4 files changed, 196 insertions, 25 deletions

diff --git a/tools/perf/util/comm.c b/tools/perf/util/comm.c
new file mode 100644
index 000000000000..8b3ac9f0207f
--- /dev/null
+++ b/tools/perf/util/comm.c
@@ -0,0 +1,106 @@
+#include "comm.h"
+#include "util.h"
+#include <stdlib.h>
+#include <stdio.h>
+
+struct comm_str {
+	char *str;
+	struct rb_node rb_node;
+	int ref;
+};
+
+/* Should perhaps be moved to struct machine */
+static struct rb_root comm_str_root;
+
+static void comm_str__get(struct comm_str *cs)
+{
+	cs->ref++;
+}
+
+static void comm_str__put(struct comm_str *cs)
+{
+	if (!--cs->ref) {
+		rb_erase(&cs->rb_node, &comm_str_root);
+		free(cs->str);
+		free(cs);
+	}
+}
+
+static struct comm_str *comm_str__alloc(const char *str)
+{
+	struct comm_str *cs;
+
+	cs = zalloc(sizeof(*cs));
+	if (!cs)
+		return NULL;
+
+	cs->str = strdup(str);
+	if (!cs->str) {
+		free(cs);
+		return NULL;
+	}
+
+	return cs;
+}
+
+static struct comm_str *comm_str__findnew(const char *str, struct rb_root *root)
+{
+	struct rb_node **p = &root->rb_node;
+	struct rb_node *parent = NULL;
+	struct comm_str *iter, *new;
+	int cmp;
+
+	while (*p != NULL) {
+		parent = *p;
+		iter = rb_entry(parent, struct comm_str, rb_node);
+
+		cmp = strcmp(str, iter->str);
+		if (!cmp)
+			return iter;
+
+		if (cmp < 0)
+			p = &(*p)->rb_left;
+		else
+			p = &(*p)->rb_right;
+	}
+
+	new = comm_str__alloc(str);
+	if (!new)
+		return NULL;
+
+	rb_link_node(&new->rb_node, parent, p);
+	rb_insert_color(&new->rb_node, root);
+
+	return new;
+}
+
+struct comm *comm__new(const char *str, u64 timestamp)
+{
+	struct comm *comm = zalloc(sizeof(*comm));
+
+	if (!comm)
+		return NULL;
+
+	comm->start = timestamp;
+
+	comm->comm_str = comm_str__findnew(str, &comm_str_root);
+	if (!comm->comm_str) {
+		free(comm);
+		return NULL;
+	}
+
+	comm_str__get(comm->comm_str);
+
+	return comm;
+}
+
+void comm__free(struct comm *comm)
+{
+	comm_str__put(comm->comm_str);
+	free(comm);
+}
+
+const char *comm__str(const struct comm *comm)
+{
+	return comm->comm_str->str;
+}
diff --git a/tools/perf/util/comm.h b/tools/perf/util/comm.h
new file mode 100644
index 000000000000..f62d215bede2
--- /dev/null
+++ b/tools/perf/util/comm.h
@@ -0,0 +1,20 @@
+#ifndef __PERF_COMM_H
+#define __PERF_COMM_H
+
+#include "../perf.h"
+#include <linux/rbtree.h>
+#include <linux/list.h>
+
+struct comm_str;
+
+struct comm {
+	struct comm_str *comm_str;
+	u64 start;
+	struct list_head list;
+};
+
+void comm__free(struct comm *comm);
+struct comm *comm__new(const char *str, u64 timestamp);
+const char *comm__str(const struct comm *comm);
+
+#endif  /* __PERF_COMM_H */
diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index 0ea73fe383f5..15c53c2e109e 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -6,9 +6,12 @@
 #include "thread.h"
 #include "util.h"
 #include "debug.h"
+#include "comm.h"
 
 struct thread *thread__new(pid_t pid, pid_t tid)
 {
+	char *comm_str;
+	struct comm *comm;
 	struct thread *thread = zalloc(sizeof(*thread));
 
