Merge branch 'perf/core' of...

Merge branch 'perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux-2.6 into perf/core

tools/perf/builtin-record.c

@@ -31,7 +31,6 @@
 #include <sys/mman.h>
 
 #define FD(e, x, y) (*(int *)xyarray__entry(e->fd, x, y))
-#define SID(e, x, y) xyarray__entry(e->id, x, y)
 
 enum write_mode_t {
 	WRITE_FORCE,
@@ -40,7 +39,6 @@ enum write_mode_t {
 
 static u64			user_interval			= ULLONG_MAX;
 static u64			default_interval		=      0;
-static u64			sample_type;
 
 static unsigned int		page_size;
 static unsigned int		mmap_pages			=    128;
@@ -160,54 +158,6 @@ static void sig_atexit(void)
 	kill(getpid(), signr);
 }
 
-static struct perf_header_attr *get_header_attr(struct perf_event_attr *a, int nr)
-{
-	struct perf_header_attr *h_attr;
-
-	if (nr < session->header.attrs) {
-		h_attr = session->header.attr[nr];
-	} else {
-		h_attr = perf_header_attr__new(a);
-		if (h_attr != NULL)
-			if (perf_header__add_attr(&session->header, h_attr) < 0) {
-				perf_header_attr__delete(h_attr);
-				h_attr = NULL;
-			}
-	}
-
-	return h_attr;
-}
-
-static void create_counter(struct perf_evsel *evsel, int cpu)
-{
-	struct perf_event_attr *attr = &evsel->attr;
-	struct perf_header_attr *h_attr;
-	struct perf_sample_id *sid;
-	int thread_index;
-
-	for (thread_index = 0; thread_index < evsel_list->threads->nr; thread_index++) {
-		h_attr = get_header_attr(attr, evsel->idx);
-		if (h_attr == NULL)
-			die("nomem\n");
-
-		if (!file_new) {
-			if (memcmp(&h_attr->attr, attr, sizeof(*attr))) {
-				fprintf(stderr, "incompatible append\n");
-				exit(-1);
-			}
-		}
-
-		sid = SID(evsel, cpu, thread_index);
-		if (perf_header_attr__add_id(h_attr, sid->id) < 0) {
-			pr_warning("Not enough memory to add id\n");
-			exit(-1);
-		}
-	}
-
-	if (!sample_type)
-		sample_type = attr->sample_type;
-}
-
 static void config_attr(struct perf_evsel *evsel, struct perf_evlist *evlist)
 {
 	struct perf_event_attr *attr = &evsel->attr;
@@ -278,10 +228,28 @@ static void config_attr(struct perf_evsel *evsel, struct perf_evlist *evlist)
 	}
 }
 
+static bool perf_evlist__equal(struct perf_evlist *evlist,
+			       struct perf_evlist *other)
+{
+	struct perf_evsel *pos, *pair;
+
+	if (evlist->nr_entries != other->nr_entries)
+		return false;
+
+	pair = list_entry(other->entries.next, struct perf_evsel, node);
+
+	list_for_each_entry(pos, &evlist->entries, node) {
+		if (memcmp(&pos->attr, &pair->attr, sizeof(pos->attr) != 0))
+			return false;
+		pair = list_entry(pair->node.next, struct perf_evsel, node);
+	}
+
+	return true;
+}
+
 static void open_counters(struct perf_evlist *evlist)
 {
 	struct perf_evsel *pos;
-	int cpu;
 
 	list_for_each_entry(pos, &evlist->entries, node) {
 		struct perf_event_attr *attr = &pos->attr;
@@ -364,10 +332,16 @@ static void open_counters(struct perf_evlist *evlist)
 	if (perf_evlist__mmap(evlist, mmap_pages, false) < 0)
 		die("failed to mmap with %d (%s)\n", errno, strerror(errno));
 
