diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index ad562743d769..3caca60a6ce3 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -1241,35 +1241,35 @@ struct dso *machine__findnew_kernel(struct machine *machine, const char *name,
 	return dso;
 }
 
-static void dso__set_long_name_id(struct dso *dso, const char *name, struct dso_id *id, bool name_allocated)
+static void dso__set_long_name_id(struct dso *dso, const char *name, bool name_allocated)
 {
-	struct rb_root *root = dso->root;
+	struct dsos *dsos = dso->dsos;
 
 	if (name == NULL)
 		return;
 
+	if (dsos) {
+		/*
+		 * Need to avoid re-sorting the dsos breaking by non-atomically
+		 * renaming the dso.
+		 */
+		down_write(&dsos->lock);
+	}
+
 	if (dso->long_name_allocated)
 		free((char *)dso->long_name);
 
-	if (root) {
-		rb_erase(&dso->rb_node, root);
-		/*
-		 * __dsos__findnew_link_by_longname_id() isn't guaranteed to
-		 * add it back, so a clean removal is required here.
-		 */
-		RB_CLEAR_NODE(&dso->rb_node);
-		dso->root = NULL;
-	}
-
 	dso->long_name		 = name;
 	dso->long_name_len	 = strlen(name);
 	dso->long_name_allocated = name_allocated;
 
-	if (root)
-		__dsos__findnew_link_by_longname_id(root, dso, NULL, id);
+	if (dsos) {
+		dsos->sorted = false;
+		up_write(&dsos->lock);
+	}
 }
 
-static int __dso_id__cmp(struct dso_id *a, struct dso_id *b)
+static int __dso_id__cmp(const struct dso_id *a, const struct dso_id *b)
 {
 	if (a->maj > b->maj) return -1;
 	if (a->maj < b->maj) return 1;
@@ -1297,7 +1297,7 @@ static int __dso_id__cmp(struct dso_id *a, struct dso_id *b)
 	return 0;
 }
 
-bool dso_id__empty(struct dso_id *id)
+bool dso_id__empty(const struct dso_id *id)
 {
 	if (!id)
 		return true;
@@ -1305,15 +1305,22 @@ bool dso_id__empty(struct dso_id *id)
 	return !id->maj && !id->min && !id->ino && !id->ino_generation;
 }
 
-void dso__inject_id(struct dso *dso, struct dso_id *id)
+void __dso__inject_id(struct dso *dso, struct dso_id *id)
 {
+	struct dsos *dsos = dso->dsos;
+
+	/* dsos write lock held by caller. */
+
 	dso->id.maj = id->maj;
 	dso->id.min = id->min;
 	dso->id.ino = id->ino;
 	dso->id.ino_generation = id->ino_generation;
+
+	if (dsos)
+		dsos->sorted = false;
 }
 
-int dso_id__cmp(struct dso_id *a, struct dso_id *b)
+int dso_id__cmp(const struct dso_id *a, const struct dso_id *b)
 {
 	/*
 	 * The second is always dso->id, so zeroes if not set, assume passing
@@ -1332,20 +1339,34 @@ int dso__cmp_id(struct dso *a, struct dso *b)
 
 void dso__set_long_name(struct dso *dso, const char *name, bool name_allocated)
 {
-	dso__set_long_name_id(dso, name, NULL, name_allocated);
+	dso__set_long_name_id(dso, name, name_allocated);
 }
 
 void dso__set_short_name(struct dso *dso, const char *name, bool name_allocated)
 {
+	struct dsos *dsos = dso->dsos;
+
 	if (name == NULL)
 		return;
 
+	if (dsos) {
+		/*
+		 * Need to avoid re-sorting the dsos breaking by non-atomically
+		 * renaming the dso.
+		 */
+		down_write(&dsos->lock);
+	}
 	if (dso->short_name_allocated)
 		free((char *)dso->short_name);
 
 	dso->short_name		  = name;
 	dso->short_name_len	  = strlen(name);
 	dso->short_name_allocated = name_allocated;
+
+	if (dsos) {
+		dsos->sorted = false;
+		up_write(&dsos->lock);
+	}
 }
 
