From bae43c9945ebeef15e7952e317efb02393d3bfc7 Mon Sep 17 00:00:00 2001
From: Ingo Molnar <mingo@elte.hu>
Date: Thu, 11 Dec 2008 14:03:20 +0100
Subject: [PATCH] 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>
---
include/linux/perf_counter.h | 7 +++++--
kernel/perf_counter.c | 22 ++++++++++++++++++++++
2 files changed, 27 insertions(+), 2 deletions(-)
diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h
index 68f6e3ad531f..30c0ec8c1ee3 100644
--- a/include/linux/perf_counter.h
+++ b/include/linux/perf_counter.h
@@ -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, */
};
/*
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 0e93fea17120..a0fe8474ee29 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -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;
}