pick this. The symbol it selects > (HAVE_ARM_TWD) has "depends on SMP" in v4.1. In v4.4 there should be > AM43xx which is UP and also uses the TWD so the change is simple here. > yes. AM43xx is UP and supports ARM TWD, but there could be some 'issues' in !RT case :( ARM TWD might be powered off in deep CPU Idle states and lose its context if !RT & CPUIDLE, so there are should be backup broadcast timer configured. And that can cause build issues related to tick_broadcast()->smp_cross_call(). I've solved it locally for OMAP2 only: commit 0b3e6fca4d1af4aa150d32506220f4241323a00c ^Just FYI. But may be it can be done in more generic way. regards, -grygorii
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