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perf counters: implement PERF_COUNT_TASK_CLOCK 

Impact: add new perf-counter type

The 'task clock' counter counts the amount of time a task is executing,
in nanoseconds. It stops ticking when a task is scheduled out either due
to it blocking, sleeping or it being preempted.

This counter type is a Linux kernel based abstraction, it is available
even if the hardware does not support native hardware performance counters.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
hifive-unleashed-5.1
Ingo Molnar 2008-12-11 14:03:20 +01:00
parent 01b2838c42
commit bae43c9945
2 changed files with 27 additions and 2 deletions
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7
include/linux/perf_counter.h
View File

@ -50,8 +50,11 @@ enum hw_event_types {
*/
PERF_COUNT_CPU_CLOCK = -1,
PERF_COUNT_TASK_CLOCK = -2,
PERF_COUNT_PAGE_FAULTS = -3,
PERF_COUNT_CONTEXT_SWITCHES = -4,
/*
* Future software events:
*/
/* PERF_COUNT_PAGE_FAULTS = -3,
PERF_COUNT_CONTEXT_SWITCHES = -4, */
};
/*

22
kernel/perf_counter.c
View File

@ -855,6 +855,25 @@ static const struct hw_perf_counter_ops perf_ops_cpu_clock = {
.hw_perf_counter_read = cpu_clock_perf_counter_read,
};
static void task_clock_perf_counter_enable(struct perf_counter *counter)
{
}
static void task_clock_perf_counter_disable(struct perf_counter *counter)
{
}
static void task_clock_perf_counter_read(struct perf_counter *counter)
{
atomic64_counter_set(counter, current->se.sum_exec_runtime);
}
static const struct hw_perf_counter_ops perf_ops_task_clock = {
.hw_perf_counter_enable = task_clock_perf_counter_enable,
.hw_perf_counter_disable = task_clock_perf_counter_disable,
.hw_perf_counter_read = task_clock_perf_counter_read,
};
static const struct hw_perf_counter_ops *
sw_perf_counter_init(struct perf_counter *counter)
{
@ -864,6 +883,9 @@ sw_perf_counter_init(struct perf_counter *counter)
case PERF_COUNT_CPU_CLOCK:
hw_ops = &perf_ops_cpu_clock;
break;
case PERF_COUNT_TASK_CLOCK:
hw_ops = &perf_ops_task_clock;
break;
default:
break;
}