#!/usr/bin/python
"""
Copyright 2008 (c) Frederic Weisbecker <fweisbec@gmail.com>
Licensed under the terms of the GNU GPL License version 2
This script parses a trace provided by the function tracer in
kernel/trace/trace_functions.c
The resulted trace is processed into a tree to produce a more human
view of the call stack by drawing textual but hierarchical tree of
calls. Only the functions's names and the the call time are provided.
Usage:
Be sure that you have CONFIG_FUNCTION_TRACER
# mount -t debugfs nodev /sys/kernel/debug
# echo function > /sys/kernel/debug/tracing/current_tracer
$ cat /sys/kernel/debug/tracing/trace_pipe > ~/raw_trace_func
Wait some times but not too much, the script is a bit slow.
Break the pipe (Ctrl + Z)
$ scripts/draw_functrace.py < raw_trace_func > draw_functrace
Then you have your drawn trace in draw_functrace
"""
import sys, re
class CallTree:
""" This class provides a tree representation of the functions
call stack. If a function has no parent in the kernel (interrupt,
syscall, kernel thread...) then it is attached to a virtual parent
called ROOT.
"""
ROOT = None
def __init__(self, func, time = None, parent = None):
self._func = func
self._time = time
if parent is None:
self._parent = CallTree.ROOT
else:
self._parent = parent
self._children = []
def calls(self, func, calltime):
""" If a function calls another one, call this method to insert it
into the tree at the appropriate place.
@return: A reference to the newly created child node.
"""
child = CallTree(func, calltime, self)
self._children.append(child)
return child
def getParent(self, func):
""" Retrieve the last parent of the current node that
has the name given by func. If this function is not
on a parent, then create it as new child of root
@return: A reference to the parent.
"""
tree = self
while tree != CallTree.ROOT and tree._func != func:
tree = tree._parent
if tree == CallTree.ROOT:
child = CallTree.ROOT.calls(func, None)
return child
return tree
def __repr__(self):
return self.__toString("", True)
def __toString(self, branch, lastChild):
if self._time is not None:
s = "%s----%s (%s)\n" % (branch, self._func, self._time)
else:
s = "%s----%s\n" % (branch, self._func)
i = 0
if lastChild:
branch = branch[:-1] + " "
while i < len(self._children):
if i != len(self._children) - 1:
s += "%s" % self._children[i].__toString(branch +\
" |", False)
else:
s += "%s" % self._children[i].__toString(branch +\
" |", True)
i += 1
return s
class BrokenLineException(Exception):
"""If the last line is not complete because of the pipe breakage,
we want to stop the processing and ignore this line.
"""
pass
class CommentLineException(Exception):
""" If the line is a comment (as in the beginning of the trace file),
just ignore it.
"""
pass
def parseLine(line):
line = line.strip()
if line.startswith("#"):
raise CommentLineException
m = re.match("[^]]+?\\] +([0-9.]+): (\\w+) <-(\\w+)", line)
if m is None:
raise BrokenLineException
return (m.group(1), m.group(2), m.group(3))
def main():
CallTree.ROOT = CallTree("Root (Nowhere)", None, None)
tree = CallTree.ROOT
for line in sys.stdin:
try:
calltime, callee, caller = parseLine(line)
except BrokenLineException:
break
except CommentLineException:
continue
tree = tree.getParent(caller)
tree = tree.calls(callee, calltime)
print(CallTree.ROOT)
if __name__ == "__main__":
main()