-	for (cpu = 0; cpu < evsel_list->cpus->nr; ++cpu) {
-		list_for_each_entry(pos, &evlist->entries, node)
-			create_counter(pos, cpu);
+	if (file_new)
+		session->evlist = evlist;
+	else {
+		if (!perf_evlist__equal(session->evlist, evlist)) {
+			fprintf(stderr, "incompatible append\n");
+			exit(-1);
+		}
  	}
+
+	perf_session__update_sample_type(session);
 }
 
 static int process_buildids(void)
@@ -390,7 +364,7 @@ static void atexit_header(void)
 
 		if (!no_buildid)
 			process_buildids();
-		perf_header__write(&session->header, evsel_list, output, true);
+		perf_session__write_header(session, evsel_list, output, true);
 		perf_session__delete(session);
 		perf_evlist__delete(evsel_list);
 		symbol__exit();
@@ -524,7 +498,7 @@ static int __cmd_record(int argc, const char **argv)
 		perf_header__set_feat(&session->header, HEADER_BUILD_ID);
 
 	if (!file_new) {
-		err = perf_header__read(session, output);
+		err = perf_session__read_header(session, output);
 		if (err < 0)
 			goto out_delete_session;
 	}
@@ -588,8 +562,6 @@ static int __cmd_record(int argc, const char **argv)
 
 	open_counters(evsel_list);
 
-	perf_session__set_sample_type(session, sample_type);
-
 	/*
 	 * perf_session__delete(session) will be called at atexit_header()
 	 */
@@ -600,7 +572,7 @@ static int __cmd_record(int argc, const char **argv)
 		if (err < 0)
 			return err;
 	} else if (file_new) {
-		err = perf_header__write(&session->header, evsel_list,
+		err = perf_session__write_header(session, evsel_list,
 						 output, false);
 		if (err < 0)
 			return err;
@@ -608,12 +580,9 @@ static int __cmd_record(int argc, const char **argv)
 
 	post_processing_offset = lseek(output, 0, SEEK_CUR);
 
-	perf_session__set_sample_id_all(session, sample_id_all_avail);
-
 	if (pipe_output) {
-		err = perf_event__synthesize_attrs(&session->header,
-						   process_synthesized_event,
-						   session);
+		err = perf_session__synthesize_attrs(session,
+						     process_synthesized_event);
 		if (err < 0) {
 			pr_err("Couldn't synthesize attrs.\n");
 			return err;

tools/perf/builtin-report.c

@@ -70,8 +70,8 @@ static int perf_session__add_hist_entry(struct perf_session *session,
 		 * FIXME: Propagate this back, but at least we're in a builtin,
 		 * where exit() is allowed. ;-)
 		 */
-		ui__warning("Invalid %s file, contains samples with id not in "
-			    "its header!\n", input_name);
+		ui__warning("Invalid %s file, contains samples with id %" PRIu64 " not in "
+			    "its header!\n", input_name, sample->id);
 		exit_browser(0);
 		exit(1);
 	}

tools/perf/builtin-top.c

@@ -883,7 +883,6 @@ static void start_counters(struct perf_evlist *evlist)
 static int __cmd_top(void)
 {
 	pthread_t thread;
-	struct perf_evsel *first;
 	int ret __used;
 	/*
 	 * FIXME: perf_session__new should allow passing a O_MMAP, so that all this
@@ -900,8 +899,8 @@ static int __cmd_top(void)
 		perf_event__synthesize_threads(perf_event__process, session);
 
 	start_counters(top.evlist);
-	first = list_entry(top.evlist->entries.next, struct perf_evsel, node);
-	perf_session__set_sample_type(session, first->attr.sample_type);
+	session->evlist = top.evlist;
+	perf_session__update_sample_type(session);
 
 	/* Wait for a minimal set of events before starting the snapshot */
 	poll(top.evlist->pollfd, top.evlist->nr_fds, 100);

tools/perf/util/evlist.c

@@ -19,7 +19,7 @@
 #include <linux/hash.h>
 
 #define FD(e, x, y) (*(int *)xyarray__entry(e->fd, x, y))
-#define SID(e, x, y) xyarray__entry(e->id, x, y)
+#define SID(e, x, y) xyarray__entry(e->sample_id, x, y)
 
 void perf_evlist__init(struct perf_evlist *evlist, struct cpu_map *cpus,
 		       struct thread_map *threads)
@@ -106,7 +106,8 @@ void perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd)
 	evlist->nr_fds++;
 }
 
