perf-helper.py revision 1.1.1.1 
1#===- perf-helper.py - Clang Python Bindings -----------------*- python -*--===#
2#
3# Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4# See https://llvm.org/LICENSE.txt for license information.
5# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6#
7#===------------------------------------------------------------------------===#
8
9from __future__ import absolute_import, division, print_function
10
11import sys
12import os
13import subprocess
14import argparse
15import time
16import bisect
17import shlex
18import tempfile
19
20test_env = { 'PATH'    : os.environ['PATH'] }
21
22def findFilesWithExtension(path, extension):
23  filenames = []
24  for root, dirs, files in os.walk(path):
25    for filename in files:
26      if filename.endswith(extension):
27        filenames.append(os.path.join(root, filename))
28  return filenames
29
30def clean(args):
31  if len(args) != 2:
32    print('Usage: %s clean <path> <extension>\n' % __file__ +
33      '\tRemoves all files with extension from <path>.')
34    return 1
35  for filename in findFilesWithExtension(args[0], args[1]):
36    os.remove(filename)
37  return 0
38
39def merge(args):
40  if len(args) != 3:
41    print('Usage: %s clean <llvm-profdata> <output> <path>\n' % __file__ +
42      '\tMerges all profraw files from path into output.')
43    return 1
44  cmd = [args[0], 'merge', '-o', args[1]]
45  cmd.extend(findFilesWithExtension(args[2], "profraw"))
46  subprocess.check_call(cmd)
47  return 0
48
49def dtrace(args):
50  parser = argparse.ArgumentParser(prog='perf-helper dtrace',
51    description='dtrace wrapper for order file generation')
52  parser.add_argument('--buffer-size', metavar='size', type=int, required=False,
53    default=1, help='dtrace buffer size in MB (default 1)')
54  parser.add_argument('--use-oneshot', required=False, action='store_true',
55    help='Use dtrace\'s oneshot probes')
56  parser.add_argument('--use-ustack', required=False, action='store_true',
57    help='Use dtrace\'s ustack to print function names')
58  parser.add_argument('--cc1', required=False, action='store_true',
59    help='Execute cc1 directly (don\'t profile the driver)')
60  parser.add_argument('cmd', nargs='*', help='')
61
62  # Use python's arg parser to handle all leading option arguments, but pass
63  # everything else through to dtrace
64  first_cmd = next(arg for arg in args if not arg.startswith("--"))
65  last_arg_idx = args.index(first_cmd)
66
67  opts = parser.parse_args(args[:last_arg_idx])
68  cmd = args[last_arg_idx:]
69
70  if opts.cc1:
71    cmd = get_cc1_command_for_args(cmd, test_env)
72
73  if opts.use_oneshot:
74      target = "oneshot$target:::entry"
75  else:
76      target = "pid$target:::entry"
77  predicate = '%s/probemod=="%s"/' % (target, os.path.basename(cmd[0]))
78  log_timestamp = 'printf("dtrace-TS: %d\\n", timestamp)'
79  if opts.use_ustack:
80      action = 'ustack(1);'
81  else:
82      action = 'printf("dtrace-Symbol: %s\\n", probefunc);'
83  dtrace_script = "%s { %s; %s }" % (predicate, log_timestamp, action)
84
85  dtrace_args = []
86  if not os.geteuid() == 0:
87    print(
88      'Script must be run as root, or you must add the following to your sudoers:'
89      + '%%admin ALL=(ALL) NOPASSWD: /usr/sbin/dtrace')
90    dtrace_args.append("sudo")
91
92  dtrace_args.extend((
93      'dtrace', '-xevaltime=exec',
94      '-xbufsize=%dm' % (opts.buffer_size),
95      '-q', '-n', dtrace_script,
96      '-c', ' '.join(cmd)))
97
98  if sys.platform == "darwin":
99    dtrace_args.append('-xmangled')
100
101  start_time = time.time()
102
103  with open("%d.dtrace" % os.getpid(), "w") as f:
104    f.write("### Command: %s" % dtrace_args)
105    subprocess.check_call(dtrace_args, stdout=f, stderr=subprocess.PIPE)
106
107  elapsed = time.time() - start_time
108  print("... data collection took %.4fs" % elapsed)
109
110  return 0
111
112def get_cc1_command_for_args(cmd, env):
113  # Find the cc1 command used by the compiler. To do this we execute the
114  # compiler with '-###' to figure out what it wants to do.
