v8/tools/callstats.py

#!/usr/bin/env python
# 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.
'''
Usage: callstats.py [-h] <command> ...

Optional arguments:
  -h, --help  show this help message and exit

Commands:
  run         run chrome with --runtime-call-stats and generate logs
  stats       process logs and print statistics
  json        process logs from several versions and generate JSON
  help        help information

For each command, you can try ./runtime-call-stats.py help command.
'''

# for py2/py3 compatibility
from __future__ import print_function

import argparse
import json
import os
import re
import shutil
import subprocess
import sys
import tempfile
import operator
from callstats_groups import RUNTIME_CALL_STATS_GROUPS

import numpy
import scipy
import scipy.stats
from math import sqrt


MAX_NOF_RETRIES = 5


# Run benchmarks.

def print_command(cmd_args):
  def fix_for_printing(arg):
    m = re.match(r'^--([^=]+)=(.*)$', arg)
    if m and (' ' in m.group(2) or m.group(2).startswith('-')):
      arg = "--{}='{}'".format(m.group(1), m.group(2))
    elif ' ' in arg:
      arg = "'{}'".format(arg)
    return arg
  print(" ".join(map(fix_for_printing, cmd_args)))


def start_replay_server(args, sites, discard_output=True):
  with tempfile.NamedTemporaryFile(prefix='callstats-inject-', suffix='.js',
                                   mode='wt', delete=False) as f:
    injection = f.name
    generate_injection(f, sites, args.refresh)
  http_port = 4080 + args.port_offset
  https_port = 4443 + args.port_offset
  cmd_args = [
      args.replay_bin,
      "--port=%s" % http_port,
      "--ssl_port=%s" % https_port,
      "--no-dns_forwarding",
      "--use_closest_match",
      "--no-diff_unknown_requests",
      "--inject_scripts=deterministic.js,{}".format(injection),
      args.replay_wpr,
  ]
  print("=" * 80)
  print_command(cmd_args)
  if discard_output:
    with open(os.devnull, 'w') as null:
      server = subprocess.Popen(cmd_args, stdout=null, stderr=null)
  else:
      server = subprocess.Popen(cmd_args)
  print("RUNNING REPLAY SERVER: %s with PID=%s" % (args.replay_bin, server.pid))
  print("=" * 80)
  return {'process': server, 'injection': injection}


def stop_replay_server(server):
  print("SHUTTING DOWN REPLAY SERVER %s" % server['process'].pid)
  server['process'].terminate()
  os.remove(server['injection'])


def generate_injection(f, sites, refreshes=0):
  print("""\
(function() {
  var s = window.sessionStorage.getItem("refreshCounter");
  var refreshTotal = """, refreshes, """;
  var refreshCounter = s ? parseInt(s) : refreshTotal;
  var refreshId = refreshTotal - refreshCounter;
  if (refreshCounter > 0) {
    window.sessionStorage.setItem("refreshCounter", refreshCounter-1);
  }
  function match(url, item) {
    if ('regexp' in item) { return url.match(item.regexp) !== null };
    var url_wanted = item.url;
    /* Allow automatic redirections from http to https. */
    if (url_wanted.startsWith("http://") && url.startsWith("https://")) {
      url_wanted = "https://" + url_wanted.substr(7);
    }
    return url.startsWith(url_wanted);
  };
  function onLoad(url) {
    for (var item of sites) {
      if (!match(url, item)) continue;
      var timeout = 'timeline' in item ? 2000 * item.timeline
                  : 'timeout'  in item ? 1000 * (item.timeout - 3)
                  : 10000;
      console.log("Setting time out of " + timeout + " for: " + url);
      window.setTimeout(function() {
        console.log("Time is out for: " + url);
        var msg = "STATS: (" + refreshId + ") " + url;
        %GetAndResetRuntimeCallStats(1, msg);
        if (refreshCounter > 0) {
          console.log(
              "Refresh counter is " + refreshCounter + ", refreshing: " + url);
          window.location.reload();
        }
      }, timeout);
      return;
    }
    console.log("Ignoring: " + url);
  };
  var sites =
    """, json.dumps(sites), """;
  onLoad(window.location.href);
})();""", file=f)

