perf tools: Introduce event selectors

Out of ad-hoc code and global arrays with hard coded sizes.

This is the first step on having a library that will be first
used on regression tests in the 'perf test' tool.

[acme@felicio linux]$ size /tmp/perf.before
   text	   data	    bss	    dec	    hex	filename
1273776	  97384	5104416	6475576	 62cf38	/tmp/perf.before
[acme@felicio linux]$ size /tmp/perf.new
   text	   data	    bss	    dec	    hex	filename
1275422	  97416	1392416	2765254	 2a31c6	/tmp/perf.new

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Makefile

@@ -396,6 +396,7 @@ LIB_H += util/build-id.h
 LIB_H += util/debug.h
 LIB_H += util/debugfs.h
 LIB_H += util/event.h
+LIB_H += util/evsel.h
 LIB_H += util/exec_cmd.h
 LIB_H += util/types.h
 LIB_H += util/levenshtein.h
@@ -404,6 +405,7 @@ LIB_H += util/parse-options.h
 LIB_H += util/parse-events.h
 LIB_H += util/quote.h
 LIB_H += util/util.h
+LIB_H += util/xyarray.h
 LIB_H += util/header.h
 LIB_H += util/help.h
 LIB_H += util/session.h
@@ -433,6 +435,7 @@ LIB_OBJS += $(OUTPUT)util/ctype.o
 LIB_OBJS += $(OUTPUT)util/debugfs.o
 LIB_OBJS += $(OUTPUT)util/environment.o
 LIB_OBJS += $(OUTPUT)util/event.o
+LIB_OBJS += $(OUTPUT)util/evsel.o
 LIB_OBJS += $(OUTPUT)util/exec_cmd.o
 LIB_OBJS += $(OUTPUT)util/help.o
 LIB_OBJS += $(OUTPUT)util/levenshtein.o
@@ -470,6 +473,7 @@ LIB_OBJS += $(OUTPUT)util/sort.o
 LIB_OBJS += $(OUTPUT)util/hist.o
 LIB_OBJS += $(OUTPUT)util/probe-event.o
 LIB_OBJS += $(OUTPUT)util/util.o
+LIB_OBJS += $(OUTPUT)util/xyarray.o
 LIB_OBJS += $(OUTPUT)util/cpumap.o
 
 BUILTIN_OBJS += $(OUTPUT)builtin-annotate.o

tools/perf/builtin-record.c

@@ -18,6 +18,7 @@
 
 #include "util/header.h"
 #include "util/event.h"
+#include "util/evsel.h"
 #include "util/debug.h"
 #include "util/session.h"
 #include "util/symbol.h"
@@ -27,13 +28,13 @@
 #include <sched.h>
 #include <sys/mman.h>
 
+#define FD(e, x, y) (*(int *)xyarray__entry(e->fd, x, y))
+
 enum write_mode_t {
 	WRITE_FORCE,
 	WRITE_APPEND
 };
 
-static int			*fd[MAX_NR_CPUS][MAX_COUNTERS];
-
 static u64			user_interval			= ULLONG_MAX;
 static u64			default_interval		=      0;
 static u64			sample_type;
@@ -81,7 +82,6 @@ static struct perf_session	*session;
 static const char		*cpu_list;
 
 struct mmap_data {
-	int			counter;
 	void			*base;
 	unsigned int		mask;
 	unsigned int		prev;
@@ -229,12 +229,12 @@ static struct perf_header_attr *get_header_attr(struct perf_event_attr *a, int n
 	return h_attr;
 }
 
-static void create_counter(int counter, int cpu)
+static void create_counter(struct perf_evsel *evsel, int cpu)
 {
-	char *filter = filters[counter];
-	struct perf_event_attr *attr = attrs + counter;
+	char *filter = evsel->filter;
+	struct perf_event_attr *attr = &evsel->attr;
 	struct perf_header_attr *h_attr;
-	int track = !counter; /* only the first counter needs these */
+	int track = !evsel->idx; /* only the first counter needs these */
 	int thread_index;
 	int ret;
 	struct {
@@ -320,10 +320,9 @@ static void create_counter(int counter, int cpu)
 
 	for (thread_index = 0; thread_index < thread_num; thread_index++) {
 try_again:
-		fd[nr_cpu][counter][thread_index] = sys_perf_event_open(attr,
-				all_tids[thread_index], cpu, group_fd, 0);
+		FD(evsel, nr_cpu, thread_index) = sys_perf_event_open(attr, all_tids[thread_index], cpu, group_fd, 0);
 
