utils/lit/Util.py

   1 import os, sys
   2
   3 def detectCPUs():
   4     """
   5     Detects the number of CPUs on a system. Cribbed from pp.
   6     """
   7     # Linux, Unix and MacOS:
   8     if hasattr(os, "sysconf"):
   9         if os.sysconf_names.has_key("SC_NPROCESSORS_ONLN"):
  10             # Linux & Unix:
  11             ncpus = os.sysconf("SC_NPROCESSORS_ONLN")
  12             if isinstance(ncpus, int) and ncpus > 0:
  13                 return ncpus
  14         else: # OSX:
  15             return int(os.popen2("sysctl -n hw.ncpu")[1].read())
  16     # Windows:
  17     if os.environ.has_key("NUMBER_OF_PROCESSORS"):
  18         ncpus = int(os.environ["NUMBER_OF_PROCESSORS"]);
  19         if ncpus > 0:
  20             return ncpus
  21     return 1 # Default
  22
  23 def mkdir_p(path):
  24     """mkdir_p(path) - Make the "path" directory, if it does not exist; this
  25     will also make directories for any missing parent directories."""
  26     import errno
  27
  28     if not path or os.path.exists(path):
  29         return
  30
  31     parent = os.path.dirname(path)
  32     if parent != path:
  33         mkdir_p(parent)
  34
  35     try:
  36         os.mkdir(path)
  37     except OSError,e:
  38         # Ignore EEXIST, which may occur during a race condition.
  39         if e.errno != errno.EEXIST:
  40             raise
  41
  42 def capture(args):
  43     import subprocess
  44     """capture(command) - Run the given command (or argv list) in a shell and
  45     return the standard output."""
  46     p = subprocess.Popen(args, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
  47     out,_ = p.communicate()
  48     return out
  49
  50 def which(command, paths = None):
  51     """which(command, [paths]) - Look up the given command in the paths string
  52     (or the PATH environment variable, if unspecified)."""
  53
  54     if paths is None:
  55         paths = os.environ.get('PATH','')
  56
  57     # Check for absolute match first.
  58     if os.path.exists(command):
  59         return command
  60
  61     # Would be nice if Python had a lib function for this.
  62     if not paths:
  63         paths = os.defpath
  64
  65     # Get suffixes to search.
  66     pathext = os.environ.get('PATHEXT', '').split(os.pathsep)
  67
  68     # Search the paths...
  69     for path in paths.split(os.pathsep):
  70         for ext in pathext:
  71             p = os.path.join(path, command + ext)
  72             if os.path.exists(p):
  73                 return p
  74
  75     return None
  76
  77 def printHistogram(items, title = 'Items'):
  78     import itertools, math
  79
  80     items.sort(key = lambda (_,v): v)
  81
  82     maxValue = max([v for _,v in items])
  83
  84     # Select first "nice" bar height that produces more than 10 bars.
  85     power = int(math.ceil(math.log(maxValue, 10)))
  86     for inc in itertools.cycle((5, 2, 2.5, 1)):
  87         barH = inc * 10**power
  88         N = int(math.ceil(maxValue / barH))
  89         if N > 10:
  90             break
  91         elif inc == 1:
  92             power -= 1
  93
  94     histo = [set() for i in range(N)]
  95     for name,v in items:
  96         bin = min(int(N * v/maxValue), N-1)
  97         histo[bin].add(name)
  98
  99     barW = 40
 100     hr = '-' * (barW + 34)
 101     print '\nSlowest %s:' % title
 102     print hr
 103     for name,value in items[-20:]:
 104         print '%.2fs: %s' % (value, name)
 105     print '\n%s Times:' % title
 106     print hr
 107     pDigits = int(math.ceil(math.log(maxValue, 10)))
 108     pfDigits = max(0, 3-pDigits)
 109     if pfDigits:
 110         pDigits += pfDigits + 1
 111     cDigits = int(math.ceil(math.log(len(items), 10)))
 112     print "[%s] :: [%s] :: [%s]" % ('Range'.center((pDigits+1)*2 + 3),
 113                                     'Percentage'.center(barW),
 114                                     'Count'.center(cDigits*2 + 1))
 115     print hr
 116     for i,row in enumerate(histo):
 117         pct = float(len(row)) / len(items)
 118         w = int(barW * pct)
 119         print "[%*.*fs,%*.*fs)" % (pDigits, pfDigits, i*barH,
 120                                    pDigits, pfDigits, (i+1)*barH),
 121         print ":: [%s%s] :: [%*d/%*d]" % ('*'*w, ' '*(barW-w),
 122                                           cDigits, len(row),
 123                                           cDigits, len(items))
 124