name : draw_functrace.py #!/usr/bin/env python # SPDX-License-Identifier: GPL-2.0-only """ Copyright 2008 (c) Frederic Weisbecker <fweisbec@gmail.com> 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 call time are provided. Usage: Be sure that you have CONFIG_FUNCTION_TRACER # mount -t tracefs nodev /sys/kernel/tracing # echo function > /sys/kernel/tracing/current_tracer $ cat /sys/kernel/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/tracing/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("[^]]+?\\] +([a-z.]+) +([0-9.]+): (\\w+) <-(\\w+)", line) if m is None: raise BrokenLineException return (m.group(2), m.group(3), m.group(4)) 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()