 int dso__name_len(const struct dso *dso)
@@ -1381,7 +1402,7 @@ struct dso *dso__new_id(const char *name, struct dso_id *id)
 		strcpy(dso->name, name);
 		if (id)
 			dso->id = *id;
-		dso__set_long_name_id(dso, dso->name, id, false);
+		dso__set_long_name_id(dso, dso->name, false);
 		dso__set_short_name(dso, dso->name, false);
 		dso->symbols = RB_ROOT_CACHED;
 		dso->symbol_names = NULL;
@@ -1406,9 +1427,6 @@ struct dso *dso__new_id(const char *name, struct dso_id *id)
 		dso->is_kmod = 0;
 		dso->needs_swap = DSO_SWAP__UNSET;
 		dso->comp = COMP_ID__NONE;
-		RB_CLEAR_NODE(&dso->rb_node);
-		dso->root = NULL;
-		INIT_LIST_HEAD(&dso->node);
 		INIT_LIST_HEAD(&dso->data.open_entry);
 		mutex_init(&dso->lock);
 		refcount_set(&dso->refcnt, 1);
@@ -1424,9 +1442,8 @@ struct dso *dso__new(const char *name)
 
 void dso__delete(struct dso *dso)
 {
-	if (!RB_EMPTY_NODE(&dso->rb_node))
-		pr_err("DSO %s is still in rbtree when being deleted!\n",
-		       dso->long_name);
+	if (dso->dsos)
+		pr_err("DSO %s is still in rbtree when being deleted!\n", dso->long_name);
 
 	/* free inlines first, as they reference symbols */
 	inlines__tree_delete(&dso->inlined_nodes);
diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
index 2c295438226d..b22dec8b3f3a 100644
--- a/tools/perf/util/dso.h
+++ b/tools/perf/util/dso.h
@@ -146,9 +146,7 @@ struct auxtrace_cache;
 
 struct dso {
 	struct mutex	 lock;
-	struct list_head node;
-	struct rb_node	 rb_node;	/* rbtree node sorted by long name */
-	struct rb_root	 *root;		/* root of rbtree that rb_node is in */
+	struct dsos	 *dsos;
 	struct rb_root_cached symbols;
 	struct symbol	 **symbol_names;
 	size_t		 symbol_names_len;
@@ -238,8 +236,8 @@ static inline void dso__set_loaded(struct dso *dso)
 	dso->loaded = true;
 }
 
-int dso_id__cmp(struct dso_id *a, struct dso_id *b);
-bool dso_id__empty(struct dso_id *id);
+int dso_id__cmp(const struct dso_id *a, const struct dso_id *b);
+bool dso_id__empty(const struct dso_id *id);
 
 struct dso *dso__new_id(const char *name, struct dso_id *id);
 struct dso *dso__new(const char *name);
@@ -248,7 +246,7 @@ void dso__delete(struct dso *dso);
 int dso__cmp_id(struct dso *a, struct dso *b);
 void dso__set_short_name(struct dso *dso, const char *name, bool name_allocated);
 void dso__set_long_name(struct dso *dso, const char *name, bool name_allocated);
-void dso__inject_id(struct dso *dso, struct dso_id *id);
+void __dso__inject_id(struct dso *dso, struct dso_id *id);
 
 int dso__name_len(const struct dso *dso);
 
diff --git a/tools/perf/util/dsos.c b/tools/perf/util/dsos.c
index b7fbfb877ae3..c01f0b538e65 100644
--- a/tools/perf/util/dsos.c
+++ b/tools/perf/util/dsos.c
@@ -14,24 +14,30 @@
 
 void dsos__init(struct dsos *dsos)
 {
-	INIT_LIST_HEAD(&dsos->head);
-	dsos->root = RB_ROOT;
 	init_rwsem(&dsos->lock);
+
+	dsos->cnt = 0;
+	dsos->allocated = 0;
+	dsos->dsos = NULL;
+	dsos->sorted = true;
 }
 
 static void dsos__purge(struct dsos *dsos)
 {
-	struct dso *pos, *n;
-
 	down_write(&dsos->lock);
 
-	list_for_each_entry_safe(pos, n, &dsos->head, node) {
-		RB_CLEAR_NODE(&pos->rb_node);
-		pos->root = NULL;
-		list_del_init(&pos->node);
-		dso__put(pos);
+	for (unsigned int i = 0; i < dsos->cnt; i++) {
+		struct dso *dso = dsos->dsos[i];
+
+		dso->dsos = NULL;
+		dso__put(dso);
 	}
 