-		if (fd[nr_cpu][counter][thread_index] < 0) {
+		if (FD(evsel, nr_cpu, thread_index) < 0) {
 			int err = errno;
 
 			if (err == EPERM || err == EACCES)
@@ -360,7 +359,7 @@ static void create_counter(int counter, int cpu)
 			}
 			printf("\n");
 			error("sys_perf_event_open() syscall returned with %d (%s).  /bin/dmesg may provide additional information.\n",
-					fd[nr_cpu][counter][thread_index], strerror(err));
+			      FD(evsel, nr_cpu, thread_index), strerror(err));
 
 #if defined(__i386__) || defined(__x86_64__)
 			if (attr->type == PERF_TYPE_HARDWARE && err == EOPNOTSUPP)
@@ -374,7 +373,7 @@ static void create_counter(int counter, int cpu)
 			exit(-1);
 		}
 
-		h_attr = get_header_attr(attr, counter);
+		h_attr = get_header_attr(attr, evsel->idx);
 		if (h_attr == NULL)
 			die("nomem\n");
 
@@ -385,7 +384,7 @@ static void create_counter(int counter, int cpu)
 			}
 		}
 
-		if (read(fd[nr_cpu][counter][thread_index], &read_data, sizeof(read_data)) == -1) {
+		if (read(FD(evsel, nr_cpu, thread_index), &read_data, sizeof(read_data)) == -1) {
 			perror("Unable to read perf file descriptor");
 			exit(-1);
 		}
@@ -395,43 +394,44 @@ static void create_counter(int counter, int cpu)
 			exit(-1);
 		}
 
-		assert(fd[nr_cpu][counter][thread_index] >= 0);
-		fcntl(fd[nr_cpu][counter][thread_index], F_SETFL, O_NONBLOCK);
+		assert(FD(evsel, nr_cpu, thread_index) >= 0);
+		fcntl(FD(evsel, nr_cpu, thread_index), F_SETFL, O_NONBLOCK);
 
 		/*
 		 * First counter acts as the group leader:
 		 */
 		if (group && group_fd == -1)
-			group_fd = fd[nr_cpu][counter][thread_index];
-
-		if (counter || thread_index) {
-			ret = ioctl(fd[nr_cpu][counter][thread_index],
-					PERF_EVENT_IOC_SET_OUTPUT,
-					fd[nr_cpu][0][0]);
+			group_fd = FD(evsel, nr_cpu, thread_index);
+
+		if (evsel->idx || thread_index) {
+			struct perf_evsel *first;
+			first = list_entry(evsel_list.next, struct perf_evsel, node);
+			ret = ioctl(FD(evsel, nr_cpu, thread_index),
+				    PERF_EVENT_IOC_SET_OUTPUT,
+				    FD(first, nr_cpu, 0));
 			if (ret) {
 				error("failed to set output: %d (%s)\n", errno,
 						strerror(errno));
 				exit(-1);
 			}
 		} else {
-			mmap_array[nr_cpu].counter = counter;
 			mmap_array[nr_cpu].prev = 0;
 			mmap_array[nr_cpu].mask = mmap_pages*page_size - 1;
 			mmap_array[nr_cpu].base = mmap(NULL, (mmap_pages+1)*page_size,
-				PROT_READ|PROT_WRITE, MAP_SHARED, fd[nr_cpu][counter][thread_index], 0);
+				PROT_READ | PROT_WRITE, MAP_SHARED, FD(evsel, nr_cpu, thread_index), 0);
 			if (mmap_array[nr_cpu].base == MAP_FAILED) {
 				error("failed to mmap with %d (%s)\n", errno, strerror(errno));
 				exit(-1);
 			}
 
