[Interpreter] Add Ignition profile visualization tool.

tools/ignition/linux_perf_report.py

Index: tools/ignition/linux_perf_report.py
diff --git a/tools/ignition/linux_perf_report.py b/tools/ignition/linux_perf_report.py
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+++ b/tools/ignition/linux_perf_report.py
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+#! /usr/bin/python2
+#
+# 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 argparse
+import collections
+import re
+import subprocess
+import sys
+
+
+__DESCRIPTION = """
+Processes a perf.data sample file and reports the hottest Ignition bytecodes,
+or write an input file for flamegraph.pl.
+"""
+
+
+__HELP_EPILOGUE = """
+examples:
+  # Get a flamegraph for Ignition bytecode handlers on Octane benchmark,
+  # without considering the time spent compiling JS code, entry trampoline
+  # samples and other non-Ignition samples.
+  #
+  $ tools/run-perf.sh out/x64.release/d8 \\
+        --ignition --noturbo --nocrankshaft run.js
+  $ tools/ignition/linux_perf_report.py --flamegraph -o out.collapsed
+  $ flamegraph.pl --colors js out.collapsed > out.svg
+
+  # Same as above, but show all samples, including time spent compiling JS code,
+  # entry trampoline samples and other samples.
+  $ # ...
+  $ tools/ignition/linux_perf_report.py \\
+      --flamegraph --show-all -o out.collapsed
+  $ # ...
+
+  # Same as above, but show full function signatures in the flamegraph.
+  $ # ...
+  $ tools/ignition/linux_perf_report.py \\
+      --flamegraph --show-full-signatures -o out.collapsed
+  $ # ...
+
+  # See the hottest bytecodes on Octane benchmark, by number of samples.
+  #
+  $ tools/run-perf.sh out/x64.release/d8 \\
+        --ignition --noturbo --nocrankshaft octane/run.js
+  $ tools/ignition/linux_perf_report.py
+"""
+
+
+COMPILER_SYMBOLS_RE = re.compile(
+  r"v8::internal::(?:\(anonymous namespace\)::)?Compile|v8::internal::Parser")
+
+
+def strip_function_parameters(symbol):
+  if symbol[-1] != ')': return symbol
+  pos = 1
+  parenthesis_count = 0
+  for c in reversed(symbol):
+    if c == ')':
+      parenthesis_count += 1
+    elif c == '(':
+      parenthesis_count -= 1
+    if parenthesis_count == 0:
+      break
+    else:
+      pos += 1
+  return symbol[:-pos]
+
+
+def collapsed_callchains_generator(perf_stream, show_all=False,
+                                   show_full_signatures=False):
+  current_chain = []
+  skip_until_end_of_chain = False
+  compiler_symbol_in_chain = False
+
+  for line in perf_stream:
+    # Lines starting with a "#" are comments, skip them.
+    if line[0] == "#":
+      continue
+
+    line = line.strip()
+
+    # Empty line signals the end of the callchain.
+    if not line:
+      if not skip_until_end_of_chain and current_chain and show_all:
+        current_chain.append("[other]")
+        yield current_chain
+      # Reset parser status.
+      current_chain = []
+      skip_until_end_of_chain = False
+      compiler_symbol_in_chain = False
+      continue
+
+    if skip_until_end_of_chain:
+      continue
+
+    symbol = line.split(" ", 1)[1]
+    if not show_full_signatures:
+      symbol = strip_function_parameters(symbol)
+    current_chain.append(symbol)
+
+    if symbol.startswith("BytecodeHandler:"):
+      yield current_chain
+      skip_until_end_of_chain = True
+    elif symbol == "Stub:CEntryStub" and compiler_symbol_in_chain:
+      if show_all:
+        current_chain[-1] = "[compiler]"
+        yield current_chain
+      skip_until_end_of_chain = True
+    elif COMPILER_SYMBOLS_RE.match(symbol):
+      compiler_symbol_in_chain = True
+    elif symbol == "Builtin:InterpreterEntryTrampoline":
+      if len(current_chain) == 1:
+        yield ["[entry trampoline]"]
+      elif show_all:
+        # If we see an InterpreterEntryTrampoline which is not at the top of the
+        # chain and doesn't have a BytecodeHandler above it, then we have
+        # skipped the top BytecodeHandler due to the top-level stub not building
+        # a frame. File the chain in the [misattributed] bucket.
+        current_chain[-1] = "[misattributed]"
+        yield current_chain
+      skip_until_end_of_chain = True
+
+
+def calculate_samples_count_per_callchain(callchains):
+  chain_counters = collections.defaultdict(int)
+  for callchain in callchains:
+    key = ";".join(reversed(callchain))
+    chain_counters[key] += 1
+  return chain_counters.items()
+
+
+def calculate_samples_count_per_handler(callchains):
+  def strip_handler_prefix_if_any(handler):
+    return handler if handler[0] == "[" else handler.split(":", 1)[1]
+
+  handler_counters = collections.defaultdict(int)
+  for callchain in callchains:
+    handler = strip_handler_prefix_if_any(callchain[-1])
+    handler_counters[handler] += 1
+  return handler_counters.items()
+
+
+def write_flamegraph_input_file(output_stream, callchains):
+  for callchain, count in calculate_samples_count_per_callchain(callchains):
+    output_stream.write("{}; {}\n".format(callchain, count))
+
+
+def write_handlers_report(output_stream, callchains):
+  handler_counters = calculate_samples_count_per_handler(callchains)
+  samples_num = sum(counter for _, counter in handler_counters)
+  # Sort by decreasing number of samples
+  handler_counters.sort(key=lambda entry: entry[1], reverse=True)
+  for bytecode_name, count in handler_counters:
+    output_stream.write(
+      "{}\t{}\t{:.3f}%\n".format(bytecode_name, count,
+                                 100. * count / samples_num))
+
+
+def parse_command_line():
+  command_line_parser = argparse.ArgumentParser(
+    formatter_class=argparse.RawDescriptionHelpFormatter,
+    description=__DESCRIPTION,
+    epilog=__HELP_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(
+    "--show-all", "-a",
+    help="show samples outside Ignition bytecode handlers",
+    action="store_true"
+  )
+  command_line_parser.add_argument(
+    "--show-full-signatures", "-s",
+    help="show full signatures instead of function names",
+    action="store_true"
+  )
+  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()
+
+  perf = subprocess.Popen(["perf", "script", "-f", "ip,sym",
+                           "-i", program_options.perf_filename],
+                          stdout=subprocess.PIPE)
+
+  callchains = collapsed_callchains_generator(
+    perf.stdout, program_options.show_all,
+    program_options.show_full_signatures)
+
+  if program_options.output_flamegraph:
+    write_flamegraph_input_file(program_options.output_stream, callchains)
+  else:
+    write_handlers_report(program_options.output_stream, callchains)
+
+
+if __name__ == "__main__":
+  main()