+	zfree(&dsos->dsos);
+	dsos->cnt = 0;
+	dsos->allocated = 0;
+	dsos->sorted = true;
+
 	up_write(&dsos->lock);
 }
 
@@ -46,9 +52,8 @@ static int __dsos__for_each_dso(struct dsos *dsos,
 				int (*cb)(struct dso *dso, void *data),
 				void *data)
 {
-	struct dso *dso;
-
-	list_for_each_entry(dso, &dsos->head, node) {
+	for (unsigned int i = 0; i < dsos->cnt; i++) {
+		struct dso *dso = dsos->dsos[i];
 		int err;
 
 		err = cb(dso, data);
@@ -119,16 +124,47 @@ static int dso__cmp_short_name(struct dso *a, struct dso *b)
 	return __dso__cmp_short_name(a->short_name, &a->id, b);
 }
 
+static int dsos__cmp_long_name_id_short_name(const void *va, const void *vb)
+{
+	const struct dso *a = *((const struct dso **)va);
+	const struct dso *b = *((const struct dso **)vb);
+	int rc = strcmp(a->long_name, b->long_name);
+
+	if (!rc) {
+		rc = dso_id__cmp(&a->id, &b->id);
+		if (!rc)
+			rc = strcmp(a->short_name, b->short_name);
+	}
+	return rc;
+}
+
 /*
  * Find a matching entry and/or link current entry to RB tree.
  * Either one of the dso or name parameter must be non-NULL or the
  * function will not work.
  */
-struct dso *__dsos__findnew_link_by_longname_id(struct rb_root *root, struct dso *dso,
-						const char *name, struct dso_id *id)
+struct dso *__dsos__findnew_link_by_longname_id(struct dsos *dsos,
+						struct dso *dso,
+						const char *name,
+						struct dso_id *id,
+						bool write_locked)
 {
-	struct rb_node **p = &root->rb_node;
-	struct rb_node  *parent = NULL;
+	int low = 0, high = dsos->cnt - 1;
+
+	if (!dsos->sorted) {
+		if (!write_locked) {
+			up_read(&dsos->lock);
+			down_write(&dsos->lock);
+			dso = __dsos__findnew_link_by_longname_id(dsos, dso, name, id,
+								  /*write_locked=*/true);
+			up_write(&dsos->lock);
+			down_read(&dsos->lock);
+			return dso;
+		}
+		qsort(dsos->dsos, dsos->cnt, sizeof(struct dso *),
+		      dsos__cmp_long_name_id_short_name);
+		dsos->sorted = true;
+	}
 
 	if (!name)
 		name = dso->long_name;
@@ -136,11 +172,11 @@ struct dso *__dsos__findnew_link_by_longname_id(struct rb_root *root, struct dso
 	/*
 	 * Find node with the matching name
 	 */
-	while (*p) {
-		struct dso *this = rb_entry(*p, struct dso, rb_node);
+	while (low <= high) {
+		int mid = (low + high) / 2;
+		struct dso *this = dsos->dsos[mid];
 		int rc = __dso__cmp_long_name(name, id, this);
 
-		parent = *p;
 		if (rc == 0) {
 			/*
 			 * In case the new DSO is a duplicate of an existing
@@ -161,56 +197,53 @@ struct dso *__dsos__findnew_link_by_longname_id(struct rb_root *root, struct dso
 			}
 		}
 		if (rc < 0)
-			p = &parent->rb_left;
+			high = mid - 1;
 		else
-			p = &parent->rb_right;
-	}
-	if (dso) {
-		/* Add new node and rebalance tree */
-		rb_link_node(&dso->rb_node, parent, p);
-		rb_insert_color(&dso->rb_node, root);
-		dso->root = root;
+			low = mid + 1;
 	}
+	if (dso)
+		__dsos__add(dsos, dso);
 	return NULL;
 }
 
