The patch titled
Track accurate idle time with tick_sched.idle_sleeptime
has been removed from the -mm tree. Its filename was
track-accurate-idle-time-with-tick_schedidle_sleeptime.patch
This patch was dropped because changes in git-acpi broke it
------------------------------------------------------
Subject: Track accurate idle time with tick_sched.idle_sleeptime
From: Venki Pallipadi <venkatesh.pallipadi@xxxxxxxxx>
Current idle time in kstat is based on jiffies and is coarse grained.
tick_sched.idle_sleeptime is making some attempt to keep track of idle time
in a fine grained manner. But, it is not handling the time spent in
interrupts fully.
Make tick_sched.idle_sleeptime accurate with respect to time spent on
handling interrupts and also add tick_sched.idle_lastupdate, which keeps
track of last time when idle_sleeptime was updated.
This statistics will be crucial for cpufreq-ondemand governor, which can
shed some conservative gaurd band that is uses today while setting the
frequency. The ondemand changes that uses the exact idle time is coming
soon.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/tick.h | 6 +++
kernel/softirq.c | 7 +++
kernel/time/tick-sched.c | 69 +++++++++++++++++++++++++------------
3 files changed, 59 insertions(+), 23 deletions(-)
diff -puN include/linux/tick.h~track-accurate-idle-time-with-tick_schedidle_sleeptime include/linux/tick.h
--- a/include/linux/tick.h~track-accurate-idle-time-with-tick_schedidle_sleeptime
+++ a/include/linux/tick.h
@@ -50,8 +50,10 @@ struct tick_sched {
unsigned long idle_jiffies;
unsigned long idle_calls;
unsigned long idle_sleeps;
+ int idle_active;
ktime_t idle_entrytime;
ktime_t idle_sleeptime;
+ ktime_t idle_lastupdate;
unsigned long last_jiffies;
unsigned long next_jiffies;
ktime_t idle_expires;
@@ -100,10 +102,14 @@ static inline int tick_check_oneshot_cha
extern void tick_nohz_stop_sched_tick(void);
extern void tick_nohz_restart_sched_tick(void);
extern void tick_nohz_update_jiffies(void);
+extern void tick_nohz_stop_idle(int cpu);
+extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time);
# else
static inline void tick_nohz_stop_sched_tick(void) { }
static inline void tick_nohz_restart_sched_tick(void) { }
static inline void tick_nohz_update_jiffies(void) { }
+static inline void tick_nohz_stop_idle(int cpu) { }
+static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return 0; }
# endif /* !NO_HZ */
#endif
diff -puN kernel/softirq.c~track-accurate-idle-time-with-tick_schedidle_sleeptime kernel/softirq.c
--- a/kernel/softirq.c~track-accurate-idle-time-with-tick_schedidle_sleeptime
+++ a/kernel/softirq.c
@@ -278,9 +278,14 @@ asmlinkage void do_softirq(void)
*/
void irq_enter(void)
{
+#ifdef CONFIG_NO_HZ
+ int cpu = smp_processor_id();
+ if (idle_cpu(cpu) && !in_interrupt())
+ tick_nohz_stop_idle(cpu);
+#endif
__irq_enter();
#ifdef CONFIG_NO_HZ
- if (idle_cpu(smp_processor_id()))
+ if (idle_cpu(cpu))
tick_nohz_update_jiffies();
#endif
}
diff -puN kernel/time/tick-sched.c~track-accurate-idle-time-with-tick_schedidle_sleeptime kernel/time/tick-sched.c
--- a/kernel/time/tick-sched.c~track-accurate-idle-time-with-tick_schedidle_sleeptime
+++ a/kernel/time/tick-sched.c
@@ -141,6 +141,43 @@ void tick_nohz_update_jiffies(void)
local_irq_restore(flags);
}
+void tick_nohz_stop_idle(int cpu)
+{
+ struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
+
