hphp/tools/perf-lib.php

   1 <?hh
   2 // Copyright 2004-present Facebook. All Rights Reserved.
   3
   4 function starts_with($str, $prefix) {
   5   return strncmp($str, $prefix, strlen($prefix)) === 0;
   6 }
   7
   8 <<__Memoize>>
   9 function filter_func_raw(string $func): string {
  10   return trim(shell_exec("echo '$func' | c++filt"));
  11 }
  12
  13 // If $func looks like a mangled C++ symbol, attempt to demangle it, stripping
  14 // off any trailing junk first.
  15 function filter_func(string $func): string {
  16   if (strncmp($func, '_Z', 2) === 0) {
  17     $matches = null;
  18     if (
  19       preg_match_with_matches('/^(.+)\.isra\.\d+$/', $func, inout $matches) ===
  20         1
  21     ) {
  22       $func = $matches[1];
  23     }
  24     return filter_func_raw($func);
  25   }
  26
  27   return $func;
  28 }
  29
  30 // Read perf samples from the given file stream into a Vector of stack traces.
  31 // The stream should contain the output of "perf script -f comm,ip,sym".
  32 function read_perf_samples($file, $desired_binary_prefix = 'hhvmworker') {
  33   $samples = Vector {};
  34   $skip_sample = false;
  35   $stack = null;
  36   $binary = null;
  37
  38   while ($line = fgets($file)) {
  39     $line = trim($line);
  40
  41     if ($line === '') {
  42       if ($stack) {
  43         $samples[] = $stack;
  44         $stack = null;
  45       }
  46       $skip_sample = false;
  47       continue;
  48     }
  49     if ($skip_sample) {
  50       continue;
  51     }
  52
  53     $matches = null;
  54     if (
  55       preg_match_with_matches('/^[a-f0-9]+ (.+)$/', $line, inout $matches) === 1
  56     ) {
  57       if (!starts_with($matches[0], "ffffffff")) { // skip kernel frames
  58         if (!$stack) $stack = Vector {};
  59         $stack[] = filter_func($matches[1]);
  60       }
  61     } else {
  62       if ($stack !== null) throw new Exception("Unexpected line $line");
  63       $binary = $line;
  64       $skip_sample = !starts_with($binary, $desired_binary_prefix);
  65     }
  66   }
  67
  68   if ($stack) $samples[] = $stack;
  69   return $samples;
  70 }