-void __dsos__add(struct dsos *dsos, struct dso *dso)
+int __dsos__add(struct dsos *dsos, struct dso *dso)
 {
-	list_add_tail(&dso->node, &dsos->head);
-	__dsos__findnew_link_by_longname_id(&dsos->root, dso, NULL, &dso->id);
-	/*
-	 * It is now in the linked list, grab a reference, then garbage collect
-	 * this when needing memory, by looking at LRU dso instances in the
-	 * list with atomic_read(&dso->refcnt) == 1, i.e. no references
-	 * anywhere besides the one for the list, do, under a lock for the
-	 * list: remove it from the list, then a dso__put(), that probably will
-	 * be the last and will then call dso__delete(), end of life.
-	 *
-	 * That, or at the end of the 'struct machine' lifetime, when all
-	 * 'struct dso' instances will be removed from the list, in
-	 * dsos__exit(), if they have no other reference from some other data
-	 * structure.
-	 *
-	 * E.g.: after processing a 'perf.data' file and storing references
-	 * to objects instantiated while processing events, we will have
-	 * references to the 'thread', 'map', 'dso' structs all from 'struct
-	 * hist_entry' instances, but we may not need anything not referenced,
-	 * so we might as well call machines__exit()/machines__delete() and
-	 * garbage collect it.
-	 */
-	dso__get(dso);
+	if (dsos->cnt == dsos->allocated) {
+		unsigned int to_allocate = 2;
+		struct dso **temp;
+
+		if (dsos->allocated > 0)
+			to_allocate = dsos->allocated * 2;
+		temp = realloc(dsos->dsos, sizeof(struct dso *) * to_allocate);
+		if (!temp)
+			return -ENOMEM;
+		dsos->dsos = temp;
+		dsos->allocated = to_allocate;
+	}
+	dsos->dsos[dsos->cnt++] = dso__get(dso);
+	if (dsos->cnt >= 2 && dsos->sorted) {
+		dsos->sorted = dsos__cmp_long_name_id_short_name(&dsos->dsos[dsos->cnt - 2],
+								 &dsos->dsos[dsos->cnt - 1])
+			<= 0;
+	}
+	dso->dsos = dsos;
+	return 0;
 }
 
-void dsos__add(struct dsos *dsos, struct dso *dso)
+int dsos__add(struct dsos *dsos, struct dso *dso)
 {
+	int ret;
+
 	down_write(&dsos->lock);
-	__dsos__add(dsos, dso);
+	ret = __dsos__add(dsos, dso);
 	up_write(&dsos->lock);
+	return ret;
 }
 
-static struct dso *__dsos__findnew_by_longname_id(struct rb_root *root, const char *name, struct dso_id *id)
+static struct dso *__dsos__findnew_by_longname_id(struct dsos *dsos, const char *name,
+						struct dso_id *id, bool write_locked)
 {
-	return __dsos__findnew_link_by_longname_id(root, NULL, name, id);
+	return __dsos__findnew_link_by_longname_id(dsos, NULL, name, id, write_locked);
 }
 
 struct dsos__find_id_cb_args {
@@ -231,7 +264,8 @@ static int dsos__find_id_cb(struct dso *dso, void *data)
 
 }
 
-static struct dso *__dsos__find_id(struct dsos *dsos, const char *name, struct dso_id *id, bool cmp_short)
+static struct dso *__dsos__find_id(struct dsos *dsos, const char *name, struct dso_id *id,
+				   bool cmp_short, bool write_locked)
 {
 	struct dso *res;
 
@@ -245,7 +279,7 @@ static struct dso *__dsos__find_id(struct dsos *dsos, const char *name, struct d
 		__dsos__for_each_dso(dsos, dsos__find_id_cb, &args);
 		return args.res;
 	}
-	res = __dsos__findnew_by_longname_id(&dsos->root, name, id);
+	res = __dsos__findnew_by_longname_id(dsos, name, id, write_locked);
 	return res;
 }
 
@@ -254,7 +288,7 @@ struct dso *dsos__find(struct dsos *dsos, const char *name, bool cmp_short)
 	struct dso *res;
 
 	down_read(&dsos->lock);
-	res = __dsos__find_id(dsos, name, NULL, cmp_short);
+	res = __dsos__find_id(dsos, name, NULL, cmp_short, /*write_locked=*/false);
 	up_read(&dsos->lock);
 	return res;
 }
@@ -296,8 +330,13 @@ static struct dso *__dsos__addnew_id(struct dsos *dsos, const char *name, struct
 	struct dso *dso = dso__new_id(name, id);
 
 	if (dso != NULL) {
-		__dsos__add(dsos, dso);
+		/*
+		 * The dsos lock is held on entry, so rename the dso before
+		 * adding it to avoid needing to take the dsos lock again to say
+		 * the array isn't sorted.
+		 */
 		dso__set_basename(dso);
+		__dsos__add(dsos, dso);
 	}
 	return dso;
 }
@@ -309,10 +348,10 @@ struct dso *__dsos__addnew(struct dsos *dsos, const char *name)
 