115  cmd = cmd + ['-###']
116  cc_output = subprocess.check_output(cmd, stderr=subprocess.STDOUT, env=env, universal_newlines=True).strip()
117  cc_commands = []
118  for ln in cc_output.split('\n'):
119      # Filter out known garbage.
120      if (ln == 'Using built-in specs.' or
121          ln.startswith('Configured with:') or
122          ln.startswith('Target:') or
123          ln.startswith('Thread model:') or
124          ln.startswith('InstalledDir:') or
125          ln.startswith('LLVM Profile Note') or
126          ' version ' in ln):
127          continue
128      cc_commands.append(ln)
129
130  if len(cc_commands) != 1:
131      print('Fatal error: unable to determine cc1 command: %r' % cc_output)
132      exit(1)
133
134  cc1_cmd = shlex.split(cc_commands[0])
135  if not cc1_cmd:
136      print('Fatal error: unable to determine cc1 command: %r' % cc_output)
137      exit(1)
138
139  return cc1_cmd
140
141def cc1(args):
142  parser = argparse.ArgumentParser(prog='perf-helper cc1',
143    description='cc1 wrapper for order file generation')
144  parser.add_argument('cmd', nargs='*', help='')
145
146  # Use python's arg parser to handle all leading option arguments, but pass
147  # everything else through to dtrace
148  first_cmd = next(arg for arg in args if not arg.startswith("--"))
149  last_arg_idx = args.index(first_cmd)
150
151  opts = parser.parse_args(args[:last_arg_idx])
152  cmd = args[last_arg_idx:]
153
154  # clear the profile file env, so that we don't generate profdata
155  # when capturing the cc1 command
156  cc1_env = test_env
157  cc1_env["LLVM_PROFILE_FILE"] = os.devnull
158  cc1_cmd = get_cc1_command_for_args(cmd, cc1_env)
159
160  subprocess.check_call(cc1_cmd)
161  return 0
162
163def parse_dtrace_symbol_file(path, all_symbols, all_symbols_set,
164                             missing_symbols, opts):
165  def fix_mangling(symbol):
166    if sys.platform == "darwin":
167      if symbol[0] != '_' and symbol != 'start':
168          symbol = '_' + symbol
169    return symbol
170
171  def get_symbols_with_prefix(symbol):
172    start_index = bisect.bisect_left(all_symbols, symbol)
173    for s in all_symbols[start_index:]:
174      if not s.startswith(symbol):
175        break
176      yield s
177
178  # Extract the list of symbols from the given file, which is assumed to be
179  # the output of a dtrace run logging either probefunc or ustack(1) and
180  # nothing else. The dtrace -xdemangle option needs to be used.
181  #
182  # This is particular to OS X at the moment, because of the '_' handling.
183  with open(path) as f:
184    current_timestamp = None
185    for ln in f:
186      # Drop leading and trailing whitespace.
187      ln = ln.strip()
188      if not ln.startswith("dtrace-"):
189        continue
190
191      # If this is a timestamp specifier, extract it.
192      if ln.startswith("dtrace-TS: "):
193        _,data = ln.split(': ', 1)
194        if not data.isdigit():
195          print("warning: unrecognized timestamp line %r, ignoring" % ln,
196            file=sys.stderr)
197          continue
198        current_timestamp = int(data)
199        continue
200      elif ln.startswith("dtrace-Symbol: "):
201
202        _,ln = ln.split(': ', 1)
203        if not ln:
204          continue
205
206        # If there is a '`' in the line, assume it is a ustack(1) entry in
207        # the form of <modulename>`<modulefunc>, where <modulefunc> is never
208        # truncated (but does need the mangling patched).