-			event_array[nr_poll].fd = fd[nr_cpu][counter][thread_index];
+			event_array[nr_poll].fd = FD(evsel, nr_cpu, thread_index);
 			event_array[nr_poll].events = POLLIN;
 			nr_poll++;
 		}
 
 		if (filter != NULL) {
-			ret = ioctl(fd[nr_cpu][counter][thread_index],
-					PERF_EVENT_IOC_SET_FILTER, filter);
+			ret = ioctl(FD(evsel, nr_cpu, thread_index),
+				    PERF_EVENT_IOC_SET_FILTER, filter);
 			if (ret) {
 				error("failed to set filter with %d (%s)\n", errno,
 						strerror(errno));
@@ -446,11 +446,12 @@ static void create_counter(int counter, int cpu)
 
 static void open_counters(int cpu)
 {
-	int counter;
+	struct perf_evsel *pos;
 
 	group_fd = -1;
-	for (counter = 0; counter < nr_counters; counter++)
-		create_counter(counter, cpu);
+
+	list_for_each_entry(pos, &evsel_list, node)
+		create_counter(pos, cpu);
 
 	nr_cpu++;
 }
@@ -537,7 +538,7 @@ static void mmap_read_all(void)
 
 static int __cmd_record(int argc, const char **argv)
 {
-	int i, counter;
+	int i;
 	struct stat st;
 	int flags;
 	int err;
@@ -604,7 +605,7 @@ static int __cmd_record(int argc, const char **argv)
 			goto out_delete_session;
 	}
 
-	if (have_tracepoints(attrs, nr_counters))
+	if (have_tracepoints(&evsel_list))
 		perf_header__set_feat(&session->header, HEADER_TRACE_INFO);
 
 	/*
@@ -666,12 +667,6 @@ static int __cmd_record(int argc, const char **argv)
 		close(child_ready_pipe[0]);
 	}
 
-	nr_cpus = read_cpu_map(cpu_list);
-	if (nr_cpus < 1) {
-		perror("failed to collect number of CPUs");
-		return -1;
-	}
-
 	if (!system_wide && no_inherit && !cpu_list) {
 		open_counters(-1);
 	} else {
@@ -711,7 +706,7 @@ static int __cmd_record(int argc, const char **argv)
 			return err;
 		}
 
-		if (have_tracepoints(attrs, nr_counters)) {
+		if (have_tracepoints(&evsel_list)) {
 			/*
 			 * FIXME err <= 0 here actually means that
 			 * there were no tracepoints so its not really
@@ -720,8 +715,7 @@ static int __cmd_record(int argc, const char **argv)
 			 * return this more properly and also
 			 * propagate errors that now are calling die()
 			 */
-			err = event__synthesize_tracing_data(output, attrs,
-							     nr_counters,
+			err = event__synthesize_tracing_data(output, &evsel_list,
 							     process_synthesized_event,
 							     session);
 			if (err <= 0) {
@@ -795,13 +789,13 @@ static int __cmd_record(int argc, const char **argv)
 
 		if (done) {
 			for (i = 0; i < nr_cpu; i++) {
-				for (counter = 0;
-					counter < nr_counters;
-					counter++) {
+				struct perf_evsel *pos;
+
+				list_for_each_entry(pos, &evsel_list, node) {
 					for (thread = 0;
 						thread < thread_num;
 						thread++)
-						ioctl(fd[i][counter][thread],
+						ioctl(FD(pos, i, thread),
 							PERF_EVENT_IOC_DISABLE);
 				}
 			}
@@ -887,7 +881,8 @@ const struct option record_options[] = {
 
 int cmd_record(int argc, const char **argv, const char *prefix __used)
 {
-	int i, j, err = -ENOMEM;
+	int err = -ENOMEM;
+	struct perf_evsel *pos;
 
 	argc = parse_options(argc, argv, record_options, record_usage,
 			    PARSE_OPT_STOP_AT_NON_OPTION);
@@ -910,10 +905,9 @@ int cmd_record(int argc, const char **argv, const char *prefix __used)
 	if (no_buildid_cache || no_buildid)
 		disable_buildid_cache();
 