-void perf_evlist__id_hash(struct perf_evlist *evlist, struct perf_evsel *evsel,
+static void perf_evlist__id_hash(struct perf_evlist *evlist,
+				 struct perf_evsel *evsel,
 				 int cpu, int thread, u64 id)
 {
 	int hash;
@@ -118,7 +119,14 @@ void perf_evlist__id_hash(struct perf_evlist *evlist, struct perf_evsel *evsel,
 	hlist_add_head(&sid->node, &evlist->heads[hash]);
 }
 
-static int perf_evlist__id_hash_fd(struct perf_evlist *evlist,
+void perf_evlist__id_add(struct perf_evlist *evlist, struct perf_evsel *evsel,
+			 int cpu, int thread, u64 id)
+{
+	perf_evlist__id_hash(evlist, evsel, cpu, thread, id);
+	evsel->id[evsel->ids++] = id;
+}
+
+static int perf_evlist__id_add_fd(struct perf_evlist *evlist,
 				  struct perf_evsel *evsel,
 				  int cpu, int thread, int fd)
 {
@@ -134,7 +142,7 @@ static int perf_evlist__id_hash_fd(struct perf_evlist *evlist,
 	if (evsel->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
 		++id_idx;
 
-	perf_evlist__id_hash(evlist, evsel, cpu, thread, read_data[id_idx]);
+	perf_evlist__id_add(evlist, evsel, cpu, thread, read_data[id_idx]);
 	return 0;
 }
 
@@ -292,7 +300,7 @@ int perf_evlist__mmap(struct perf_evlist *evlist, int pages, bool overwrite)
 
 	list_for_each_entry(evsel, &evlist->entries, node) {
 		if ((evsel->attr.read_format & PERF_FORMAT_ID) &&
-		    evsel->id == NULL &&
+		    evsel->sample_id == NULL &&
 		    perf_evsel__alloc_id(evsel, cpus->nr, threads->nr) < 0)
 			return -ENOMEM;
 
@@ -308,7 +316,7 @@ int perf_evlist__mmap(struct perf_evlist *evlist, int pages, bool overwrite)
 					goto out_unmap;
 
 				if ((evsel->attr.read_format & PERF_FORMAT_ID) &&
-				    perf_evlist__id_hash_fd(evlist, evsel, cpu, thread, fd) < 0)
+				    perf_evlist__id_add_fd(evlist, evsel, cpu, thread, fd) < 0)
 					goto out_unmap;
 			}
 		}

tools/perf/util/evlist.h

@@ -38,7 +38,7 @@ void perf_evlist__delete(struct perf_evlist *evlist);
 void perf_evlist__add(struct perf_evlist *evlist, struct perf_evsel *entry);
 int perf_evlist__add_default(struct perf_evlist *evlist);
 
-void perf_evlist__id_hash(struct perf_evlist *evlist, struct perf_evsel *evsel,
+void perf_evlist__id_add(struct perf_evlist *evlist, struct perf_evsel *evsel,
 			 int cpu, int thread, u64 id);
 
 int perf_evlist__alloc_pollfd(struct perf_evlist *evlist);

tools/perf/util/evsel.c

@@ -41,8 +41,18 @@ int perf_evsel__alloc_fd(struct perf_evsel *evsel, int ncpus, int nthreads)
 
 int perf_evsel__alloc_id(struct perf_evsel *evsel, int ncpus, int nthreads)
 {
-	evsel->id = xyarray__new(ncpus, nthreads, sizeof(struct perf_sample_id));
-	return evsel->id != NULL ? 0 : -ENOMEM;
+	evsel->sample_id = xyarray__new(ncpus, nthreads, sizeof(struct perf_sample_id));
+	if (evsel->sample_id == NULL)
+		return -ENOMEM;
+
+	evsel->id = zalloc(ncpus * nthreads * sizeof(u64));
+	if (evsel->id == NULL) {
+		xyarray__delete(evsel->sample_id);
+		evsel->sample_id = NULL;
+		return -ENOMEM;
+	}
+
+	return 0;
 }
 