209        if '`' in ln:
210          yield (current_timestamp, fix_mangling(ln.split('`',1)[1]))
211          continue
212
213        # Otherwise, assume this is a probefunc printout. DTrace on OS X
214        # seems to have a bug where it prints the mangled version of symbols
215        # which aren't C++ mangled. We just add a '_' to anything but start
216        # which doesn't already have a '_'.
217        symbol = fix_mangling(ln)
218
219        # If we don't know all the symbols, or the symbol is one of them,
220        # just return it.
221        if not all_symbols_set or symbol in all_symbols_set:
222          yield (current_timestamp, symbol)
223          continue
224
225        # Otherwise, we have a symbol name which isn't present in the
226        # binary. We assume it is truncated, and try to extend it.
227
228        # Get all the symbols with this prefix.
229        possible_symbols = list(get_symbols_with_prefix(symbol))
230        if not possible_symbols:
231          continue
232
233        # If we found too many possible symbols, ignore this as a prefix.
234        if len(possible_symbols) > 100:
235          print( "warning: ignoring symbol %r " % symbol +
236            "(no match and too many possible suffixes)", file=sys.stderr)
237          continue
238
239        # Report that we resolved a missing symbol.
240        if opts.show_missing_symbols and symbol not in missing_symbols:
241          print("warning: resolved missing symbol %r" % symbol, file=sys.stderr)
242          missing_symbols.add(symbol)
243
244        # Otherwise, treat all the possible matches as having occurred. This
245        # is an over-approximation, but it should be ok in practice.
246        for s in possible_symbols:
247          yield (current_timestamp, s)
248
249def uniq(list):
250  seen = set()
251  for item in list:
252    if item not in seen:
253      yield item
254      seen.add(item)
255
256def form_by_call_order(symbol_lists):
257  # Simply strategy, just return symbols in order of occurrence, even across
258  # multiple runs.
259  return uniq(s for symbols in symbol_lists for s in symbols)
260
261def form_by_call_order_fair(symbol_lists):
262  # More complicated strategy that tries to respect the call order across all
263  # of the test cases, instead of giving a huge preference to the first test
264  # case.
265
266  # First, uniq all the lists.
267  uniq_lists = [list(uniq(symbols)) for symbols in symbol_lists]
268
269  # Compute the successors for each list.
270  succs = {}
271  for symbols in uniq_lists:
272    for a,b in zip(symbols[:-1], symbols[1:]):
273      succs[a] = items = succs.get(a, [])
274      if b not in items:
275        items.append(b)
276
277  # Emit all the symbols, but make sure to always emit all successors from any
278  # call list whenever we see a symbol.
279  #
280  # There isn't much science here, but this sometimes works better than the
281  # more naive strategy. Then again, sometimes it doesn't so more research is
282  # probably needed.
283  return uniq(s
284    for symbols in symbol_lists
285    for node in symbols
286    for s in ([node] + succs.get(node,[])))
287
288def form_by_frequency(symbol_lists):
289  # Form the order file by just putting the most commonly occurring symbols
290  # first. This assumes the data files didn't use the oneshot dtrace method.
291
292  counts = {}
293  for symbols in symbol_lists:
294    for a in symbols:
295      counts[a] = counts.get(a,0) + 1
296
297  by_count = list(counts.items())
298  by_count.sort(key = lambda __n: -__n[1])
299  return [s for s,n in by_count]
300
301def form_by_random(symbol_lists):
302  # Randomize the symbols.
303  merged_symbols = uniq(s for symbols in symbol_lists
304                          for s in symbols)
305  random.shuffle(merged_symbols)
306  return merged_symbols
307
308def form_by_alphabetical(symbol_lists):
309  # Alphabetize the symbols.