def get_chrome_flags(js_flags, user_data_dir, arg_delimiter=""):
  return [
      "--no-default-browser-check",
      "--no-sandbox",
      "--disable-translate",
      "--enable-benchmarking",
      "--enable-stats-table",
      "--js-flags={}{}{}".format(arg_delimiter, js_flags, arg_delimiter),
      "--no-first-run",
      "--user-data-dir={}{}{}".format(arg_delimiter, user_data_dir,
                                      arg_delimiter),
      "--data-path={}{}{}".format(arg_delimiter,
          os.path.join(user_data_dir, 'content-shell-data'), arg_delimiter),
    ]

def get_chrome_replay_flags(args, arg_delimiter=""):
  http_port = 4080 + args.port_offset
  https_port = 4443 + args.port_offset
  return [
      "--host-resolver-rules=%sMAP *:80 localhost:%s, "  \
                              "MAP *:443 localhost:%s, " \
                              "EXCLUDE localhost%s" % (
                               arg_delimiter, http_port, https_port,
                               arg_delimiter),
      "--ignore-certificate-errors",
      "--disable-seccomp-sandbox",
      "--disable-web-security",
      "--reduce-security-for-testing",
      "--allow-insecure-localhost",
    ]

def run_site(site, domain, args, timeout=None):
  print("="*80)
  print("RUNNING DOMAIN %s" % domain)
  print("="*80)
  result_template = "{domain}#{count}.txt" if args.repeat else "{domain}.txt"
  count = 0
  if timeout is None: timeout = args.timeout
  if args.replay_wpr:
    timeout *= 1 + args.refresh
    timeout += 1
  retries_since_good_run = 0
  while count == 0 or args.repeat is not None and count < args.repeat:
    count += 1
    result = result_template.format(domain=domain, count=count)
    retries = 0
    while args.retries is None or retries < args.retries:
      retries += 1
      try:
        if args.user_data_dir:
          user_data_dir = args.user_data_dir
        else:
          user_data_dir = tempfile.mkdtemp(prefix="chr_")
        js_flags = "--runtime-call-stats"
        if args.replay_wpr: js_flags += " --allow-natives-syntax"
        if args.js_flags: js_flags += " " + args.js_flags
        chrome_flags = get_chrome_flags(js_flags, user_data_dir)
        if args.replay_wpr:
          chrome_flags += get_chrome_replay_flags(args)
        else:
          chrome_flags += [ "--single-process", ]
        if args.chrome_flags:
          chrome_flags += args.chrome_flags.split()
        cmd_args = [
            "timeout", str(timeout),
            args.with_chrome
        ] + chrome_flags + [ site ]
        print("- " * 40)
        print_command(cmd_args)
        print("- " * 40)
        with open(result, "wt") as f:
          with open(args.log_stderr or os.devnull, 'at') as err:
            status = subprocess.call(cmd_args, stdout=f, stderr=err)
        # 124 means timeout killed chrome, 0 means the user was bored first!
        # If none of these two happened, then chrome apparently crashed, so
        # it must be called again.
        if status != 124 and status != 0:
          print("CHROME CRASHED, REPEATING RUN");
          continue
        # If the stats file is empty, chrome must be called again.
        if os.path.isfile(result) and os.path.getsize(result) > 0:
          if args.print_url:
            with open(result, "at") as f:
              print(file=f)
              print("URL: {}".format(site), file=f)
          retries_since_good_run = 0
          break
        if retries_since_good_run > MAX_NOF_RETRIES:
          # Abort after too many retries, no point in ever increasing the
          # timeout.
          print("TOO MANY EMPTY RESULTS ABORTING RUN")
          return
        timeout += 2 ** retries_since_good_run
        retries_since_good_run += 1
        print("EMPTY RESULT, REPEATING RUN ({})".format(
            retries_since_good_run));
      finally:
        if not args.user_data_dir:
          shutil.rmtree(user_data_dir)