 	if (thread != NULL) {
@@ -16,47 +19,88 @@ struct thread *thread__new(pid_t pid, pid_t tid)
 		thread->pid_ = pid;
 		thread->tid = tid;
 		thread->ppid = -1;
-		thread->comm = malloc(32);
-		if (thread->comm)
-			snprintf(thread->comm, 32, ":%d", thread->tid);
+		INIT_LIST_HEAD(&thread->comm_list);
+
+		comm_str = malloc(32);
+		if (!comm_str)
+			goto err_thread;
+
+		snprintf(comm_str, 32, ":%d", tid);
+		comm = comm__new(comm_str, 0);
+		free(comm_str);
+		if (!comm)
+			goto err_thread;
+
+		list_add(&comm->list, &thread->comm_list);
 	}
 
 	return thread;
+
+err_thread:
+	free(thread);
+	return NULL;
 }
 
 void thread__delete(struct thread *thread)
 {
+	struct comm *comm, *tmp;
+
 	map_groups__exit(&thread->mg);
-	free(thread->comm);
+	list_for_each_entry_safe(comm, tmp, &thread->comm_list, list) {
+		list_del(&comm->list);
+		comm__free(comm);
+	}
+
 	free(thread);
 }
 
-int thread__set_comm(struct thread *thread, const char *comm,
-		     u64 timestamp __maybe_unused)
+static struct comm *thread__comm(const struct thread *thread)
 {
-	int err;
+	if (list_empty(&thread->comm_list))
+		return NULL;
 
-	if (thread->comm)
-		free(thread->comm);
-	thread->comm = strdup(comm);
-	err = thread->comm == NULL ? -ENOMEM : 0;
-	if (!err) {
-		thread->comm_set = true;
+	return list_first_entry(&thread->comm_list, struct comm, list);
+}
+
+/* CHECKME: time should always be 0 if event aren't ordered */
+int thread__set_comm(struct thread *thread, const char *str, u64 timestamp)
+{
+	struct comm *new, *curr = thread__comm(thread);
+
+	/* Override latest entry if it had no specific time coverage */
+	if (!curr->start) {
+		list_del(&curr->list);
+		comm__free(curr);
 	}
-	return err;
+
+	new = comm__new(str, timestamp);
+	if (!new)
+		return -ENOMEM;
+
+	list_add(&new->list, &thread->comm_list);
+	thread->comm_set = true;
+
+	return 0;
 }
 
 const char *thread__comm_str(const struct thread *thread)
 {
-	return thread->comm;
+	const struct comm *comm = thread__comm(thread);
+
+	if (!comm)
+		return NULL;
+
+	return comm__str(comm);
 }
 
+/* CHECKME: it should probably better return the max comm len from its comm list */
 int thread__comm_len(struct thread *thread)
 {
 	if (!thread->comm_len) {
-		if (!thread->comm)
+		const char *comm = thread__comm_str(thread);
+		if (!comm)
 			return 0;
-		thread->comm_len = strlen(thread->comm);
+		thread->comm_len = strlen(comm);
 	}
 
 	return thread->comm_len;
@@ -74,17 +118,17 @@ void thread__insert_map(struct thread *thread, struct map *map)
 	map_groups__insert(&thread->mg, map);
 }
 
-int thread__fork(struct thread *thread, struct thread *parent,
-		 u64 timestamp __maybe_unused)
+int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp)
 {
-	int i;
+	int i, err;
 
 	if (parent->comm_set) {
-		if (thread->comm)
-			free(thread->comm);
-		thread->comm = strdup(parent->comm);
-		if (!thread->comm)
+		const char *comm = thread__comm_str(parent);
+		if (!comm)
 			return -ENOMEM;
+		err = thread__set_comm(thread, comm, timestamp);
+		if (!err)
+			return err;
 		thread->comm_set = true;
 	}
 
diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h
index 4e9724270a64..8702c6b4163a 100644
--- a/tools/perf/util/thread.h
+++ b/tools/perf/util/thread.h
@@ -2,6 +2,7 @@
 #define __PERF_THREAD_H
 
 #include <linux/rbtree.h>
+#include <linux/list.h>
 #include <unistd.h>
 #include <sys/types.h>
 #include "symbol.h"
@@ -18,7 +19,7 @@ struct thread {
 	char			shortname[3];
 	bool			comm_set;
 	bool			dead; /* if set thread has exited */
-	char			*comm;
+	struct list_head	comm_list;
 	int			comm_len;
 
 	void			*priv;