-	if (!nr_counters) {
-		nr_counters	= 1;
-		attrs[0].type	= PERF_TYPE_HARDWARE;
-		attrs[0].config = PERF_COUNT_HW_CPU_CYCLES;
+	if (list_empty(&evsel_list) && perf_evsel_list__create_default() < 0) {
+		pr_err("Not enough memory for event selector list\n");
+		goto out_symbol_exit;
 	}
 
 	if (target_pid != -1) {
@@ -933,12 +927,15 @@ int cmd_record(int argc, const char **argv, const char *prefix __used)
 		thread_num = 1;
 	}
 
-	for (i = 0; i < MAX_NR_CPUS; i++) {
-		for (j = 0; j < MAX_COUNTERS; j++) {
-			fd[i][j] = malloc(sizeof(int)*thread_num);
-			if (!fd[i][j])
-				goto out_free_fd;
-		}
+	nr_cpus = read_cpu_map(cpu_list);
+	if (nr_cpus < 1) {
+		perror("failed to collect number of CPUs");
+		return -1;
+	}
+
+	list_for_each_entry(pos, &evsel_list, node) {
+		if (perf_evsel__alloc_fd(pos, nr_cpus, thread_num) < 0)
+			goto out_free_fd;
 	}
 	event_array = malloc(
 		sizeof(struct pollfd)*MAX_NR_CPUS*MAX_COUNTERS*thread_num);
@@ -968,10 +965,8 @@ int cmd_record(int argc, const char **argv, const char *prefix __used)
 out_free_event_array:
 	free(event_array);
 out_free_fd:
-	for (i = 0; i < MAX_NR_CPUS; i++) {
-		for (j = 0; j < MAX_COUNTERS; j++)
-			free(fd[i][j]);
-	}
+	list_for_each_entry(pos, &evsel_list, node)
+		perf_evsel__free_fd(pos);
 	free(all_tids);
 	all_tids = NULL;
 out_symbol_exit:

tools/perf/util/evsel.c

+#include "evsel.h"
+#include "util.h"
+
+struct perf_evsel *perf_evsel__new(u32 type, u64 config, int idx)
+{
+	struct perf_evsel *evsel = zalloc(sizeof(*evsel));
+
+	if (evsel != NULL) {
+		evsel->idx	   = idx;
+		evsel->attr.type   = type;
+		evsel->attr.config = config;
+		INIT_LIST_HEAD(&evsel->node);
+	}
+
+	return evsel;
+}
+
+int perf_evsel__alloc_fd(struct perf_evsel *evsel, int ncpus, int nthreads)
+{
+	evsel->fd = xyarray__new(ncpus, nthreads, sizeof(int));
+	return evsel->fd != NULL ? 0 : -ENOMEM;
+}
+
+void perf_evsel__free_fd(struct perf_evsel *evsel)
+{
+	xyarray__delete(evsel->fd);
+	evsel->fd = NULL;
+}
+
+void perf_evsel__delete(struct perf_evsel *evsel)
+{
+	assert(list_empty(&evsel->node));
+	xyarray__delete(evsel->fd);
+	free(evsel);
+}

tools/perf/util/evsel.h

+#ifndef __PERF_EVSEL_H
+#define __PERF_EVSEL_H 1
+
+#include <linux/list.h>
+#include <linux/perf_event.h>
+#include "types.h"
+#include "xyarray.h"
+
+struct perf_evsel {
+	struct list_head	node;
+	struct perf_event_attr	attr;
+	char			*filter;
+	struct xyarray		*fd;
+	int			idx;
+	void			*priv;
+};
+
+struct perf_evsel *perf_evsel__new(u32 type, u64 config, int idx);
+void perf_evsel__delete(struct perf_evsel *evsel);
+
+int perf_evsel__alloc_fd(struct perf_evsel *evsel, int ncpus, int nthreads);
+void perf_evsel__free_fd(struct perf_evsel *evsel);
+
+#endif /* __PERF_EVSEL_H */

tools/perf/util/header.c

@@ -461,7 +461,7 @@ static int perf_header__adds_write(struct perf_header *self, int fd)
 
