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Subject[PATCH 07/10] perf_counter: hook up the tracepoint events
Enable usage of tracepoints as perf counter events.

tracepoint event ids can be found in /debug/tracing/event/*/*/id
and (for now) are represented as -65536+id in the type field.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
include/linux/perf_counter.h | 3 +++
init/Kconfig | 5 +++++
kernel/perf_counter.c | 43 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 51 insertions(+)

Index: linux-2.6/include/linux/perf_counter.h
===================================================================
--- linux-2.6.orig/include/linux/perf_counter.h
+++ linux-2.6/include/linux/perf_counter.h
@@ -53,6 +53,8 @@ enum hw_event_types {
PERF_COUNT_PAGE_FAULTS_MAJ = -7,

PERF_SW_EVENTS_MIN = -8,
+
+ PERF_TP_EVENTS_MIN = -65536
};

/*
@@ -222,6 +224,7 @@ struct perf_counter {
struct perf_data *usrdata;
struct perf_data data[2];

+ void (*destroy)(struct perf_counter *);
struct rcu_head rcu_head;
#endif
};
Index: linux-2.6/kernel/perf_counter.c
===================================================================
--- linux-2.6.orig/kernel/perf_counter.c
+++ linux-2.6/kernel/perf_counter.c
@@ -1152,6 +1152,9 @@ static void free_counter_rcu(struct rcu_

static void free_counter(struct perf_counter *counter)
{
+ if (counter->destroy)
+ counter->destroy(counter);
+
call_rcu(&counter->rcu_head, free_counter_rcu);
}

@@ -1727,6 +1730,45 @@ static const struct hw_perf_counter_ops
.read = cpu_migrations_perf_counter_read,
};

+#ifdef CONFIG_EVENT_PROFILE
+void perf_tpcounter_event(int event_id)
+{
+ perf_swcounter_event(PERF_TP_EVENTS_MIN + event_id, 1, 1,
+ task_pt_regs(current));
+}
+
+extern int ftrace_profile_enable(int);
+extern void ftrace_profile_disable(int);
+
+static void tp_perf_counter_destroy(struct perf_counter *counter)
+{
+ int event_id = counter->hw_event.type - PERF_TP_EVENTS_MIN;
+
+ ftrace_profile_disable(event_id);
+}
+
+static const struct hw_perf_counter_ops *
+tp_perf_counter_init(struct perf_counter *counter)
+{
+ int event_id = counter->hw_event.type - PERF_TP_EVENTS_MIN;
+ int ret;
+
+ ret = ftrace_profile_enable(event_id);
+ if (ret)
+ return NULL;
+
+ counter->destroy = tp_perf_counter_destroy;
+
+ return &perf_ops_generic;
+}
+#else
+static const struct hw_perf_counter_ops *
+tp_perf_counter_init(struct perf_counter *counter)
+{
+ return NULL;
+}
+#endif
+
static const struct hw_perf_counter_ops *
sw_perf_counter_init(struct perf_counter *counter)
{
@@ -1772,6 +1814,7 @@ sw_perf_counter_init(struct perf_counter
hw_ops = &perf_ops_cpu_migrations;
break;
default:
+ hw_ops = tp_perf_counter_init(counter);
break;
}

Index: linux-2.6/init/Kconfig
===================================================================
--- linux-2.6.orig/init/Kconfig
+++ linux-2.6/init/Kconfig
@@ -945,6 +945,11 @@ config PERF_COUNTERS

Say Y if unsure.

+config EVENT_PROFILE
+ bool "Tracepoint profile sources"
+ depends on PERF_COUNTERS && EVENT_TRACER
+ default y
+
endmenu

config VM_EVENT_COUNTERS
--



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