 int perf_evsel__alloc_counts(struct perf_evsel *evsel, int ncpus)
@@ -60,7 +70,9 @@ void perf_evsel__free_fd(struct perf_evsel *evsel)
 
 void perf_evsel__free_id(struct perf_evsel *evsel)
 {
-	xyarray__delete(evsel->id);
+	xyarray__delete(evsel->sample_id);
+	evsel->sample_id = NULL;
+	free(evsel->id);
 	evsel->id = NULL;
 }
 
@@ -79,7 +91,8 @@ void perf_evsel__exit(struct perf_evsel *evsel)
 {
 	assert(list_empty(&evsel->node));
 	xyarray__delete(evsel->fd);
-	xyarray__delete(evsel->id);
+	xyarray__delete(evsel->sample_id);
+	free(evsel->id);
 }
 
 void perf_evsel__delete(struct perf_evsel *evsel)

tools/perf/util/evsel.h

@@ -49,12 +49,17 @@ struct perf_evsel {
 	struct perf_event_attr	attr;
 	char			*filter;
 	struct xyarray		*fd;
-	struct xyarray		*id;
+	struct xyarray		*sample_id;
+	u64			*id;
 	struct perf_counts	*counts;
 	int			idx;
+	int			ids;
 	struct hists		hists;
 	char			*name;
+	union {
 		void		*priv;
+		off_t		id_offset;
+	};
 	struct cgroup_sel	*cgrp;
 };
 

tools/perf/util/header.h

@@ -9,13 +9,6 @@
 
 #include <linux/bitmap.h>
 
-struct perf_header_attr {
-	struct perf_event_attr attr;
-	int ids, size;
-	u64 *id;
-	off_t id_offset;
-};
-
 enum {
 	HEADER_TRACE_INFO = 1,
 	HEADER_BUILD_ID,
@@ -46,14 +39,12 @@ struct perf_pipe_file_header {
 
 struct perf_header;
 
-int perf_file_header__read(struct perf_file_header *self,
+int perf_file_header__read(struct perf_file_header *header,
 			   struct perf_header *ph, int fd);
 
 struct perf_header {
 	int			frozen;
-	int			attrs, size;
 	bool			needs_swap;
-	struct perf_header_attr **attr;
 	s64			attr_offset;
 	u64			data_offset;
 	u64			data_size;
@@ -62,35 +53,25 @@ struct perf_header {
 	DECLARE_BITMAP(adds_features, HEADER_FEAT_BITS);
 };
 
-int perf_header__init(struct perf_header *self);
-void perf_header__exit(struct perf_header *self);
-
 struct perf_evlist;
 
-int perf_header__read(struct perf_session *session, int fd);
-int perf_header__write(struct perf_header *self, struct perf_evlist *evlist,
+int perf_session__read_header(struct perf_session *session, int fd);
+int perf_session__write_header(struct perf_session *session,
+			       struct perf_evlist *evlist,
 			       int fd, bool at_exit);
 int perf_header__write_pipe(int fd);
 
-int perf_header__add_attr(struct perf_header *self,
-			  struct perf_header_attr *attr);
-
 int perf_header__push_event(u64 id, const char *name);
 char *perf_header__find_event(u64 id);
 
-struct perf_header_attr *perf_header_attr__new(struct perf_event_attr *attr);
-void perf_header_attr__delete(struct perf_header_attr *self);
+u64 perf_evlist__sample_type(struct perf_evlist *evlist);
+bool perf_evlist__sample_id_all(const struct perf_evlist *evlist);
+void perf_header__set_feat(struct perf_header *header, int feat);
+void perf_header__clear_feat(struct perf_header *header, int feat);
+bool perf_header__has_feat(const struct perf_header *header, int feat);
 
