Messages in this thread Patch in this message | | | Date | Wed, 05 May 2010 16:11:28 +0200 | From | Ronny Tschüter <> | Subject | Re: Tracing of power:power_start events doesn't work |
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Hello,
I took a look at ftrace and tried to narrow my problem down.
1) <idle>-0 | | cpuidle_idle_call() { 1) <idle>-0 | | menu_select() { 1) <idle>-0 | 0.219 us | pm_qos_requirement(); 1) <idle>-0 | 0.219 us | tick_nohz_get_sleep_length(); 1) <idle>-0 | 0.210 us | nr_iowait_cpu(); 1) <idle>-0 | 0.213 us | this_cpu_load(); 1) <idle>-0 | 0.213 us | nr_iowait_cpu(); 1) <idle>-0 | 2.472 us | } 1) <idle>-0 | | acpi_idle_enter_simple() { 1) <idle>-0 | | lapic_timer_state_broadcast() { 1) <idle>-0 | | clockevents_notify() { 1) <idle>-0 | 0.234 us | _raw_spin_lock_irqsave(); 1) <idle>-0 | | raw_notifier_call_chain() { 1) <idle>-0 | | tick_notify() { 1) <idle>-0 | | tick_broadcast_oneshot_control() { 1) <idle>-0 | 0.237 us | _raw_spin_lock_irqsave(); 1) <idle>-0 | | clockevents_set_mode() { 1) <idle>-0 | | lapic_timer_setup() { 1) <idle>-0 | 0.222 us | native_apic_mem_read(); 1) <idle>-0 | 0.213 us | native_apic_mem_write(); 1) <idle>-0 | 0.210 us | native_apic_mem_write(); 1) <idle>-0 | 1.554 us | } 1) <idle>-0 | 2.007 us | } 1) <idle>-0 | | tick_dev_program_event() { 1) <idle>-0 | | ktime_get() { 1) <idle>-0 | 0.606 us | read_hpet(); 1) <idle>-0 | 1.053 us | } 1) <idle>-0 | | clockevents_program_event() { 1) <idle>-0 | | hpet_legacy_next_event() { 1) <idle>-0 | 1.692 us | hpet_next_event(); 1) <idle>-0 | 2.190 us | } 1) <idle>-0 | 2.664 us | } 1) <idle>-0 | 4.410 us | } 1) <idle>-0 | 0.237 us | _raw_spin_unlock_irqrestore(); 1) <idle>-0 | 8.022 us | } 1) <idle>-0 | 8.460 us | } 1) <idle>-0 | 8.943 us | } 1) <idle>-0 | 0.231 us | _raw_spin_unlock_irqrestore(); 1) <idle>-0 | + 10.296 us | } 1) <idle>-0 | + 10.734 us | } 1) <idle>-0 | | ktime_get_real() { 1) <idle>-0 | | getnstimeofday() { 1) <idle>-0 | 0.630 us | read_hpet(); 1) <idle>-0 | 1.389 us | } 1) <idle>-0 | 1.830 us | } 1) <idle>-0 | ! 3833.301 us | acpi_idle_do_entry()
Like the callgraph shows, my machine uses the cpuidle framework with menu governor and an acpi-based driver to handle idle states. Unfortunately I can't find any instrumentation for tracing power events in the cpuidle.c and processor_idle.c (acpi idle management). The following patch achieved success.
diff --git a/old/processor_idle.c b/new/processor_idle.c index cc978a8..1668d34 100644 --- a/old/processor_idle.c +++ b/new/processor_idle.c @@ -42,6 +42,7 @@ #include <linux/clockchips.h> #include <linux/cpuidle.h> #include <linux/irqflags.h> +#include <trace/events/power.h>
/* * Include the apic definitions for x86 to have the APIC timer related defines @@ -796,6 +797,18 @@ static int acpi_idle_bm_check(void) */ static inline void acpi_idle_do_entry(struct acpi_processor_cx *cx) { + switch (cx->type) { + case ACPI_STATE_C1: + trace_power_start(POWER_CSTATE, 1); + break; + case ACPI_STATE_C2: + trace_power_start(POWER_CSTATE, 2); + break; + case ACPI_STATE_C3: + trace_power_start(POWER_CSTATE, 3); + break; + } + /* Don't trace irqs off for idle */ stop_critical_timings(); if (cx->entry_method == ACPI_CSTATE_FFH) {
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