tests/qemu-iotests/093

   1 #!/usr/bin/env python
   2 #
   3 # Tests for IO throttling
   4 #
   5 # Copyright (C) 2015 Red Hat, Inc.
   6 # Copyright (C) 2015-2016 Igalia, S.L.
   7 #
   8 # This program is free software; you can redistribute it and/or modify
   9 # it under the terms of the GNU General Public License as published by
  10 # the Free Software Foundation; either version 2 of the License, or
  11 # (at your option) any later version.
  12 #
  13 # This program is distributed in the hope that it will be useful,
  14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 # GNU General Public License for more details.
  17 #
  18 # You should have received a copy of the GNU General Public License
  19 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20 #
  21
  22 import iotests
  23
  24 nsec_per_sec = 1000000000
  25
  26 class ThrottleTestCase(iotests.QMPTestCase):
  27     test_img = "null-aio://"
  28     max_drives = 3
  29
  30     def blockstats(self, device):
  31         result = self.vm.qmp("query-blockstats")
  32         for r in result['return']:
  33             if r['device'] == device:
  34                 stat = r['stats']
  35                 return stat['rd_bytes'], stat['rd_operations'], stat['wr_bytes'], stat['wr_operations']
  36         raise Exception("Device not found for blockstats: %s" % device)
  37
  38     def setUp(self):
  39         self.vm = iotests.VM()
  40         for i in range(0, self.max_drives):
  41             self.vm.add_drive(self.test_img)
  42         self.vm.launch()
  43
  44     def tearDown(self):
  45         self.vm.shutdown()
  46
  47     def configure_throttle(self, ndrives, params):
  48         params['group'] = 'test'
  49
  50         # Set the I/O throttling parameters to all drives
  51         for i in range(0, ndrives):
  52             params['device'] = 'drive%d' % i
  53             result = self.vm.qmp("block_set_io_throttle", conv_keys=False, **params)
  54             self.assert_qmp(result, 'return', {})
  55
  56     def do_test_throttle(self, ndrives, seconds, params):
  57         def check_limit(limit, num):
  58             # IO throttling algorithm is discrete, allow 10% error so the test
  59             # is more robust
  60             return limit == 0 or \
  61                    (num < seconds * limit * 1.1 / ndrives
  62                    and num > seconds * limit * 0.9 / ndrives)
  63
  64         # Set vm clock to a known value
  65         ns = seconds * nsec_per_sec
  66         self.vm.qtest("clock_step %d" % ns)
  67
  68         # Submit enough requests so the throttling mechanism kicks
  69         # in. The throttled requests won't be executed until we
  70         # advance the virtual clock.
  71         rq_size = 512
  72         rd_nr = max(params['bps'] / rq_size / 2,
  73                     params['bps_rd'] / rq_size,
  74                     params['iops'] / 2,
  75                     params['iops_rd'])
  76         rd_nr *= seconds * 2
  77         rd_nr /= ndrives
  78         wr_nr = max(params['bps'] / rq_size / 2,
  79                     params['bps_wr'] / rq_size,
  80                     params['iops'] / 2,
  81                     params['iops_wr'])
  82         wr_nr *= seconds * 2
  83         wr_nr /= ndrives
  84
  85         # Send I/O requests to all drives
  86         for i in range(rd_nr):
  87             for drive in range(0, ndrives):
  88                 self.vm.hmp_qemu_io("drive%d" % drive, "aio_read %d %d" %
  89                                     (i * rq_size, rq_size))
  90
  91         for i in range(wr_nr):
  92             for drive in range(0, ndrives):
  93                 self.vm.hmp_qemu_io("drive%d" % drive, "aio_write %d %d" %
  94                                     (i * rq_size, rq_size))
  95
  96         # We'll store the I/O stats for each drive in these arrays
  97         start_rd_bytes = [0] * ndrives
  98         start_rd_iops  = [0] * ndrives
