dedupfs added

dedupfs/get_memory_usage.py

@@ -0,0 +1,47 @@
+#!/usr/bin/python
+
+"""
+The function in this Python module determines the current memory usage of the
+current process by reading the VmSize value from /proc/$pid/status. It's based
+on the following entry in the Python cookbook:
+http://code.activestate.com/recipes/286222/
+"""
+
+import os
+
+_units = { 'KB': 1024, 'MB': 1024**2, 'GB': 1024**3 }
+_handle = _handle = open('/proc/%d/status' % os.getpid())
+
+def get_memory_usage():
+  global _proc_status, _units, _handle
+  try:
+    for line in _handle:
+      if line.startswith('VmSize:'):
+        label, count, unit = line.split()
+        return int(count) * _units[unit.upper()]
+  except:
+    return 0
+  finally:
+    _handle.seek(0)
+
+if __name__ == '__main__':
+  from my_formats import format_size
+  megabyte = 1024**2
+  counter = megabyte
+  limit = megabyte * 50
+  memory = []
+  old_memory_usage = get_memory_usage()
+  assert old_memory_usage > 0
+  while counter < limit:
+    memory.append('a' * counter)
+    msg = "I've just allocated %s and get_memory_usage() returns %s (%s more, deviation is %s)"
+    new_memory_usage = get_memory_usage()
+    difference = new_memory_usage - old_memory_usage
+    deviation = max(difference, counter) - min(difference, counter)
+    assert deviation < 1024*100
+    print msg % (format_size(counter), format_size(new_memory_usage), format_size(difference), format_size(deviation))
+    old_memory_usage = new_memory_usage
+    counter += megabyte
+  print "Stopped allocating new strings at %s" % format_size(limit)
+
+# vim: ts=2 sw=2 et