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From: Sergei Shtylyov <sshtylyov@ru•mvista.com>
To: tglx@linutronix•de
Cc: linuxppc-dev@ozlabs•org, greg.weeks@timesys•com
Subject: [PATCH] PowerPC: dynamic tick support
Date: Thu, 9 Nov 2006 00:37:28 +0400	[thread overview]
Message-ID: <200611082337.28710.sshtylyov@ru.mvista.com> (raw)

Add dynamic tick support for PowerPC.

Signed-off-by: Sergei Shtylyov <sshtylyov@ru•mvista.com>

---
This patch is reworked against 2.6.18-hrt-dyntick2 patchset.

Known issues:
1) with 2.6.18-hrt-dyntick2, dynamic tick mode causes bootup slowdown after the
    HRT mode is entered (it seems to return to normal shortly);
2) with 2.6.18-rt7 (plus an extra patch to make it actually working :-) in the
   kernel preemption mode other than RT, that slowdown seems permanent (this
   was not happening with 2.6.18-rt6).

I don't have time to investigate now, so anybody interested is welcome to...
or I may even return to this if/when the time permits. :-)

 arch/powerpc/kernel/idle.c |    4 ++++
 1 files changed, 4 insertions(+)

Index: linux-2.6/arch/powerpc/kernel/idle.c
===================================================================
--- linux-2.6.orig/arch/powerpc/kernel/idle.c
+++ linux-2.6/arch/powerpc/kernel/idle.c
@@ -49,6 +49,8 @@ void cpu_idle(void)
 
 	set_thread_flag(TIF_POLLING_NRFLAG);
 	while (1) {
+		hrtimer_stop_sched_tick();
+
 		while (!need_resched() && !cpu_should_die()) {
 			ppc64_runlatch_off();
 
@@ -82,6 +84,8 @@ void cpu_idle(void)
 		ppc64_runlatch_on();
 		if (cpu_should_die())
 			cpu_die();
+
+		hrtimer_restart_sched_tick();
 		preempt_enable_no_resched();
 		schedule();
 		preempt_disable();

             reply	other threads:[~2006-11-08 20:37 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-11-08 20:37 Sergei Shtylyov [this message]
2007-03-16 22:09 ` [PATCH] PowerPC: dynamic tick support Sergei Shtylyov

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