@@ -104,6 +104,9 @@ struct hrtimer {
struct hrtimer_clock_base *base;
u8 state;
u8 is_rel;
+#if defined(CONFIG_PREEMPT_TRACER) || defined(CONFIG_IRQSOFF_TRACER)
+ ktime_t praecox;
+#endif
#ifdef CONFIG_TIMER_STATS
int start_pid;
void *start_site;
@@ -44,6 +44,29 @@ DEFINE_EVENT(latency_template, latency_preempt,
TP_PROTO(int ltype, cycles_t latency),
TP_ARGS(ltype, latency));
+TRACE_EVENT(latency_hrtimer_interrupt,
+
+ TP_PROTO(long long toffset, struct task_struct *task),
+
+ TP_ARGS(toffset, task),
+
+ TP_STRUCT__entry(
+ __field(long long, toffset)
+ __array(char, tcomm, TASK_COMM_LEN)
+ __field(int, tprio)
+ ),
+
+ TP_fast_assign(
+ __entry->toffset = toffset;
+ memcpy(__entry->tcomm, task != NULL ? task->comm : "<none>",
+ task != NULL ? TASK_COMM_LEN : 7);
+ __entry->tprio = task != NULL ? task->prio : -1;
+ ),
+
+ TP_printk("toffset=%lld thread=%s[%d]",
+ __entry->toffset, __entry->tcomm, __entry->tprio)
+);
+
#endif /* _TRACE_HIST_H */
/* This part must be outside protection */
@@ -53,9 +53,12 @@
#include <asm/uaccess.h>
#include <trace/events/timer.h>
+#include <trace/events/latency.h>
#include "tick-internal.h"
+static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer);
+
/*
* The timer bases:
*
@@ -960,6 +963,45 @@ static inline ktime_t hrtimer_update_lowres(struct hrtimer *timer, ktime_t tim,
return tim;
}
+static inline void latency_hrtimer_timing_start(struct hrtimer *timer,
+ struct hrtimer_clock_base *new_base,
+ ktime_t tim)
+{
+#if defined(CONFIG_PREEMPT_TRACER) || defined(CONFIG_IRQSOFF_TRACER)
+ if (unlikely(trace_latency_hrtimer_interrupt_enabled())) {
+ ktime_t now = new_base->get_time();
+
+ if (ktime_to_ns(tim) < ktime_to_ns(now))
+ timer->praecox = now;
+ else
+ timer->praecox = ktime_set(0, 0);
+ }
+#endif
+}
+
+static inline void latency_hrtimer_timing_stop(struct hrtimer *timer,
+ ktime_t basenow)
+{
+#if defined(CONFIG_PREEMPT_TRACER) || defined(CONFIG_IRQSOFF_TRACER)
+ long latency;
+
+ struct task_struct *task;
+
+ if (likely(!trace_latency_hrtimer_interrupt_enabled()))
+ return;
+
+ latency = ktime_to_ns(ktime_sub(basenow,
+ ktime_to_ns(timer->praecox) ?
+ timer->praecox : hrtimer_get_expires(timer)));
+
+ task = timer->function == hrtimer_wakeup ?
+ container_of(timer, struct hrtimer_sleeper,
+ timer)->task : NULL;
+ if (latency > 0)
+ trace_latency_hrtimer_interrupt((u64) latency, task);
+#endif
+}
+
/**
* hrtimer_start_range_ns - (re)start an hrtimer on the current CPU
* @timer: the timer to be added
@@ -992,6 +1034,8 @@ void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
timer_stats_hrtimer_set_start_info(timer);
+ latency_hrtimer_timing_start(timer, new_base, tim);
+
leftmost = enqueue_hrtimer(timer, new_base);
if (!leftmost)
goto unlock;
@@ -1284,6 +1328,8 @@ static void __hrtimer_run_queues(struct hrtimer_cpu_base *cpu_base, ktime_t now)
timer = container_of(node, struct hrtimer, node);
+ latency_hrtimer_timing_stop(timer, basenow);
+
/*
* The immediate goal for using the softexpires is
* minimizing wakeups, not running timers at the
Generate a histogram of the latencies of delayed timer offsets in nanoseconds. It shows the latency captured due to a delayed timer expire event. It happens for example when a timer misses its deadline due to disabled interrupts. A process if scheduled as a result of the timer expiration suffers this latency. The following filter(s) may be used 'hist:key=common_pid.execname:val=toffset,hitcount' 'hist:key=cpu,tcomm:val=toffset:sort=tcomm' 'hist:key=common_pid.execname,tcomm' Signed-off-by: Binoy Jayan <binoy.jayan@linaro.org> --- include/linux/hrtimer.h | 3 +++ include/trace/events/latency.h | 23 +++++++++++++++++++++ kernel/time/hrtimer.c | 46 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 72 insertions(+) -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project