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Subject[PATCH 15/38] perf tools: Convert dead thread list into rbtree
Date
Currently perf maintains dead threads in a linked list but this can be
a problem if someone needs to search from it especially in a large
session which might have many dead threads. Convert it to a rbtree
like normal threads and it'll be used later with multi-file changes.

The list node is now used for chaining dead threads of same tid since
it's easier to handle such threads in time order.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
tools/perf/util/machine.c | 70 +++++++++++++++++++++++++++++++++++++++++------
tools/perf/util/machine.h | 2 +-
tools/perf/util/thread.c | 1 +
tools/perf/util/thread.h | 11 ++++----
4 files changed, 68 insertions(+), 16 deletions(-)

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 9e0f60a7e7b3..6b8236dc4367 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -28,7 +28,7 @@ int machine__init(struct machine *machine, const char *root_dir, pid_t pid)
dsos__init(&machine->kernel_dsos);

machine->threads = RB_ROOT;
- INIT_LIST_HEAD(&machine->dead_threads);
+ machine->dead_threads = RB_ROOT;
machine->last_match = NULL;

machine->vdso_info = NULL;
@@ -91,10 +91,22 @@ static void dsos__delete(struct dsos *dsos)

void machine__delete_dead_threads(struct machine *machine)
{
- struct thread *n, *t;
+ struct rb_node *nd = rb_first(&machine->dead_threads);
+
+ while (nd) {
+ struct thread *t = rb_entry(nd, struct thread, rb_node);
+ struct thread *pos;
+
+ nd = rb_next(nd);
+ rb_erase(&t->rb_node, &machine->dead_threads);
+
+ while (!list_empty(&t->tid_node)) {
+ pos = list_first_entry(&t->tid_node,
+ struct thread, tid_node);
+ list_del(&pos->tid_node);
+ thread__delete(pos);
+ }

- list_for_each_entry_safe(t, n, &machine->dead_threads, node) {
- list_del(&t->node);
thread__delete(t);
}
}
@@ -106,8 +118,8 @@ void machine__delete_threads(struct machine *machine)
while (nd) {
struct thread *t = rb_entry(nd, struct thread, rb_node);

- rb_erase(&t->rb_node, &machine->threads);
nd = rb_next(nd);
+ rb_erase(&t->rb_node, &machine->threads);
thread__delete(t);
}
}
@@ -1238,13 +1250,46 @@ int machine__process_mmap_event(struct machine *machine, union perf_event *event

static void machine__remove_thread(struct machine *machine, struct thread *th)
{
+ struct rb_node **p = &machine->dead_threads.rb_node;
+ struct rb_node *parent = NULL;
+ struct thread *pos;
+
machine->last_match = NULL;
rb_erase(&th->rb_node, &machine->threads);
+
+ th->dead = true;
+
/*
* We may have references to this thread, for instance in some hist_entry
- * instances, so just move them to a separate list.
+ * instances, so just move them to a separate list in rbtree.
*/
- list_add_tail(&th->node, &machine->dead_threads);
+ while (*p != NULL) {
+ parent = *p;
+ pos = rb_entry(parent, struct thread, rb_node);
+
+ if (pos->tid == th->tid) {
+ struct thread *old;
+
+ /* sort by time */
+ list_for_each_entry(old, &pos->tid_node, tid_node) {
+ if (th->start_time >= old->start_time) {
+ pos = old;
+ break;
+ }
+ }
+
+ list_add_tail(&th->tid_node, &pos->tid_node);
+ return;
+ }
+
+ if (th->tid < pos->tid)
+ p = &(*p)->rb_left;
+ else
+ p = &(*p)->rb_right;
+ }
+
+ rb_link_node(&th->rb_node, parent, p);
+ rb_insert_color(&th->rb_node, &machine->dead_threads);
}

int machine__process_fork_event(struct machine *machine, union perf_event *event,
@@ -1729,7 +1774,7 @@ int machine__for_each_thread(struct machine *machine,
void *priv)
{
struct rb_node *nd;
- struct thread *thread;
+ struct thread *thread, *pos;
int rc = 0;

for (nd = rb_first(&machine->threads); nd; nd = rb_next(nd)) {
@@ -1739,10 +1784,17 @@ int machine__for_each_thread(struct machine *machine,
return rc;
}

- list_for_each_entry(thread, &machine->dead_threads, node) {
+ for (nd = rb_first(&machine->dead_threads); nd; nd = rb_next(nd)) {
+ thread = rb_entry(nd, struct thread, rb_node);
rc = fn(thread, priv);
if (rc != 0)
return rc;
+
+ list_for_each_entry(pos, &thread->tid_node, tid_node) {
+ rc = fn(pos, priv);
+ if (rc != 0)
+ return rc;
+ }
}
return rc;
}
diff --git a/tools/perf/util/machine.h b/tools/perf/util/machine.h
index e8b7779a0a3f..4349946a38ff 100644
--- a/tools/perf/util/machine.h
+++ b/tools/perf/util/machine.h
@@ -30,7 +30,7 @@ struct machine {
bool comm_exec;
char *root_dir;
struct rb_root threads;
- struct list_head dead_threads;
+ struct rb_root dead_threads;
struct thread *last_match;
struct vdso_info *vdso_info;
struct dsos user_dsos;
diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index ad96725105c2..c9ae0e1599da 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -38,6 +38,7 @@ struct thread *thread__new(pid_t pid, pid_t tid)
thread->ppid = -1;
thread->cpu = -1;
INIT_LIST_HEAD(&thread->comm_list);
+ INIT_LIST_HEAD(&thread->tid_node);

if (unwind__prepare_access(thread) < 0)
goto err_thread;
diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h
index be67c3bad5e7..21268e66b2ad 100644
--- a/tools/perf/util/thread.h
+++ b/tools/perf/util/thread.h
@@ -11,10 +11,8 @@
struct thread_stack;

struct thread {
- union {
- struct rb_node rb_node;
- struct list_head node;
- };
+ struct rb_node rb_node;
+ struct list_head tid_node;
struct map_groups *mg;
pid_t pid_; /* Not all tools update this */
pid_t tid;
@@ -22,7 +20,8 @@ struct thread {
int cpu;
char shortname[3];
bool comm_set;
- bool dead; /* if set thread has exited */
+ bool exited; /* if set thread has exited */
+ bool dead; /* thread is in dead_threads list */
struct list_head comm_list;
int comm_len;
u64 db_id;
@@ -39,7 +38,7 @@ int thread__init_map_groups(struct thread *thread, struct machine *machine);
void thread__delete(struct thread *thread);
static inline void thread__exited(struct thread *thread)
{
- thread->dead = true;
+ thread->exited = true;
}

int __thread__set_comm(struct thread *thread, const char *comm, u64 timestamp,
--
2.2.2


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