[Interpreter] Add Ignition profile visualization tool.

tools/ignition_perf_report.py

+#! /usr/bin/python2
+#

[Michael Achenbach, 2016/03/10 11:50:36]

nit: Not sure if presubmit allows this empty comment line. We'll see.

+# Copyright 2016 the V8 project authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+#
+
+import re
+import sys
+import collections

[Michael Achenbach, 2016/03/10 11:50:36]

nit: alpha order

+import subprocess
+import argparse
+
+
+DESCRIPTION = """
+Processes a perf.data sample file and reports the hottest Ignition bytecodes,
+or write an input file for flamegraph.pl.
+"""
+
+
+EPILOGUE = """
+examples:
+  # Get a flamegraph for Ignition bytecode handlers on Octane benchmark,
+  # without considering time spent compiling JS code.
+  #
+  $ tools/run-perf.sh out/x64.release/d8 --ignition octane/run.js
+  $ tools/ignition_perf_report.py --flamegraph --hide-compile -o out.collapsed
+  $ flamegraph.pl --colors js out.collapsed > out.svg
+
+  # See the hottest bytecodes on Octane benchmark, by number of samples.
+  #
+  $ tools/run-perf.sh out/x64.release/d8 --ignition octane/run.js
+  $ tools/ignition_perf_report.py
+"""
+
+
+COMPILER_SYMBOLS_RE = re.compile(r"Builtin:Compile(?:Lazy|OptimizedConcurrent)"
+                                  "$|LazyCompile:|v8::internal::Compile")
+
+
+def yield_collapsed_callchains(perf_stream, hide_compile_time=False):
+  current_chain = []
+  keep_parsing_chain = True
+  for line in perf_stream:
+    if line[0] == "#": continue
+    line = line.strip()
+    if not line:
+      keep_parsing_chain = True
+      current_chain = []
+      continue
+    if not keep_parsing_chain: continue
+    symbol = line.split(" ", 1)[1]
+    # Strip the parameters from the signature (i.e. the parts between braces)
+    symbol = symbol[0] + symbol[1:].split("(", 1)[0]
+    current_chain.append(symbol)
+    if hide_compile_time and COMPILER_SYMBOLS_RE.match(symbol):
+      keep_parsing_chain = False
+    elif symbol.startswith("BytecodeHandler:"):
+      keep_parsing_chain = False
+      yield current_chain
+
+
+def count_callchains(perf_stream, hide_compile_time):
+  chain_counters = collections.defaultdict(int)
+  for callchain in yield_collapsed_callchains(perf_stream, hide_compile_time):
+    key = ";".join(reversed(callchain))
+    chain_counters[key] += 1
+  return chain_counters.items()
+
+
+def count_handler_samples(perf_stream, hide_compile_time):
+  handler_counters = collections.defaultdict(int)
+  for callchain in yield_collapsed_callchains(perf_stream, hide_compile_time):
+    # Strip the "BytecodeHandler:" prefix
+    handler = callchain[-1].split(":", 1)[1]

[Michael Achenbach, 2016/03/10 11:50:36]

Assuming that there is no other : in callchain[-1].

+    handler_counters[handler] += 1
+  # Sort by decreasing number of samples
+  return sorted(handler_counters.items(),
+                key=lambda entry: entry[1], reverse=True)
+
+
+def parse_command_line():
+  command_line_parser = argparse.ArgumentParser(
+    formatter_class=argparse.RawDescriptionHelpFormatter,
+    description=DESCRIPTION,
+    epilog=EPILOGUE)
+
+  command_line_parser.add_argument(
+    "perf_filename",
+    help="perf sample file to process (default: perf.data)",
+    nargs="?",
+    default="perf.data",
+    metavar="<perf filename>")
+  command_line_parser.add_argument(
+    "--flamegraph", "-f",
+    help="output an input file for flamegraph.pl, not a report",
+    action="store_true",
+    dest="output_flamegraph")
+  command_line_parser.add_argument(
+    "--hide-compile", "-c",
+    help="do not count samples inside compiler routines",
+    action="store_true",
+    dest="hide_compile_time")
+  command_line_parser.add_argument(
+    "--output", "-o",
+    help="output file name (stdout if omitted)",
+    type=argparse.FileType('wt'),
+    default=sys.stdout,
+    metavar="<output filename>",
+    dest="output_stream")
+
+  return command_line_parser.parse_args()
+
+
+def main():
+  program_options = parse_command_line()
+  output_stream = program_options.output_stream
+  perf = subprocess.Popen(["perf", "script", "-f", "ip,sym",
+                           "-i", program_options.perf_filename],
+                          stdout=subprocess.PIPE)
+
+  if program_options.output_flamegraph:
+    callchain_counters = count_callchains(perf.stdout,
+                                          program_options.hide_compile_time)
+    for callchain, count in callchain_counters:
+      output_stream.write("{} {}\n".format(callchain, count))
+  else:
+    handler_counters = count_handler_samples(perf.stdout,
+                                             program_options.hide_compile_time)
+    samples_num = sum(counter for _, counter in handler_counters)
+    for bytecode_name, count in handler_counters:
+      output_stream.write(
+        "{}\t{}\t{:.3f}%\n".format(bytecode_name, count,
+                                   100. * count / samples_num))
+
+
+if __name__ == "__main__":
+  main()