def read_sites_file(args):
  try:
    sites = []
    try:
      with open(args.sites_file, "rt") as f:
        for item in json.load(f):
          if 'timeout' not in item:
            # This is more-or-less arbitrary.
            item['timeout'] = int(1.5 * item['timeline'] + 7)
          if item['timeout'] > args.timeout: item['timeout'] = args.timeout
          sites.append(item)
    except ValueError:
      args.error("Warning: Could not read sites file as JSON, falling back to "
                 "primitive file")
      with open(args.sites_file, "rt") as f:
        for line in f:
          line = line.strip()
          if not line or line.startswith('#'): continue
          sites.append({'url': line, 'timeout': args.timeout})
    return sites
  except IOError as e:
    args.error("Cannot read from {}. {}.".format(args.sites_file, e.strerror))
    sys.exit(1)


def read_sites(args):
  # Determine the websites to benchmark.
  if args.sites_file:
    return read_sites_file(args)
  return [{'url': site, 'timeout': args.timeout} for site in args.sites]

def do_run(args):
  sites = read_sites(args)
  replay_server = start_replay_server(args, sites) if args.replay_wpr else None
  # Disambiguate domains, if needed.
  L = []
  domains = {}
  for item in sites:
    site = item['url']
    domain = None
    if args.domain:
      domain = args.domain
    elif 'domain' in item:
      domain = item['domain']
    else:
      m = re.match(r'^(https?://)?([^/]+)(/.*)?$', site)
      if not m:
        args.error("Invalid URL {}.".format(site))
        continue
      domain = m.group(2)
    entry = [site, domain, None, item['timeout']]
    if domain not in domains:
      domains[domain] = entry
    else:
      if not isinstance(domains[domain], int):
        domains[domain][2] = 1
        domains[domain] = 1
      domains[domain] += 1
      entry[2] = domains[domain]
    L.append(entry)
  try:
    # Run them.
    for site, domain, count, timeout in L:
      if count is not None: domain = "{}%{}".format(domain, count)
      print((site, domain, timeout))
      run_site(site, domain, args, timeout)
  finally:
    if replay_server:
      stop_replay_server(replay_server)


def do_run_replay_server(args):
  sites = read_sites(args)
  print("- " * 40)
  print("Available URLs:")
  for site in sites:
    print("    "+site['url'])
  print("- " * 40)
  print("Launch chromium with the following commands for debugging:")
  flags = get_chrome_flags("--runtime-call-stats --allow-natives-syntax",
                           "/var/tmp/`date +%s`", '"')
  flags += get_chrome_replay_flags(args, "'")
  print("    $CHROMIUM_DIR/out/Release/chrome " + (" ".join(flags)) + " <URL>")
  print("- " * 40)
  replay_server = start_replay_server(args, sites, discard_output=False)
  try:
    replay_server['process'].wait()
  finally:
   stop_replay_server(replay_server)


# Calculate statistics.

def statistics(data):
  N = len(data)
  average = numpy.average(data)
  median = numpy.median(data)
  low = numpy.min(data)
  high= numpy.max(data)
  if N > 1:
    # evaluate sample variance by setting delta degrees of freedom (ddof) to
    # 1. The degree used in calculations is N - ddof
    stddev = numpy.std(data, ddof=1)
    # Get the endpoints of the range that contains 95% of the distribution
    t_bounds = scipy.stats.t.interval(0.95, N-1)
    #assert abs(t_bounds[0] + t_bounds[1]) < 1e-6
    # sum mean to the confidence interval
    ci = {
        'abs': t_bounds[1] * stddev / sqrt(N),
        'low': average + t_bounds[0] * stddev / sqrt(N),
        'high': average + t_bounds[1] * stddev / sqrt(N)
    }
  else:
    stddev = 0
    ci = { 'abs': 0, 'low': average, 'high': average }
  if abs(stddev) > 0.0001 and abs(average) > 0.0001:
    ci['perc'] = t_bounds[1] * stddev / sqrt(N) / average * 100
  else:
    ci['perc'] = 0
  return { 'samples': N, 'average': average, 'median': median,
           'stddev': stddev, 'min': low, 'max': high, 'ci': ci }


