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Commit 9d91a6f7 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

perf_counter tools: Handle lost events 



Make use of the new ->data_tail mechanism to tell kernel-space
about user-space draining the data stream. Emit lost events
(and display them) if they happen.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 43a21ea8

tools/perf/builtin-record.c

+16 −4
Original line number Original line Diff line number Diff line
@@ -78,10 +78,10 @@ struct mmap_data { 




static struct mmap_data		mmap_array[MAX_NR_CPUS][MAX_COUNTERS];

static struct mmap_data		mmap_array[MAX_NR_CPUS][MAX_COUNTERS];





static unsigned int mmap_read_head(struct mmap_data *md)

static unsigned long mmap_read_head(struct mmap_data *md)

{

{

	struct perf_counter_mmap_page *pc = md->base;

	struct perf_counter_mmap_page *pc = md->base;

	int head;

	long head;





	head = pc->data_head;

	head = pc->data_head;

	rmb();

	rmb();
@@ -89,6 +89,17 @@ static unsigned int mmap_read_head(struct mmap_data *md) 
	return head;

	return head;

}

}





static void mmap_write_tail(struct mmap_data *md, unsigned long tail)

{

	struct perf_counter_mmap_page *pc = md->base;



	/*

	 * ensure all reads are done before we write the tail out.

	 */

	/* mb(); */

	pc->data_tail = tail;

}



static void mmap_read(struct mmap_data *md)

static void mmap_read(struct mmap_data *md)

{

{

	unsigned int head = mmap_read_head(md);

	unsigned int head = mmap_read_head(md);
@@ -109,7 +120,7 @@ static void mmap_read(struct mmap_data *md) 
	 * In either case, truncate and restart at head.

	 * In either case, truncate and restart at head.

	 */

	 */

	diff = head - old;

	diff = head - old;

	if (diff > md->mask / 2 || diff < 0) {

	if (diff < 0) {

		struct timeval iv;

		struct timeval iv;

		unsigned long msecs;

		unsigned long msecs;
@@ -167,6 +178,7 @@ static void mmap_read(struct mmap_data *md) 
	}

	}





	md->prev = old;

	md->prev = old;

	mmap_write_tail(md, old);

}

}





static volatile int done = 0;

static volatile int done = 0;
@@ -424,7 +436,7 @@ try_again: 
	mmap_array[nr_cpu][counter].prev = 0;

	mmap_array[nr_cpu][counter].prev = 0;

	mmap_array[nr_cpu][counter].mask = mmap_pages*page_size - 1;

	mmap_array[nr_cpu][counter].mask = mmap_pages*page_size - 1;

	mmap_array[nr_cpu][counter].base = mmap(NULL, (mmap_pages+1)*page_size,

	mmap_array[nr_cpu][counter].base = mmap(NULL, (mmap_pages+1)*page_size,

			PROT_READ, MAP_SHARED, fd[nr_cpu][counter], 0);

			PROT_READ|PROT_WRITE, MAP_SHARED, fd[nr_cpu][counter], 0);

	if (mmap_array[nr_cpu][counter].base == MAP_FAILED) {

	if (mmap_array[nr_cpu][counter].base == MAP_FAILED) {

		error("failed to mmap with %d (%s)\n", errno, strerror(errno));

		error("failed to mmap with %d (%s)\n", errno, strerror(errno));

		exit(-1);

		exit(-1);

tools/perf/builtin-report.c

+28 −1
Original line number Original line Diff line number Diff line
@@ -83,6 +83,12 @@ struct period_event { 
	__u64 sample_period;

	__u64 sample_period;

};

};





struct lost_event {

	struct perf_event_header header;

	__u64 id;

	__u64 lost;

};



typedef union event_union {

typedef union event_union {

	struct perf_event_header	header;

	struct perf_event_header	header;

	struct ip_event			ip;

	struct ip_event			ip;
@@ -90,6 +96,7 @@ typedef union event_union { 
	struct comm_event		comm;

	struct comm_event		comm;

	struct fork_event		fork;

	struct fork_event		fork;

	struct period_event		period;

	struct period_event		period;

	struct lost_event		lost;

} event_t;

} event_t;





static LIST_HEAD(dsos);

static LIST_HEAD(dsos);
@@ -1068,7 +1075,8 @@ static unsigned long total = 0, 
		     total_mmap = 0,

		     total_mmap = 0,

		     total_comm = 0,

		     total_comm = 0,

		     total_fork = 0,

		     total_fork = 0,

		     total_unknown = 0;

		     total_unknown = 0,

		     total_lost = 0;





static int validate_chain(struct perf_callchain_entry *chain, event_t *event)

static int validate_chain(struct perf_callchain_entry *chain, event_t *event)

{

{
@@ -1260,6 +1268,20 @@ process_period_event(event_t *event, unsigned long offset, unsigned long head) 
	return 0;

	return 0;

}

}





static int

process_lost_event(event_t *event, unsigned long offset, unsigned long head)

{

	dprintf("%p [%p]: PERF_EVENT_LOST: id:%Ld: lost:%Ld\n",

		(void *)(offset + head),

		(void *)(long)(event->header.size),

		event->lost.id,

		event->lost.lost);



	total_lost += event->lost.lost;



	return 0;

}



static void trace_event(event_t *event)

static void trace_event(event_t *event)

{

{

	unsigned char *raw_event = (void *)event;

	unsigned char *raw_event = (void *)event;
@@ -1316,6 +1338,10 @@ process_event(event_t *event, unsigned long offset, unsigned long head) 




	case PERF_EVENT_PERIOD:

	case PERF_EVENT_PERIOD:

		return process_period_event(event, offset, head);

		return process_period_event(event, offset, head);



	case PERF_EVENT_LOST:

		return process_lost_event(event, offset, head);



	/*

	/*

	 * We dont process them right now but they are fine:

	 * We dont process them right now but they are fine:

	 */

	 */
@@ -1444,6 +1470,7 @@ more: 
	dprintf("    mmap events: %10ld\n", total_mmap);

	dprintf("    mmap events: %10ld\n", total_mmap);

	dprintf("    comm events: %10ld\n", total_comm);

	dprintf("    comm events: %10ld\n", total_comm);

	dprintf("    fork events: %10ld\n", total_fork);

	dprintf("    fork events: %10ld\n", total_fork);

	dprintf("    lost events: %10ld\n", total_lost);

	dprintf(" unknown events: %10ld\n", total_unknown);

	dprintf(" unknown events: %10ld\n", total_unknown);





	if (dump_trace)

	if (dump_trace)