1# Copyright 2013 The Chromium Authors. All rights reserved.
2# Use of this source code is governed by a BSD-style license that can be
3# found in the LICENSE file.
4
5
6class CacheControl(object):
7  _DROP_CACHES = '/proc/sys/vm/drop_caches'
8
9  def __init__(self, device):
10    self._device = device
11
12  def DropRamCaches(self):
13    """Drops the filesystem ram caches for performance testing."""
14    self._device.RunShellCommand('sync', as_root=True)
15    self._device.WriteFile(CacheControl._DROP_CACHES, '3', as_root=True)
16
17