linux-kernel - [PATCH] sched/idle/x86: add missing trace_cpu_idle to mwait

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Date:	Thu, 20 Aug 2015 12:54:39 +0800
From:	Jisheng Zhang <jszhang@...vell.com>
To:	<tglx@...utronix.de>, <mingo@...hat.com>, <hpa@...or.com>,
	<x86@...nel.org>, <len.brown@...el.com>
CC:	<linux-kernel@...r.kernel.org>, Jisheng Zhang <jszhang@...vell.com>
Subject: [PATCH] sched/idle/x86: add missing trace_cpu_idle to mwait_idle()

Commit b253149b843f ("sched/idle/x86: Restore mwait_idle() to fix boot
hangs, to improve power savings and to improve performance") restores
mwait_idle(), but the trace_cpu_idle related callings are missing,
this causes powertop on my old desktop powered by Intel Core2 E6550
reports zero wakeups and zero events.

After this patch, the powertop tool works again.

Signed-off-by: Jisheng Zhang <jszhang@...vell.com>
Fixes: b253149b843f ("sched/idle/x86: Restore mwait_idle() to ...")
---
 arch/x86/kernel/process.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 397688b..c27cad7 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -408,6 +408,7 @@ static int prefer_mwait_c1_over_halt(const struct cpuinfo_x86 *c)
 static void mwait_idle(void)
 {
 	if (!current_set_polling_and_test()) {
+		trace_cpu_idle_rcuidle(1, smp_processor_id());
 		if (this_cpu_has(X86_BUG_CLFLUSH_MONITOR)) {
 			smp_mb(); /* quirk */
 			clflush((void *)&current_thread_info()->flags);
@@ -419,6 +420,7 @@ static void mwait_idle(void)
 			__sti_mwait(0, 0);
 		else
 			local_irq_enable();
+		trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id());
 	} else {
 		local_irq_enable();
 	}
-- 
2.5.0

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