-int perf_header_attr__add_id(struct perf_header_attr *self, u64 id);
-
-u64 perf_header__sample_type(struct perf_header *header);
-bool perf_header__sample_id_all(const struct perf_header *header);
-void perf_header__set_feat(struct perf_header *self, int feat);
-void perf_header__clear_feat(struct perf_header *self, int feat);
-bool perf_header__has_feat(const struct perf_header *self, int feat);
-
-int perf_header__process_sections(struct perf_header *self, int fd,
-				  int (*process)(struct perf_file_section *self,
+int perf_header__process_sections(struct perf_header *header, int fd,
+				  int (*process)(struct perf_file_section *section,
 						 struct perf_header *ph,
 						 int feat, int fd));
 
@@ -101,9 +82,8 @@ int build_id_cache__remove_s(const char *sbuild_id, const char *debugdir);
 int perf_event__synthesize_attr(struct perf_event_attr *attr, u16 ids, u64 *id,
 				perf_event__handler_t process,
 				struct perf_session *session);
-int perf_event__synthesize_attrs(struct perf_header *self,
-				 perf_event__handler_t process,
-				 struct perf_session *session);
+int perf_session__synthesize_attrs(struct perf_session *session,
+				   perf_event__handler_t process);
 int perf_event__process_attr(union perf_event *event, struct perf_session *session);
 
 int perf_event__synthesize_event_type(u64 event_id, char *name,

tools/perf/util/session.c

@@ -13,46 +13,6 @@
 #include "sort.h"
 #include "util.h"
 
-static int perf_session__read_evlist(struct perf_session *session)
-{
-	int i, j;
-
-	session->evlist = perf_evlist__new(NULL, NULL);
-	if (session->evlist == NULL)
-		return -ENOMEM;
-
-	for (i = 0; i < session->header.attrs; ++i) {
-		struct perf_header_attr *hattr = session->header.attr[i];
-		struct perf_evsel *evsel = perf_evsel__new(&hattr->attr, i);
-
-		if (evsel == NULL)
-			goto out_delete_evlist;
-		/*
-		 * Do it before so that if perf_evsel__alloc_id fails, this
-		 * entry gets purged too at perf_evlist__delete().
-		 */
-		perf_evlist__add(session->evlist, evsel);
-		/*
-		 * We don't have the cpu and thread maps on the header, so
-		 * for allocating the perf_sample_id table we fake 1 cpu and
-		 * hattr->ids threads.
-		 */
-		if (perf_evsel__alloc_id(evsel, 1, hattr->ids))
-			goto out_delete_evlist;
-
-		for (j = 0; j < hattr->ids; ++j)
-			perf_evlist__id_hash(session->evlist, evsel, 0, j,
-					     hattr->id[j]);
-	}
-
-	return 0;
-
-out_delete_evlist:
-	perf_evlist__delete(session->evlist);
-	session->evlist = NULL;
-	return -ENOMEM;
-}
-
 static int perf_session__open(struct perf_session *self, bool force)
 {
 	struct stat input_stat;
@@ -61,7 +21,7 @@ static int perf_session__open(struct perf_session *self, bool force)
 		self->fd_pipe = true;
 		self->fd = STDIN_FILENO;
 
-		if (perf_header__read(self, self->fd) < 0)
+		if (perf_session__read_header(self, self->fd) < 0)
 			pr_err("incompatible file format");
 
 		return 0;
@@ -93,16 +53,11 @@ static int perf_session__open(struct perf_session *self, bool force)
 		goto out_close;
 	}
 
-	if (perf_header__read(self, self->fd) < 0) {
+	if (perf_session__read_header(self, self->fd) < 0) {
 		pr_err("incompatible file format");
 		goto out_close;
 	}
 
-	if (perf_session__read_evlist(self) < 0) {
-		pr_err("Not enough memory to read the event selector list\n");
-		goto out_close;
-	}
-
 	self->size = input_stat.st_size;
 	return 0;
 