 		/* Write trace info */
 		trace_sec->offset = lseek(fd, 0, SEEK_CUR);
-		read_tracing_data(fd, attrs, nr_counters);
+		read_tracing_data(fd, &evsel_list);
 		trace_sec->size = lseek(fd, 0, SEEK_CUR) - trace_sec->offset;
 	}
 
@@ -1131,8 +1131,7 @@ int event__process_event_type(event_t *self,
 	return 0;
 }
 
-int event__synthesize_tracing_data(int fd, struct perf_event_attr *pattrs,
-				   int nb_events,
+int event__synthesize_tracing_data(int fd, struct list_head *pattrs,
 				   event__handler_t process,
 				   struct perf_session *session __unused)
 {
@@ -1143,7 +1142,7 @@ int event__synthesize_tracing_data(int fd, struct perf_event_attr *pattrs,
 	memset(&ev, 0, sizeof(ev));
 
 	ev.tracing_data.header.type = PERF_RECORD_HEADER_TRACING_DATA;
-	size = read_tracing_data_size(fd, pattrs, nb_events);
+	size = read_tracing_data_size(fd, pattrs);
 	if (size <= 0)
 		return size;
 	aligned_size = ALIGN(size, sizeof(u64));
@@ -1153,7 +1152,7 @@ int event__synthesize_tracing_data(int fd, struct perf_event_attr *pattrs,
 
 	process(&ev, NULL, session);
 
-	err = read_tracing_data(fd, pattrs, nb_events);
+	err = read_tracing_data(fd, pattrs);
 	write_padded(fd, NULL, 0, padding);
 
 	return aligned_size;

tools/perf/util/header.h

@@ -113,8 +113,7 @@ int event__synthesize_event_types(event__handler_t process,
 int event__process_event_type(event_t *self,
 			      struct perf_session *session);
 
-int event__synthesize_tracing_data(int fd, struct perf_event_attr *pattrs,
-				   int nb_events,
+int event__synthesize_tracing_data(int fd, struct list_head *pattrs,
 				   event__handler_t process,
 				   struct perf_session *session);
 int event__process_tracing_data(event_t *self,

tools/perf/util/parse-events.c

 #include "../../../include/linux/hw_breakpoint.h"
 #include "util.h"
 #include "../perf.h"
+#include "evsel.h"
 #include "parse-options.h"
 #include "parse-events.h"
 #include "exec_cmd.h"
@@ -12,8 +13,7 @@
 
 int				nr_counters;
 
-struct perf_event_attr		attrs[MAX_COUNTERS];
-char				*filters[MAX_COUNTERS];
+LIST_HEAD(evsel_list);
 
 struct event_symbol {
 	u8		type;
@@ -266,10 +266,10 @@ static char *event_cache_name(u8 cache_type, u8 cache_op, u8 cache_result)
 	return name;
 }
 
-const char *event_name(int counter)
+const char *event_name(struct perf_evsel *evsel)
 {
-	u64 config = attrs[counter].config;
-	int type = attrs[counter].type;
+	u64 config = evsel->attr.config;
+	int type = evsel->attr.type;
 
 	return __event_name(type, config);
 }
@@ -814,9 +814,6 @@ int parse_events(const struct option *opt __used, const char *str, int unset __u
 			return -1;
 
 	for (;;) {
-		if (nr_counters == MAX_COUNTERS)
-			return -1;
-
 		memset(&attr, 0, sizeof(attr));
 		ret = parse_event_symbols(&str, &attr);
 		if (ret == EVT_FAILED)
@@ -826,8 +823,13 @@ int parse_events(const struct option *opt __used, const char *str, int unset __u
 			return -1;
 
 		if (ret != EVT_HANDLED_ALL) {
-			attrs[nr_counters] = attr;
-			nr_counters++;
+			struct perf_evsel *evsel;
+			evsel = perf_evsel__new(attr.type, attr.config,
+						nr_counters);
+			if (evsel == NULL)
+				return -1;
+			list_add_tail(&evsel->node, &evsel_list);
+			++nr_counters;
 		}
 
 		if (*str == 0)
@@ -844,21 +846,22 @@ int parse_events(const struct option *opt __used, const char *str, int unset __u
 int parse_filter(const struct option *opt __used, const char *str,
 		 int unset __used)
 {
-	int i = nr_counters - 1;
-	int len = strlen(str);
+	struct perf_evsel *last = NULL;
 
