perf script: Add stackcollapse.py script

Add stackcollapse.py script as an example of parsing call chains, and
also of using optparse to access command line options.

The flame graph tools include a set of scripts that parse output from
various tools (including "perf script"), remove the offsets in the
function and collapse each stack to a single line. The website also
says "perf report could have a report style [...] that output folded
stacks directly, obviating the need for stackcollapse-perf.pl", so here
it is.

This script is a Python rewrite of stackcollapse-perf.pl, using the perf
scripting interface to access the perf data directly from Python.

Signed-off-by: Paolo Bonzini <[e-mail]>
Acked-by: Jiri Olsa <[e-mail]>
Cc: Brendan Gregg <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/scripts/python/bin/stackcollapse-record

···
+#!/bin/sh
+
+#
+# stackcollapse.py can cover all type of perf samples including
+# the tracepoints, so no special record requirements, just record what
+# you want to analyze.
+#
+perf record "$@"

tools/perf/scripts/python/bin/stackcollapse-report

···
+#!/bin/sh
+# description: produce callgraphs in short form for scripting use
+perf script -s "$PERF_EXEC_PATH"/scripts/python/stackcollapse.py -- "$@"

tools/perf/scripts/python/stackcollapse.py

···
+#!/usr/bin/perl -w
+#
+# stackcollapse.py - format perf samples with one line per distinct call stack
+#
+# This script's output has two space-separated fields.  The first is a semicolon
+# separated stack including the program name (from the "comm" field) and the
+# function names from the call stack.  The second is a count:
+#
+#  swapper;start_kernel;rest_init;cpu_idle;default_idle;native_safe_halt 2
+#
+# The file is sorted according to the first field.
+#
+# Input may be created and processed using:
+#
+#  perf record -a -g -F 99 sleep 60
+#  perf script report stackcollapse > out.stacks-folded
+#
+# (perf script record stackcollapse works too).
+#
+# Written by Paolo Bonzini <[e-mail]>
+# Based on Brendan Gregg's stackcollapse-perf.pl script.
+
+import os
+import sys
+from collections import defaultdict
+from optparse import OptionParser, make_option
+
+sys.path.append(os.environ['PERF_EXEC_PATH'] + \
+                '/scripts/python/Perf-Trace-Util/lib/Perf/Trace')
+
+from perf_trace_context import *
+from Core import *
+from EventClass import *
+
+# command line parsing
+
+option_list = [
+    # formatting options for the bottom entry of the stack
+    make_option("--include-tid", dest="include_tid",
+                 action="store_true", default=False,
+                 help="include thread id in stack"),
+    make_option("--include-pid", dest="include_pid",
+                 action="store_true", default=False,
+                 help="include process id in stack"),
+    make_option("--no-comm", dest="include_comm",
+                 action="store_false", default=True,
+                 help="do not separate stacks according to comm"),
+    make_option("--tidy-java", dest="tidy_java",
+                 action="store_true", default=False,
+                 help="beautify Java signatures"),
+    make_option("--kernel", dest="annotate_kernel",
+                 action="store_true", default=False,
+                 help="annotate kernel functions with _[k]")
+]
+
+parser = OptionParser(option_list=option_list)
+(opts, args) = parser.parse_args()
+
+if len(args) != 0:
+    parser.error("unexpected command line argument")
+if opts.include_tid and not opts.include_comm:
+    parser.error("requesting tid but not comm is invalid")
+if opts.include_pid and not opts.include_comm:
+    parser.error("requesting pid but not comm is invalid")
+
+# event handlers
+
+lines = defaultdict(lambda: 0)
+
+def process_event(param_dict):
+    def tidy_function_name(sym, dso):
+        if sym is None:
+            sym = '[unknown]'
+
+        sym = sym.replace(';', ':')
+        if opts.tidy_java:
+            # the original stackcollapse-perf.pl script gives the
+            # example of converting this:
+            #    Lorg/mozilla/javascript/MemberBox;.<init>(Ljava/lang/reflect/Method;)V
+            # to this:
+            #    org/mozilla/javascript/MemberBox:.init
+            sym = sym.replace('<', '')
+            sym = sym.replace('>', '')
+            if sym[0] == 'L' and sym.find('/'):
+                sym = sym[1:]
+            try:
+                sym = sym[:sym.index('(')]
+            except ValueError:
+                pass
+
+        if opts.annotate_kernel and dso == '[kernel.kallsyms]':
+            return sym + '_[k]'
+        else:
+            return sym
+
+    stack = list()
+    if 'callchain' in param_dict:
+        for entry in param_dict['callchain']:
+            entry.setdefault('sym', dict())
+            entry['sym'].setdefault('name', None)
+            entry.setdefault('dso', None)
+            stack.append(tidy_function_name(entry['sym']['name'],
+                                            entry['dso']))
+    else:
+        param_dict.setdefault('symbol', None)
+        param_dict.setdefault('dso', None)
+        stack.append(tidy_function_name(param_dict['symbol'],
+                                        param_dict['dso']))
+
+    if opts.include_comm:
+        comm = param_dict["comm"].replace(' ', '_')
+        sep = "-"
+        if opts.include_pid:
+            comm = comm + sep + str(param_dict['sample']['pid'])
+            sep = "/"
+        if opts.include_tid:
+            comm = comm + sep + str(param_dict['sample']['tid'])
+        stack.append(comm)
+
+    stack_string = ';'.join(reversed(stack))
+    lines[stack_string] = lines[stack_string] + 1
+
+def trace_end():
+    list = lines.keys()
+    list.sort()
+    for stack in list:
+        print "%s %d" % (stack, lines[stack])