@@ -139,21 +94,10 @@ static void perf_session__id_header_size(struct perf_session *session)
        session->id_hdr_size = size;
 }
 
-void perf_session__set_sample_id_all(struct perf_session *session, bool value)
-{
-	session->sample_id_all = value;
-	perf_session__id_header_size(session);
-}
-
-void perf_session__set_sample_type(struct perf_session *session, u64 type)
-{
-	session->sample_type = type;
-}
-
 void perf_session__update_sample_type(struct perf_session *self)
 {
-	self->sample_type = perf_header__sample_type(&self->header);
-	self->sample_id_all = perf_header__sample_id_all(&self->header);
+	self->sample_type = perf_evlist__sample_type(self->evlist);
+	self->sample_id_all = perf_evlist__sample_id_all(self->evlist);
 	perf_session__id_header_size(self);
 }
 
@@ -182,9 +126,6 @@ struct perf_session *perf_session__new(const char *filename, int mode,
 	if (self == NULL)
 		goto out;
 
-	if (perf_header__init(&self->header) < 0)
-		goto out_free;
-
 	memcpy(self->filename, filename, len);
 	self->threads = RB_ROOT;
 	INIT_LIST_HEAD(&self->dead_threads);
@@ -208,6 +149,7 @@ struct perf_session *perf_session__new(const char *filename, int mode,
 	if (mode == O_RDONLY) {
 		if (perf_session__open(self, force) < 0)
 			goto out_delete;
+		perf_session__update_sample_type(self);
 	} else if (mode == O_WRONLY) {
 		/*
 		 * In O_RDONLY mode this will be performed when reading the
@@ -217,8 +159,6 @@ struct perf_session *perf_session__new(const char *filename, int mode,
 			goto out_delete;
 	}
 
-	perf_session__update_sample_type(self);
-
 	if (ops && ops->ordering_requires_timestamps &&
 	    ops->ordered_samples && !self->sample_id_all) {
 		dump_printf("WARNING: No sample_id_all support, falling back to unordered processing\n");
@@ -227,9 +167,6 @@ struct perf_session *perf_session__new(const char *filename, int mode,
 
 out:
 	return self;
-out_free:
-	free(self);
-	return NULL;
 out_delete:
 	perf_session__delete(self);
 	return NULL;
@@ -260,7 +197,6 @@ static void perf_session__delete_threads(struct perf_session *self)
 
 void perf_session__delete(struct perf_session *self)
 {
-	perf_header__exit(&self->header);
 	perf_session__destroy_kernel_maps(self);
 	perf_session__delete_dead_threads(self);
 	perf_session__delete_threads(self);

tools/perf/util/session.h

@@ -112,8 +112,6 @@ void mem_bswap_64(void *src, int byte_size);
 int perf_session__create_kernel_maps(struct perf_session *self);
 
 void perf_session__update_sample_type(struct perf_session *self);
-void perf_session__set_sample_id_all(struct perf_session *session, bool value);
-void perf_session__set_sample_type(struct perf_session *session, u64 type);
 void perf_session__remove_thread(struct perf_session *self, struct thread *th);
 
 static inline

tools/perf/util/top.c

@@ -61,6 +61,12 @@ static void rb_insert_active_sym(struct rb_root *tree, struct sym_entry *se)
 	rb_insert_color(&se->rb_node, tree);
 }
 
+#define SNPRINTF(buf, size, fmt, args...) \
+({ \
+	size_t r = snprintf(buf, size, fmt, ## args); \
+	r > size ?  size : r; \
+})
+
 size_t perf_top__header_snprintf(struct perf_top *top, char *bf, size_t size)
 {
 	struct perf_evsel *counter;
@@ -70,7 +76,7 @@ size_t perf_top__header_snprintf(struct perf_top *top, char *bf, size_t size)
 	size_t ret = 0;
 
 	if (!perf_guest) {
-		ret = snprintf(bf, size,
+		ret = SNPRINTF(bf, size,
 			       "   PerfTop:%8.0f irqs/sec  kernel:%4.1f%%"
 			       "  exact: %4.1f%% [", samples_per_sec,
 			       100.0 - (100.0 * ((samples_per_sec - ksamples_per_sec) /
@@ -81,7 +87,7 @@ size_t perf_top__header_snprintf(struct perf_top *top, char *bf, size_t size)
 		float guest_kernel_samples_per_sec = top->guest_kernel_samples / top->delay_secs;
 		float guest_us_samples_per_sec = top->guest_us_samples / top->delay_secs;
 
