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Commit 2023b359 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

perf_counter: inheritable sample counters 



Redirect the output to the parent counter and put in some sanity checks.

[ Impact: new perfcounter feature - inherited sampling counters ]

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
LKML-Reference: <20090505155437.331556171@chello.nl>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 22c1558e

kernel/perf_counter.c

+30 −2
Original line number Diff line number Diff line
@@ -738,10 +738,18 @@ static void perf_counter_enable(struct perf_counter *counter) 
	spin_unlock_irq(&ctx->lock);

}



static void perf_counter_refresh(struct perf_counter *counter, int refresh)

static int perf_counter_refresh(struct perf_counter *counter, int refresh)

{

	/*

	 * not supported on inherited counters

	 */

	if (counter->hw_event.inherit)

		return -EINVAL;



	atomic_add(refresh, &counter->event_limit);

	perf_counter_enable(counter);



	return 0;

}



/*
@@ -1307,7 +1315,7 @@ static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
		perf_counter_disable_family(counter);

		break;

	case PERF_COUNTER_IOC_REFRESH:

		perf_counter_refresh(counter, arg);

		err = perf_counter_refresh(counter, arg);

		break;

	case PERF_COUNTER_IOC_RESET:

		perf_counter_reset(counter);
@@ -1814,6 +1822,12 @@ static int perf_output_begin(struct perf_output_handle *handle, 
	struct perf_mmap_data *data;

	unsigned int offset, head;



	/*

	 * For inherited counters we send all the output towards the parent.

	 */

	if (counter->parent)

		counter = counter->parent;



	rcu_read_lock();

	data = rcu_dereference(counter->data);

	if (!data)
@@ -1995,6 +2009,9 @@ static void perf_counter_output(struct perf_counter *counter, 
	if (record_type & PERF_RECORD_ADDR)

		perf_output_put(&handle, addr);



	/*

	 * XXX PERF_RECORD_GROUP vs inherited counters seems difficult.

	 */

	if (record_type & PERF_RECORD_GROUP) {

		struct perf_counter *leader, *sub;

		u64 nr = counter->nr_siblings;
@@ -2281,6 +2298,11 @@ int perf_counter_overflow(struct perf_counter *counter, 
	int events = atomic_read(&counter->event_limit);

	int ret = 0;



	/*

	 * XXX event_limit might not quite work as expected on inherited

	 * counters

	 */



	counter->pending_kill = POLL_IN;

	if (events && atomic_dec_and_test(&counter->event_limit)) {

		ret = 1;
@@ -2801,6 +2823,12 @@ perf_counter_alloc(struct perf_counter_hw_event *hw_event, 


	pmu = NULL;



	/*

	 * we currently do not support PERF_RECORD_GROUP on inherited counters

	 */

	if (hw_event->inherit && (hw_event->record_type & PERF_RECORD_GROUP))

		goto done;



	if (perf_event_raw(hw_event)) {

		pmu = hw_perf_counter_init(counter);

		goto done;