[PATCH 6/6] scripts/timers: Add timer_migration_tree.py

From: Frederic Weisbecker

Date: Thu Apr 23 2026 - 12:55:27 EST


Introduce a script that provides a simple ascii representation of the
timer migration tree on top of boot trace events.

First boot with:

trace_event==tmigr_connect_cpu_parent,tmigr_connect_child_parent

Then parse the result with:

scripts/timer_migration_tree.py < /sys/kernel/tracing/trace

On a system with 8 CPUs, this produces the following output:

Tree for capacity 1024

/-0, node 0, lvl:-1
|
|--1, node 0, lvl:-1
|
|--2, node 0, lvl:-1
|
|--3, node 0, lvl:-1
-- /00000000dcebac8b, node 0, lvl:0
|--4, node 0, lvl:-1
|
|--5, node 0, lvl:-1
|
|--6, node 0, lvl:-1
|
\-7, node 0, lvl:-1

Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
---
scripts/timer_migration_tree.py | 122 ++++++++++++++++++++++++++++++++
1 file changed, 122 insertions(+)
create mode 100755 scripts/timer_migration_tree.py

diff --git a/scripts/timer_migration_tree.py b/scripts/timer_migration_tree.py
new file mode 100755
index 000000000000..faac9de854bd
--- /dev/null
+++ b/scripts/timer_migration_tree.py
@@ -0,0 +1,122 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+
+"""
+Draw the timer migration tree.
+
+1) Boot with trace_event==tmigr_connect_cpu_parent,tmigr_connect_child_parent
+2) ./timer_migration_tree.py < /sys/kernel/tracing/trace
+"""
+
+import re, sys
+from ete3 import Tree
+
+class Node:
+ def __init__(self, group):
+ self.group = group
+ self.children = []
+ self.parent = None
+ self.num_children = 0
+ self.groupmask = 0
+ self.lvl = -1
+
+ def set_groupmask(self, groupmask):
+ self.groupmask = groupmask
+
+ def set_parent(self, parent):
+ self.parent = parent
+
+ def add_child(self, child):
+ self.children.append(child)
+
+ def set_lvl(self, lvl):
+ self.lvl = lvl
+
+ def set_numa(self, numa):
+ self.numa = numa
+
+ def set_num_children(self, num_children):
+ self.num_children = num_children
+
+ def __repr__(self):
+ if self.parent:
+ parent_grp = self.parent.group
+ else:
+ parent_grp = "-"
+ return "Group: %s mask: %s parent: %s lvl: %d numa: %d num_children: %d" % (self.group, self.groupmask, parent_grp, self.lvl, self.numa, self.num_children)
+
+hierarchies = { }
+
+def get_hierarchy(capacity):
+ if capacity not in hierarchies:
+ hierarchies[capacity] = {}
+ return hierarchies[capacity]
+
+def get_node(capacity, group):
+ hier = get_hierarchy(capacity)
+ if group in hier:
+ return hier[group]
+ else:
+ n = Node(group)
+ hier[group] = n
+ return n
+
+def tmigr_connect_cpu_parent(ts, line):
+ s = re.search("tmigr_connect_cpu_parent: cpu=([0-9]+) groupmask=([0-9a-zA-Z]+) parent=([0-9a-zA-Z]+) lvl=([0-9]+) numa=([-]?[0-9]+) capacity=([-]?[0-9]+) num_children=([0-9]+)", line)
+ if s is None:
+ return False
+ (cpu, groupmask, parent, lvl, numa, capacity, num_children) = (int(s.group(1)), s.group(2), s.group(3), int(s.group(4)), int(s.group(5)), int(s.group(6)), int(s.group(7)))
+ n = get_node(capacity, cpu)
+ p = get_node(capacity, parent)
+ n.set_parent(p)
+ n.set_groupmask(groupmask)
+ n.set_lvl(-1)
+ p.set_lvl(lvl)
+ p.set_numa(numa)
+ n.set_numa(numa)
+ p.set_num_children(num_children)
+ p.add_child(n)
+
+def tmigr_connect_child_parent(ts, line):
+ s = re.search("tmigr_connect_child_parent: group=([0-9a-zA-Z]+) groupmask=([0-9a-zA-Z]+) parent=([0-9a-zA-Z]+) lvl=([0-9]+) numa=([-]?[0-9]+) capacity=([-]?[0-9]+) num_children=([0-9]+)", line)
+ if s is None:
+ return False
+ (group, groupmask, parent, lvl, numa, capacity, num_children) = (s.group(1), s.group(2), s.group(3), int(s.group(4)), int(s.group(5)), int(s.group(6)), int(s.group(7)))
+ n = get_node(capacity, group)
+ p = get_node(capacity, parent)
+ n.set_parent(p)
+ n.set_groupmask(groupmask)
+ p.set_lvl(lvl)
+ p.set_numa(numa)
+ p.set_num_children(num_children)
+ p.add_child(n)
+
+def populate(enode, node):
+ enode = enode.add_child(name = node.group)
+ enode.add_feature("groupmask", "m:%s" % node.groupmask)
+ enode.add_feature("lvl", "lvl:%d" % node.lvl)
+ enode.add_feature("numa", "node %d" % node.numa)
+ enode.add_feature("num_children", "c=%d" % node.num_children)
+ for child in node.children:
+ populate(enode, child)
+
+if __name__ == "__main__":
+ for line in sys.stdin:
+ s = re.search("([0-9]+[.][0-9]{6}): (.+?)$", line, re.S)
+ if s is not None:
+ if tmigr_connect_cpu_parent(float(s.group(1)), s.group(2)):
+ continue
+ if tmigr_connect_child_parent(float(s.group(1)), s.group(2)):
+ continue
+
+ for cap in hierarchies:
+ h = hierarchies[cap]
+ print("Tree for capacity %d" % cap)
+ for k in h:
+ n = h[k]
+ while n.parent != None:
+ n = n.parent
+ root = Tree()
+ populate(root, n)
+ print(root.get_ascii(show_internal=True, attributes=["name", "numa", "lvl"]))
+ break
--
2.53.0