-		ret = snprintf(bf, size,
+		ret = SNPRINTF(bf, size,
 			       "   PerfTop:%8.0f irqs/sec  kernel:%4.1f%% us:%4.1f%%"
 			       " guest kernel:%4.1f%% guest us:%4.1f%%"
 			       " exact: %4.1f%% [", samples_per_sec,
@@ -101,38 +107,52 @@ size_t perf_top__header_snprintf(struct perf_top *top, char *bf, size_t size)
 	if (top->evlist->nr_entries == 1 || !top->display_weighted) {
 		struct perf_evsel *first;
 		first = list_entry(top->evlist->entries.next, struct perf_evsel, node);
-		ret += snprintf(bf + ret, size - ret, "%" PRIu64 "%s ",
+		ret += SNPRINTF(bf + ret, size - ret, "%" PRIu64 "%s ",
 				(uint64_t)first->attr.sample_period,
 				top->freq ? "Hz" : "");
 	}
 
 	if (!top->display_weighted) {
-		ret += snprintf(bf + ret, size - ret, "%s",
+		ret += SNPRINTF(bf + ret, size - ret, "%s",
 				event_name(top->sym_evsel));
-	} else list_for_each_entry(counter, &top->evlist->entries, node) {
-		ret += snprintf(bf + ret, size - ret, "%s%s",
-				counter->idx ? "/" : "", event_name(counter));
+	} else {
+		/*
+		 * Don't let events eat all the space. Leaving 30 bytes
+		 * for the rest should be enough.
+		 */
+		size_t last_pos = size - 30;
+
+		list_for_each_entry(counter, &top->evlist->entries, node) {
+			ret += SNPRINTF(bf + ret, size - ret, "%s%s",
+					counter->idx ? "/" : "",
+					event_name(counter));
+			if (ret > last_pos) {
+				sprintf(bf + last_pos - 3, "..");
+				ret = last_pos - 1;
+				break;
+			}
+		}
 	}
 
-	ret += snprintf(bf + ret, size - ret, "], ");
+	ret += SNPRINTF(bf + ret, size - ret, "], ");
 
 	if (top->target_pid != -1)
-		ret += snprintf(bf + ret, size - ret, " (target_pid: %d",
+		ret += SNPRINTF(bf + ret, size - ret, " (target_pid: %d",
 				top->target_pid);
 	else if (top->target_tid != -1)
-		ret += snprintf(bf + ret, size - ret, " (target_tid: %d",
+		ret += SNPRINTF(bf + ret, size - ret, " (target_tid: %d",
 				top->target_tid);
 	else
-		ret += snprintf(bf + ret, size - ret, " (all");
+		ret += SNPRINTF(bf + ret, size - ret, " (all");
 
 	if (top->cpu_list)
-		ret += snprintf(bf + ret, size - ret, ", CPU%s: %s)",
+		ret += SNPRINTF(bf + ret, size - ret, ", CPU%s: %s)",
 				top->evlist->cpus->nr > 1 ? "s" : "", top->cpu_list);
 	else {
 		if (top->target_tid != -1)
-			ret += snprintf(bf + ret, size - ret, ")");
+			ret += SNPRINTF(bf + ret, size - ret, ")");
 		else
-			ret += snprintf(bf + ret, size - ret, ", %d CPU%s)",
+			ret += SNPRINTF(bf + ret, size - ret, ", %d CPU%s)",
 					top->evlist->cpus->nr,
 					top->evlist->cpus->nr > 1 ? "s" : "");
 	}