Re: [ck] [PATCH] i386 No Idle HZ aka dynticks v051205

[Con Kolivas]

On Monday 05 December 2005 11:54, Con Kolivas wrote:
> Here is an updated rollup patch for current dynticks on i386.
>
> The main change to this version is the inclusion of Dominik's patches to
> cpufreq ondemand, acpi c-states and bus mastering which should start making
> the potential power saving features of dyntick a reality (thanks!).
> One buildfix for !CONFIG_NO_IDLE_HZ as well.
>
> If you get strange stalls with this patch then almost certainly it is a
> problem with dynticks and your apic so booting with the "noapic" option
> should fix it.
>
> Split out patches, timertop and pmstats utilities and latest patch
> available here:
> http://ck.kolivas.org/patches/dyn-ticks/
>
> FAQ:
> What Hz should I use with dynticks in the config?
> 1000 to realise the benefits of the power saving features and low latency.
>
> Should I enable timer statistics?
> Only if you're planning on using the timertop utility to help you recognise
> the biggest sources of timers currently in use to help you improve power
> savings.

Looks like this fix is needed if you are using cpufreq as modules.

Cheers,
Con

---
 kernel/dyn-tick.c |    2 ++
 1 files changed, 2 insertions(+)

Index: linux-2.6.15-rc5-dt/kernel/dyn-tick.c
===================================================================
--- linux-2.6.15-rc5-dt.orig/kernel/dyn-tick.c
+++ linux-2.6.15-rc5-dt/kernel/dyn-tick.c
@@ -122,6 +122,8 @@ void dyn_early_reprogram(unsigned int de
 	write_sequnlock_irqrestore(&xtime_lock, flags);
 }
 
+EXPORT_SYMBOL(dyn_early_reprogram);
+
 void set_dyn_tick_limits(unsigned int max_skip, unsigned int min_skip)
 {
 	if (max_skip > DYN_TICK_MAX_SKIP)

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