def add_category_total(entries, groups, category_prefix):
  group_data = { 'time': 0, 'count': 0 }
  for group_name, regexp in groups:
    if not group_name.startswith('Group-' + category_prefix): continue
    group_data['time'] += entries[group_name]['time']
    group_data['count'] += entries[group_name]['count']
  entries['Group-' + category_prefix + '-Total'] = group_data


def read_stats(path, domain, args):
  groups = [];
  if args.aggregate:
    groups = [
        ('Group-IC', re.compile(".*IC_.*")),
        ('Group-OptimizeBackground', re.compile(".*OptimizeBackground.*")),
        ('Group-Optimize',
         re.compile("StackGuard|.*Optimize.*|.*Deoptimize.*|Recompile.*")),
        ('Group-CompileBackground', re.compile("(.*CompileBackground.*)")),
        ('Group-Compile', re.compile("(^Compile.*)|(.*_Compile.*)")),
        ('Group-ParseBackground', re.compile(".*ParseBackground.*")),
        ('Group-Parse', re.compile(".*Parse.*")),
        ('Group-Callback', re.compile(".*Callback.*")),
        ('Group-API', re.compile(".*API.*")),
        ('Group-GC-Custom', re.compile("GC_Custom_.*")),
        ('Group-GC-Background', re.compile(".*GC.*BACKGROUND.*")),
        ('Group-GC', re.compile("GC_.*|AllocateInTargetSpace")),
        ('Group-JavaScript', re.compile("JS_Execution")),
        ('Group-Runtime', re.compile(".*"))]
  with open(path, "rt") as f:
    # Process the whole file and sum repeating entries.
    entries = { 'Sum': {'time': 0, 'count': 0} }
    for group_name, regexp in groups:
      entries[group_name] = { 'time': 0, 'count': 0 }
    for line in f:
      line = line.strip()
      # Discard headers and footers.
      if not line: continue
      if line.startswith("Runtime Function"): continue
      if line.startswith("===="): continue
      if line.startswith("----"): continue
      if line.startswith("URL:"): continue
      if line.startswith("STATS:"): continue
      # We have a regular line.
      fields = line.split()
      key = fields[0]
      time = float(fields[1].replace("ms", ""))
      count = int(fields[3])
      if key not in entries: entries[key] = { 'time': 0, 'count': 0 }
      entries[key]['time'] += time
      entries[key]['count'] += count
      # We calculate the sum, if it's not the "total" line.
      if key != "Total":
        entries['Sum']['time'] += time
        entries['Sum']['count'] += count
        for group_name, regexp in groups:
          if not regexp.match(key): continue
          entries[group_name]['time'] += time
          entries[group_name]['count'] += count
          break
    # Calculate the V8-Total (all groups except Callback)
    group_data = { 'time': 0, 'count': 0 }
    for group_name, regexp in groups:
      if group_name == 'Group-Callback': continue
      group_data['time'] += entries[group_name]['time']
      group_data['count'] += entries[group_name]['count']
    entries['Group-Total-V8'] = group_data
    # Calculate the Parse-Total, Compile-Total and Optimize-Total groups
    add_category_total(entries, groups, 'Parse')
    add_category_total(entries, groups, 'Compile')
    add_category_total(entries, groups, 'Optimize')
    # Append the sums as single entries to domain.
    for key in entries:
      if key not in domain: domain[key] = { 'time_list': [], 'count_list': [] }
      domain[key]['time_list'].append(entries[key]['time'])
      domain[key]['count_list'].append(entries[key]['count'])