-	if (i < 0 || attrs[i].type != PERF_TYPE_TRACEPOINT) {
+	if (!list_empty(&evsel_list))
+		last = list_entry(evsel_list.prev, struct perf_evsel, node);
+
+	if (last == NULL || last->attr.type != PERF_TYPE_TRACEPOINT) {
 		fprintf(stderr,
 			"-F option should follow a -e tracepoint option\n");
 		return -1;
 	}
 
-	filters[i] = malloc(len + 1);
-	if (!filters[i]) {
+	last->filter = strdup(str);
+	if (last->filter == NULL) {
 		fprintf(stderr, "not enough memory to hold filter string\n");
 		return -1;
 	}
-	strcpy(filters[i], str);
 
 	return 0;
 }
@@ -967,3 +970,15 @@ void print_events(void)
 
 	exit(129);
 }
+
+int perf_evsel_list__create_default(void)
+{
+	struct perf_evsel *evsel = perf_evsel__new(PERF_TYPE_HARDWARE,
+						   PERF_COUNT_HW_CPU_CYCLES, 0);
+	if (evsel == NULL)
+		return -ENOMEM;
+
+	list_add(&evsel->node, &evsel_list);
+	++nr_counters;
+	return 0;
+}

tools/perf/util/parse-events.h

@@ -4,6 +4,15 @@
  * Parse symbolic events/counts passed in as options:
  */
 
+#include <linux/perf_event.h>
+
+struct list_head;
+struct perf_evsel;
+
+extern struct list_head evsel_list;
+
+int perf_evsel_list__create_default(void);
+
 struct option;
 
 struct tracepoint_path {
@@ -13,14 +22,11 @@ struct tracepoint_path {
 };
 
 extern struct tracepoint_path *tracepoint_id_to_path(u64 config);
-extern bool have_tracepoints(struct perf_event_attr *pattrs, int nb_events);
+extern bool have_tracepoints(struct list_head *evsel_list);
 
 extern int			nr_counters;
 
-extern struct perf_event_attr attrs[MAX_COUNTERS];
-extern char *filters[MAX_COUNTERS];
-
-extern const char *event_name(int ctr);
+const char *event_name(struct perf_evsel *event);
 extern const char *__event_name(int type, u64 config);
 
 extern int parse_events(const struct option *opt, const char *str, int unset);
@@ -33,5 +39,4 @@ extern void print_events(void);
 extern char debugfs_path[];
 extern int valid_debugfs_mount(const char *debugfs);
 
-
 #endif /* __PERF_PARSE_EVENTS_H */

tools/perf/util/trace-event-info.c

@@ -34,11 +34,13 @@
 #include <ctype.h>
 #include <errno.h>
 #include <stdbool.h>
+#include <linux/list.h>
 #include <linux/kernel.h>
 
 #include "../perf.h"
 #include "trace-event.h"
 #include "debugfs.h"
+#include "evsel.h"
 
 #define VERSION "0.5"
 
@@ -469,16 +471,17 @@ static void read_ftrace_printk(void)
 }
 
 static struct tracepoint_path *
-get_tracepoints_path(struct perf_event_attr *pattrs, int nb_events)
+get_tracepoints_path(struct list_head *pattrs)
 {
 	struct tracepoint_path path, *ppath = &path;
-	int i, nr_tracepoints = 0;
+	struct perf_evsel *pos;
+	int nr_tracepoints = 0;
 
