Thread (4 messages) read the whole thread 4 messages, 3 authors, 2015-09-16

[PATCH] arm: add cpu_idle tracepoints to arch_cpu_idle

From: Russell King - ARM Linux <hidden>
Date: 2015-09-16 16:28:34
Also in: lkml

On Wed, Sep 16, 2015 at 10:37:00PM +0800, Jisheng Zhang wrote:
Currently, if cpuidle is disabled or not supported, powertop reports
zero wakeups and zero events. This is due to the cpu_idle tracepoints
are missing.

This patch is to make cpu_idle tracepoints always available even if
cpuidle is disabled or not supported.
This seems like a hack to me.  These are cpu_idle tracepoints which
tell people when something happens in cpuidle.  If cpuidle is disabled,
then surely the tracepoints shouldn't fire.

However, I'll leave it to the tracing people to have the final word on
whether this is the right thing to do as I've very little experience
with the tracing design.
quoted hunk ↗ jump to hunk
Signed-off-by: Jisheng Zhang <redacted>
---
 arch/arm/kernel/process.c | 3 +++
 1 file changed, 3 insertions(+)
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index f192a2a..aa78e09 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -28,6 +28,7 @@
 #include <linux/random.h>
 #include <linux/hw_breakpoint.h>
 #include <linux/leds.h>
+#include <trace/events/power.h>
 
 #include <asm/processor.h>
 #include <asm/thread_notify.h>
@@ -66,11 +67,13 @@ void (*arm_pm_idle)(void);
 
 void arch_cpu_idle(void)
 {
+	trace_cpu_idle_rcuidle(1, smp_processor_id());
 	if (arm_pm_idle)
 		arm_pm_idle();
 	else
 		cpu_do_idle();
 	local_irq_enable();
+	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id());
 }
 
 void arch_cpu_idle_prepare(void)
-- 
2.5.1
-- 
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