def print_stats(S, args):
  # Sort by ascending/descending time average, then by ascending/descending
  # count average, then by ascending name.
  def sort_asc_func(item):
    return (item[1]['time_stat']['average'],
            item[1]['count_stat']['average'],
            item[0])
  def sort_desc_func(item):
    return (-item[1]['time_stat']['average'],
            -item[1]['count_stat']['average'],
            item[0])
  # Sorting order is in the commend-line arguments.
  sort_func = sort_asc_func if args.sort == "asc" else sort_desc_func
  # Possibly limit how many elements to print.
  L = [item for item in sorted(S.items(), key=sort_func)
       if item[0] not in ["Total", "Sum"]]
  N = len(L)
  if args.limit == 0:
    low, high = 0, N
  elif args.sort == "desc":
    low, high = 0, args.limit
  else:
    low, high = N-args.limit, N
  # How to print entries.
  def print_entry(key, value):
    def stats(s, units=""):
      conf = "{:0.1f}({:0.2f}%)".format(s['ci']['abs'], s['ci']['perc'])
      return "{:8.1f}{} +/- {:15s}".format(s['average'], units, conf)
    print("{:>50s}  {}  {}".format(
      key,
      stats(value['time_stat'], units="ms"),
      stats(value['count_stat'])
    ))
  # Print and calculate partial sums, if necessary.
  for i in range(low, high):
    print_entry(*L[i])
    if args.totals and args.limit != 0 and not args.aggregate:
      if i == low:
        partial = { 'time_list': [0] * len(L[i][1]['time_list']),
                    'count_list': [0] * len(L[i][1]['count_list']) }
      assert len(partial['time_list']) == len(L[i][1]['time_list'])
      assert len(partial['count_list']) == len(L[i][1]['count_list'])
      for j, v in enumerate(L[i][1]['time_list']):
        partial['time_list'][j] += v
      for j, v in enumerate(L[i][1]['count_list']):
        partial['count_list'][j] += v
  # Print totals, if necessary.
  if args.totals:
    print('-' * 80)
    if args.limit != 0 and not args.aggregate:
      partial['time_stat'] = statistics(partial['time_list'])
      partial['count_stat'] = statistics(partial['count_list'])
      print_entry("Partial", partial)
    print_entry("Sum", S["Sum"])
    print_entry("Total", S["Total"])


def do_stats(args):
  domains = {}
  for path in args.logfiles:
    filename = os.path.basename(path)
    m = re.match(r'^([^#]+)(#.*)?$', filename)
    domain = m.group(1)
    if domain not in domains: domains[domain] = {}
    read_stats(path, domains[domain], args)
  if args.aggregate:
    create_total_page_stats(domains, args)
  for i, domain in enumerate(sorted(domains)):
    if len(domains) > 1:
      if i > 0: print()
      print("{}:".format(domain))
      print('=' * 80)
    domain_stats = domains[domain]
    for key in domain_stats:
      domain_stats[key]['time_stat'] = \
          statistics(domain_stats[key]['time_list'])
      domain_stats[key]['count_stat'] = \
          statistics(domain_stats[key]['count_list'])
    print_stats(domain_stats, args)


# Create a Total page with all entries summed up.
def create_total_page_stats(domains, args):
  total = {}
  def sum_up(parent, key, other):
    sums = parent[key]
    for i, item in enumerate(other[key]):
      if i >= len(sums):
        sums.extend([0] * (i - len(sums) + 1))
      if item is not None:
        sums[i] += item
  # Exclude adwords and speedometer pages from aggrigate total, since adwords
  # dominates execution time and speedometer is measured elsewhere.
  excluded_domains = ['adwords.google.com', 'speedometer-angular',
                      'speedometer-jquery', 'speedometer-backbone',
                      'speedometer-ember', 'speedometer-vanilla'];
  # Sum up all the entries/metrics from all non-excluded domains
  for domain, entries in domains.items():
    if domain in excluded_domains:
      continue;
    for key, domain_stats in entries.items():
      if key not in total:
        total[key] = {}
        total[key]['time_list'] = list(domain_stats['time_list'])
        total[key]['count_list'] = list(domain_stats['count_list'])
      else:
        sum_up(total[key], 'time_list', domain_stats)
        sum_up(total[key], 'count_list', domain_stats)
  # Add a new "Total" page containing the summed up metrics.
  domains['Total'] = total