-	for (i = 0; i < nb_events; i++) {
-		if (pattrs[i].type != PERF_TYPE_TRACEPOINT)
+	list_for_each_entry(pos, pattrs, node) {
+		if (pos->attr.type != PERF_TYPE_TRACEPOINT)
 			continue;
 		++nr_tracepoints;
-		ppath->next = tracepoint_id_to_path(pattrs[i].config);
+		ppath->next = tracepoint_id_to_path(pos->attr.config);
 		if (!ppath->next)
 			die("%s\n", "No memory to alloc tracepoints list");
 		ppath = ppath->next;
@@ -487,21 +490,21 @@ get_tracepoints_path(struct perf_event_attr *pattrs, int nb_events)
 	return nr_tracepoints > 0 ? path.next : NULL;
 }
 
-bool have_tracepoints(struct perf_event_attr *pattrs, int nb_events)
+bool have_tracepoints(struct list_head *pattrs)
 {
-	int i;
+	struct perf_evsel *pos;
 
-	for (i = 0; i < nb_events; i++)
-		if (pattrs[i].type == PERF_TYPE_TRACEPOINT)
+	list_for_each_entry(pos, pattrs, node)
+		if (pos->attr.type == PERF_TYPE_TRACEPOINT)
 			return true;
 
 	return false;
 }
 
-int read_tracing_data(int fd, struct perf_event_attr *pattrs, int nb_events)
+int read_tracing_data(int fd, struct list_head *pattrs)
 {
 	char buf[BUFSIZ];
-	struct tracepoint_path *tps = get_tracepoints_path(pattrs, nb_events);
+	struct tracepoint_path *tps = get_tracepoints_path(pattrs);
 
 	/*
 	 * What? No tracepoints? No sense writing anything here, bail out.
@@ -545,14 +548,13 @@ int read_tracing_data(int fd, struct perf_event_attr *pattrs, int nb_events)
 	return 0;
 }
 
-ssize_t read_tracing_data_size(int fd, struct perf_event_attr *pattrs,
-			       int nb_events)
+ssize_t read_tracing_data_size(int fd, struct list_head *pattrs)
 {
 	ssize_t size;
 	int err = 0;
 
 	calc_data_size = 1;
-	err = read_tracing_data(fd, pattrs, nb_events);
+	err = read_tracing_data(fd, pattrs);
 	size = calc_data_size - 1;
 	calc_data_size = 0;
 

tools/perf/util/trace-event.h

@@ -262,9 +262,8 @@ raw_field_value(struct event *event, const char *name, void *data);
 void *raw_field_ptr(struct event *event, const char *name, void *data);
 unsigned long long eval_flag(const char *flag);
 
-int read_tracing_data(int fd, struct perf_event_attr *pattrs, int nb_events);
-ssize_t read_tracing_data_size(int fd, struct perf_event_attr *pattrs,
-			       int nb_events);
+int read_tracing_data(int fd, struct list_head *pattrs);
+ssize_t read_tracing_data_size(int fd, struct list_head *pattrs);
 
 /* taken from kernel/trace/trace.h */
 enum trace_flag_type {

tools/perf/util/xyarray.c

+#include "xyarray.h"
+#include "util.h"
+
+struct xyarray *xyarray__new(int xlen, int ylen, size_t entry_size)
+{
+	size_t row_size = ylen * entry_size;
+	struct xyarray *xy = zalloc(sizeof(*xy) + xlen * row_size);
+
+	if (xy != NULL) {
+		xy->entry_size = entry_size;
+		xy->row_size   = row_size;
+	}
+
+	return xy;
+}
+
+void xyarray__delete(struct xyarray *xy)
+{
+	free(xy);
+}

tools/perf/util/xyarray.h

+#ifndef _PERF_XYARRAY_H_
+#define _PERF_XYARRAY_H_ 1
+
+#include <sys/types.h>
+
+struct xyarray {
+	size_t row_size;
+	size_t entry_size;
+	char contents[];
+};
+
+struct xyarray *xyarray__new(int xlen, int ylen, size_t entry_size);
+void xyarray__delete(struct xyarray *xy);
+
+static inline void *xyarray__entry(struct xyarray *xy, int x, int y)
+{
+	return &xy->contents[x * xy->row_size + y * xy->entry_size];
+}
+
+#endif /* _PERF_XYARRAY_H_ */