310  merged_symbols = list(set(s for symbols in symbol_lists for s in symbols))
311  merged_symbols.sort()
312  return merged_symbols
313
314methods = dict((name[len("form_by_"):],value)
315  for name,value in locals().items() if name.startswith("form_by_"))
316
317def genOrderFile(args):
318  parser = argparse.ArgumentParser(
319    "%prog  [options] <dtrace data file directories>]")
320  parser.add_argument('input', nargs='+', help='')
321  parser.add_argument("--binary", metavar="PATH", type=str, dest="binary_path",
322    help="Path to the binary being ordered (for getting all symbols)",
323    default=None)
324  parser.add_argument("--output", dest="output_path",
325    help="path to output order file to write", default=None, required=True,
326    metavar="PATH")
327  parser.add_argument("--show-missing-symbols", dest="show_missing_symbols",
328    help="show symbols which are 'fixed up' to a valid name (requires --binary)",
329    action="store_true", default=None)
330  parser.add_argument("--output-unordered-symbols",
331    dest="output_unordered_symbols_path",
332    help="write a list of the unordered symbols to PATH (requires --binary)",
333    default=None, metavar="PATH")
334  parser.add_argument("--method", dest="method",
335    help="order file generation method to use", choices=list(methods.keys()),
336    default='call_order')
337  opts = parser.parse_args(args)
338
339  # If the user gave us a binary, get all the symbols in the binary by
340  # snarfing 'nm' output.
341  if opts.binary_path is not None:
342     output = subprocess.check_output(['nm', '-P', opts.binary_path], universal_newlines=True)
343     lines = output.split("\n")
344     all_symbols = [ln.split(' ',1)[0]
345                    for ln in lines
346                    if ln.strip()]
347     print("found %d symbols in binary" % len(all_symbols))
348     all_symbols.sort()
349  else:
350     all_symbols = []
351  all_symbols_set = set(all_symbols)
352
353  # Compute the list of input files.
354  input_files = []
355  for dirname in opts.input:
356    input_files.extend(findFilesWithExtension(dirname, "dtrace"))
357
358  # Load all of the input files.
359  print("loading from %d data files" % len(input_files))
360  missing_symbols = set()
361  timestamped_symbol_lists = [
362      list(parse_dtrace_symbol_file(path, all_symbols, all_symbols_set,
363                                    missing_symbols, opts))
364      for path in input_files]
365
366  # Reorder each symbol list.
367  symbol_lists = []
368  for timestamped_symbols_list in timestamped_symbol_lists:
369    timestamped_symbols_list.sort()
370    symbol_lists.append([symbol for _,symbol in timestamped_symbols_list])
371
372  # Execute the desire order file generation method.
373  method = methods.get(opts.method)
374  result = list(method(symbol_lists))
375
376  # Report to the user on what percentage of symbols are present in the order
377  # file.
378  num_ordered_symbols = len(result)
379  if all_symbols:
380    print("note: order file contains %d/%d symbols (%.2f%%)" % (
381      num_ordered_symbols, len(all_symbols),
382      100.*num_ordered_symbols/len(all_symbols)), file=sys.stderr)
383
384  if opts.output_unordered_symbols_path:
385    ordered_symbols_set = set(result)
386    with open(opts.output_unordered_symbols_path, 'w') as f:
387      f.write("\n".join(s for s in all_symbols if s not in ordered_symbols_set))
388
389  # Write the order file.
390  with open(opts.output_path, 'w') as f:
391    f.write("\n".join(result))
392    f.write("\n")
393
394  return 0
395
396commands = {'clean' : clean,
397  'merge' : merge,
398  'dtrace' : dtrace,
399  'cc1' : cc1,
400  'gen-order-file' : genOrderFile}
401
402def main():
403  f = commands[sys.argv[1]]
404  sys.exit(f(sys.argv[2:]))
405
406if __name__ == '__main__':
407  main()
408