# Generate Raw JSON file.

def _read_logs(args):
  versions = {}
  for path in args.logdirs:
    if os.path.isdir(path):
      for root, dirs, files in os.walk(path):
        version = os.path.basename(root)
        if version not in versions: versions[version] = {}
        for filename in files:
          if filename.endswith(".txt"):
            m = re.match(r'^([^#]+)(#.*)?\.txt$', filename)
            domain = m.group(1)
            if domain not in versions[version]: versions[version][domain] = {}
            read_stats(os.path.join(root, filename),
                       versions[version][domain], args)

  return versions

def do_raw_json(args):
  versions = _read_logs(args)

  for version, domains in versions.items():
    if args.aggregate:
      create_total_page_stats(domains, args)
    for domain, entries in domains.items():
      raw_entries = []
      for name, value in entries.items():
        # We don't want the calculated sum in the JSON file.
        if name == "Sum": continue
        raw_entries.append({
          'name': name,
          'duration': value['time_list'],
          'count': value['count_list'],
        })

      domains[domain] = raw_entries

  print(json.dumps(versions, separators=(',', ':')))


# Generate JSON file.

def do_json(args):
  versions = _read_logs(args)

  for version, domains in versions.items():
    if args.aggregate:
      create_total_page_stats(domains, args)
    for domain, entries in domains.items():
      stats = []
      for name, value in entries.items():
        # We don't want the calculated sum in the JSON file.
        if name == "Sum": continue
        entry = [name]
        for x in ['time_list', 'count_list']:
          s = statistics(entries[name][x])
          entry.append(round(s['average'], 1))
          entry.append(round(s['ci']['abs'], 1))
          entry.append(round(s['ci']['perc'], 2))
        stats.append(entry)
      domains[domain] = stats
  print(json.dumps(versions, separators=(',', ':')))


# Help.

def do_help(parser, subparsers, args):
  if args.help_cmd:
    if args.help_cmd in subparsers:
      subparsers[args.help_cmd].print_help()
    else:
      args.error("Unknown command '{}'".format(args.help_cmd))
  else:
    parser.print_help()


# Main program, parse command line and execute.

def coexist(*l):
  given = sum(1 for x in l if x)
  return given == 0 or given == len(l)

def main():
  parser = argparse.ArgumentParser()
  subparser_adder = parser.add_subparsers(title="commands", dest="command",
                                          metavar="<command>")
  subparsers = {}
  # Command: run.
  subparsers["run"] = subparser_adder.add_parser(
      "run", help="Replay websites and collect runtime stats data.")
  subparsers["run"].set_defaults(
      func=do_run, error=subparsers["run"].error)
  subparsers["run"].add_argument(
      "--chrome-flags", type=str, default="",
      help="specify additional chrome flags")
  subparsers["run"].add_argument(
      "--js-flags", type=str, default="",
      help="specify additional V8 flags")
  subparsers["run"].add_argument(
      "-u", "--user-data-dir", type=str, metavar="<path>",
      help="specify user data dir (default is temporary)")
  subparsers["run"].add_argument(
      "-c", "--with-chrome", type=str, metavar="<path>",
      default="/usr/bin/google-chrome",
      help="specify chrome executable to use")
  subparsers["run"].add_argument(
      "-r", "--retries", type=int, metavar="<num>",
      help="specify retries if website is down (default: forever)")
  subparsers["run"].add_argument(
      "--no-url", dest="print_url", action="store_false", default=True,
      help="do not include url in statistics file")
  subparsers["run"].add_argument(
      "--domain", type=str, default="",
      help="specify the output file domain name")
  subparsers["run"].add_argument(
      "-n", "--repeat", type=int, metavar="<num>",
      help="specify iterations for each website (default: once)")

  def add_replay_args(subparser):
    subparser.add_argument(
        "-k", "--refresh", type=int, metavar="<num>", default=0,
        help="specify refreshes for each iteration (default: 0)")
    subparser.add_argument(
        "--replay-wpr", type=str, metavar="<path>",
        help="use the specified web page replay (.wpr) archive")
    subparser.add_argument(
        "--replay-bin", type=str, metavar="<path>",
        help="specify the replay.py script typically located in " \
             "$CHROMIUM/src/third_party/webpagereplay/replay.py")
    subparser.add_argument(
        "-f", "--sites-file", type=str, metavar="<path>",
        help="specify file containing benchmark websites")
    subparser.add_argument(
        "-t", "--timeout", type=int, metavar="<seconds>", default=60,
        help="specify seconds before chrome is killed")
    subparser.add_argument(
        "-p", "--port-offset", type=int, metavar="<offset>", default=0,
        help="specify the offset for the replay server's default ports")
    subparser.add_argument(
        "-l", "--log-stderr", type=str, metavar="<path>",
        help="specify where chrome's stderr should go (default: /dev/null)")
    subparser.add_argument(
        "--sites", type=str, metavar="<URL>", nargs="*",
        help="specify benchmark website")
  add_replay_args(subparsers["run"])