  99         start_wr_bytes = [0] * ndrives
 100         start_wr_iops  = [0] * ndrives
 101         end_rd_bytes   = [0] * ndrives
 102         end_rd_iops    = [0] * ndrives
 103         end_wr_bytes   = [0] * ndrives
 104         end_wr_iops    = [0] * ndrives
 105
 106         # Read the stats before advancing the clock
 107         for i in range(0, ndrives):
 108             start_rd_bytes[i], start_rd_iops[i], start_wr_bytes[i], \
 109                 start_wr_iops[i] = self.blockstats('drive%d' % i)
 110
 111         self.vm.qtest("clock_step %d" % ns)
 112
 113         # Read the stats after advancing the clock
 114         for i in range(0, ndrives):
 115             end_rd_bytes[i], end_rd_iops[i], end_wr_bytes[i], \
 116                 end_wr_iops[i] = self.blockstats('drive%d' % i)
 117
 118         # Check that the I/O is within the limits and evenly distributed
 119         for i in range(0, ndrives):
 120             rd_bytes = end_rd_bytes[i] - start_rd_bytes[i]
 121             rd_iops = end_rd_iops[i] - start_rd_iops[i]
 122             wr_bytes = end_wr_bytes[i] - start_wr_bytes[i]
 123             wr_iops = end_wr_iops[i] - start_wr_iops[i]
 124
 125             self.assertTrue(check_limit(params['bps'], rd_bytes + wr_bytes))
 126             self.assertTrue(check_limit(params['bps_rd'], rd_bytes))
 127             self.assertTrue(check_limit(params['bps_wr'], wr_bytes))
 128             self.assertTrue(check_limit(params['iops'], rd_iops + wr_iops))
 129             self.assertTrue(check_limit(params['iops_rd'], rd_iops))
 130             self.assertTrue(check_limit(params['iops_wr'], wr_iops))
 131
 132     def test_all(self):
 133         params = {"bps": 4096,
 134                   "bps_rd": 4096,
 135                   "bps_wr": 4096,
 136                   "iops": 10,
 137                   "iops_rd": 10,
 138                   "iops_wr": 10,
 139                  }
 140         # Repeat the test with different numbers of drives
 141         for ndrives in range(1, self.max_drives + 1):
 142             # Pick each out of all possible params and test
 143             for tk in params:
 144                 limits = dict([(k, 0) for k in params])
 145                 limits[tk] = params[tk] * ndrives
 146                 self.configure_throttle(ndrives, limits)
 147                 self.do_test_throttle(ndrives, 5, limits)
 148
 149     def test_burst(self):
 150         params = {"bps": 4096,
 151                   "bps_rd": 4096,
 152                   "bps_wr": 4096,
 153                   "iops": 10,
 154                   "iops_rd": 10,
 155                   "iops_wr": 10,
 156                  }
 157         ndrives = 1
 158         # Pick each out of all possible params and test
 159         for tk in params:
 160             rate = params[tk] * ndrives
 161             burst_rate = rate * 7
 162             burst_length = 4
 163
 164             # Configure the throttling settings
 165             settings = dict([(k, 0) for k in params])
 166             settings[tk] = rate
 167             settings['%s_max' % tk] = burst_rate
 168             settings['%s_max_length' % tk] = burst_length
 169             self.configure_throttle(ndrives, settings)
 170
 171             # Wait for the bucket to empty so we can do bursts
 172             wait_ns = nsec_per_sec * burst_length * burst_rate / rate
 173             self.vm.qtest("clock_step %d" % wait_ns)
 174
 175             # Test I/O at the max burst rate
 176             limits = dict([(k, 0) for k in params])
 177             limits[tk] = burst_rate
 178             self.do_test_throttle(ndrives, burst_length, limits)
 179
 180             # Now test I/O at the normal rate
 181             limits[tk] = rate
 182             self.do_test_throttle(ndrives, 5, limits)
 183
 184 class ThrottleTestCoroutine(ThrottleTestCase):
 185     test_img = "null-co://"
 186
 187 if __name__ == '__main__':
 188     iotests.main(supported_fmts=["raw"])