+ if (ts->idle_active) {
+ ktime_t now, delta;
+ now = ktime_get();
+ delta = ktime_sub(now, ts->idle_entrytime);
+ ts->idle_lastupdate = now;
+ ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
+ ts->idle_active = 0;
+ }
+}
+
+static void tick_nohz_start_idle(int cpu)
+{
+ struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
+ ktime_t now, delta;
+
+ now = ktime_get();
+ if (ts->idle_active) {
+ delta = ktime_sub(now, ts->idle_entrytime);
+ ts->idle_lastupdate = now;
+ ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
+ }
+ ts->idle_entrytime = now;
+ ts->idle_active = 1;
+}
+
+u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time)
+{
+ struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
+
+ *last_update_time = ktime_to_us(ts->idle_lastupdate);
+ return ktime_to_us(ts->idle_sleeptime);
+}
+
/**
* tick_nohz_stop_sched_tick - stop the idle tick from the idle task
*
@@ -152,12 +189,13 @@ void tick_nohz_stop_sched_tick(void)
{
unsigned long seq, last_jiffies, next_jiffies, delta_jiffies, flags;
struct tick_sched *ts;
- ktime_t last_update, expires, now, delta;
+ ktime_t last_update, expires, now;
int cpu;
local_irq_save(flags);
cpu = smp_processor_id();
+ tick_nohz_start_idle(cpu);
ts = &per_cpu(tick_cpu_sched, cpu);
/*
@@ -189,19 +227,7 @@ void tick_nohz_stop_sched_tick(void)
}
}
- now = ktime_get();
- /*
- * When called from irq_exit we need to account the idle sleep time
- * correctly.
- */
- if (ts->tick_stopped) {
- delta = ktime_sub(now, ts->idle_entrytime);
- ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
- }
-
- ts->idle_entrytime = now;
ts->idle_calls++;
-
/* Read jiffies and the time when jiffies were updated last */
do {
seq = read_seqbegin(&xtime_lock);
@@ -316,23 +342,22 @@ void tick_nohz_restart_sched_tick(void)
int cpu = smp_processor_id();
struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
unsigned long ticks;
- ktime_t now, delta;
+ ktime_t now;
+
+ local_irq_disable();
+ tick_nohz_stop_idle(cpu);
- if (!ts->tick_stopped)
+ if (!ts->tick_stopped) {
+ local_irq_enable();
return;
+ }
/* Update jiffies first */
- now = ktime_get();
-
- local_irq_disable();
select_nohz_load_balancer(0);
+ now = ktime_get();
tick_do_update_jiffies64(now);
cpu_clear(cpu, nohz_cpu_mask);
- /* Account the idle time */
- delta = ktime_sub(now, ts->idle_entrytime);
- ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
-
/*
* We stopped the tick in idle. Update process times would miss the
* time we slept as update_process_times does only a 1 tick
_
Patches currently in -mm which might be from venkatesh.pallipadi@xxxxxxxxx are
git-acpi.patch
git-cpufreq.patch
intel_cacheinfo-misc-section-annotation-fixes.patch
intel_cacheinfo-call-cache_add_dev-from-cache_sysfs_init.patch
ich-force-hpet-make-generic-time-capable-of-switching-broadcast-timer.patch
ich-force-hpet-restructure-hpet-generic-clock-code.patch
ich-force-hpet-ich7-or-later-quirk-to-force-detect-enable.patch
ich-force-hpet-late-initialization-of-hpet-after-quirk.patch
ich-force-hpet-ich5-quirk-to-force-detect-enable.patch
ich-force-hpet-ich5-fix-a-bug-with-suspend-resume.patch
ich-force-hpet-add-ich7_0-pciid-to-quirk-list.patch
hpet-force-enable-on-vt8235-37-chipsets.patch
track-accurate-idle-time-with-tick_schedidle_sleeptime.patch
track-accurate-idle-time-with-tick_schedidle_sleeptime-fix.patch
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