  # Command: replay-server
  subparsers["replay"] = subparser_adder.add_parser(
      "replay", help="Run the replay server for debugging purposes")
  subparsers["replay"].set_defaults(
      func=do_run_replay_server, error=subparsers["replay"].error)
  add_replay_args(subparsers["replay"])

  # Command: stats.
  subparsers["stats"] = subparser_adder.add_parser(
      "stats", help="Analize the results file create by the 'run' command.")
  subparsers["stats"].set_defaults(
      func=do_stats, error=subparsers["stats"].error)
  subparsers["stats"].add_argument(
      "-l", "--limit", type=int, metavar="<num>", default=0,
      help="limit how many items to print (default: none)")
  subparsers["stats"].add_argument(
      "-s", "--sort", choices=["asc", "desc"], default="asc",
      help="specify sorting order (default: ascending)")
  subparsers["stats"].add_argument(
      "-n", "--no-total", dest="totals", action="store_false", default=True,
      help="do not print totals")
  subparsers["stats"].add_argument(
      "logfiles", type=str, metavar="<logfile>", nargs="*",
      help="specify log files to parse")
  subparsers["stats"].add_argument(
      "--aggregate", dest="aggregate", action="store_true", default=False,
      help="Create aggregated entries. Adds Group-* entries at the toplevel. " \
      "Additionally creates a Total page with all entries.")

  # Command: json.
  subparsers["json"] = subparser_adder.add_parser(
      "json", help="Collect results file created by the 'run' command into" \
          "a single json file.")
  subparsers["json"].set_defaults(
      func=do_json, error=subparsers["json"].error)
  subparsers["json"].add_argument(
      "logdirs", type=str, metavar="<logdir>", nargs="*",
      help="specify directories with log files to parse")
  subparsers["json"].add_argument(
      "--aggregate", dest="aggregate", action="store_true", default=False,
      help="Create aggregated entries. Adds Group-* entries at the toplevel. " \
      "Additionally creates a Total page with all entries.")

  # Command: raw-json.
  subparsers["raw-json"] = subparser_adder.add_parser(
      "raw-json", help="Collect raw results from 'run' command into" \
          "a single json file.")
  subparsers["raw-json"].set_defaults(
      func=do_raw_json, error=subparsers["json"].error)
  subparsers["raw-json"].add_argument(
      "logdirs", type=str, metavar="<logdir>", nargs="*",
      help="specify directories with log files to parse")
  subparsers["raw-json"].add_argument(
      "--aggregate", dest="aggregate", action="store_true", default=False,
      help="Create aggregated entries. Adds Group-* entries at the toplevel. " \
      "Additionally creates a Total page with all entries.")

  # Command: help.
  subparsers["help"] = subparser_adder.add_parser(
      "help", help="help information")
  subparsers["help"].set_defaults(
      func=lambda args: do_help(parser, subparsers, args),
      error=subparsers["help"].error)
  subparsers["help"].add_argument(
      "help_cmd", type=str, metavar="<command>", nargs="?",
      help="command for which to display help")

  # Execute the command.
  args = parser.parse_args()
  setattr(args, 'script_path', os.path.dirname(sys.argv[0]))
  if args.command == "run" and coexist(args.sites_file, args.sites):
    args.error("use either option --sites-file or site URLs")
    sys.exit(1)
  elif args.command == "run" and not coexist(args.replay_wpr, args.replay_bin):
    args.error("options --replay-wpr and --replay-bin must be used together")
    sys.exit(1)
  else:
    args.func(args)

if __name__ == "__main__":
  sys.exit(main())