 static struct dso *__dsos__findnew_id(struct dsos *dsos, const char *name, struct dso_id *id)
 {
-	struct dso *dso = __dsos__find_id(dsos, name, id, false);
+	struct dso *dso = __dsos__find_id(dsos, name, id, false, /*write_locked=*/true);
 
 	if (dso && dso_id__empty(&dso->id) && !dso_id__empty(id))
-		dso__inject_id(dso, id);
+		__dso__inject_id(dso, id);
 
 	return dso ? dso : __dsos__addnew_id(dsos, name, id);
 }
@@ -403,18 +442,27 @@ struct dso *dsos__findnew_module_dso(struct dsos *dsos,
 
 	down_write(&dsos->lock);
 
-	dso = __dsos__find_id(dsos, m->name, NULL, /*cmp_short=*/true);
-	if (!dso) {
-		dso = __dsos__addnew(dsos, m->name);
-		if (dso == NULL)
-			goto out_unlock;
-
-		dso__set_module_info(dso, m, machine);
-		dso__set_long_name(dso, strdup(filename), true);
-		dso->kernel = DSO_SPACE__KERNEL;
+	dso = __dsos__find_id(dsos, m->name, NULL, /*cmp_short=*/true, /*write_locked=*/true);
+	if (dso) {
+		up_write(&dsos->lock);
+		return dso;
 	}
+	/*
+	 * Failed to find the dso so create it. Change the name before adding it
+	 * to the array, to avoid unnecessary sorts and potential locking
+	 * issues.
+	 */
+	dso = dso__new_id(m->name, /*id=*/NULL);
+	if (!dso) {
+		up_write(&dsos->lock);
+		return NULL;
+	}
+	dso__set_basename(dso);
+	dso__set_module_info(dso, m, machine);
+	dso__set_long_name(dso,	strdup(filename), true);
+	dso->kernel = DSO_SPACE__KERNEL;
+	__dsos__add(dsos, dso);
 
-out_unlock:
 	up_write(&dsos->lock);
 	return dso;
 }
diff --git a/tools/perf/util/dsos.h b/tools/perf/util/dsos.h
index 50bd51523475..c1b3979ad4bd 100644
--- a/tools/perf/util/dsos.h
+++ b/tools/perf/util/dsos.h
@@ -14,20 +14,22 @@ struct kmod_path;
 struct machine;
 
 /*
- * DSOs are put into both a list for fast iteration and rbtree for fast
- * long name lookup.
+ * Collection of DSOs as an array for iteration speed, but sorted for O(n)
+ * lookup.
  */
 struct dsos {
-	struct list_head    head;
-	struct rb_root	    root;	/* rbtree root sorted by long name */
 	struct rw_semaphore lock;
+	struct dso **dsos;
+	unsigned int cnt;
+	unsigned int allocated;
+	bool sorted;
 };
 
 void dsos__init(struct dsos *dsos);
 void dsos__exit(struct dsos *dsos);
 
-void __dsos__add(struct dsos *dsos, struct dso *dso);
-void dsos__add(struct dsos *dsos, struct dso *dso);
+int __dsos__add(struct dsos *dsos, struct dso *dso);
+int dsos__add(struct dsos *dsos, struct dso *dso);
 struct dso *__dsos__addnew(struct dsos *dsos, const char *name);
 struct dso *dsos__find(struct dsos *dsos, const char *name, bool cmp_short);
 
@@ -35,8 +37,11 @@ struct dso *dsos__findnew_id(struct dsos *dsos, const char *name, struct dso_id
  
 bool dsos__read_build_ids(struct dsos *dsos, bool with_hits);
 
-struct dso *__dsos__findnew_link_by_longname_id(struct rb_root *root, struct dso *dso,
-						const char *name, struct dso_id *id);
+struct dso *__dsos__findnew_link_by_longname_id(struct dsos *dsos,
+						struct dso *dso,
+						const char *name,
+						struct dso_id *id,
+						bool write_locked);
 
 size_t dsos__fprintf_buildid(struct dsos *dsos, FILE *fp,
 			       bool (skip)(struct dso *dso, int parm), int parm);