src/ceph/qa/tasks/cephfs/test_readahead.py

   1 import logging
   2 from tasks.cephfs.fuse_mount import FuseMount
   3 from tasks.cephfs.cephfs_test_case import CephFSTestCase
   4
   5 log = logging.getLogger(__name__)
   6
   7
   8 class TestReadahead(CephFSTestCase):
   9     def test_flush(self):
  10         if not isinstance(self.mount_a, FuseMount):
  11             self.skipTest("FUSE needed for measuring op counts")
  12
  13         # Create 32MB file
  14         self.mount_a.run_shell(["dd", "if=/dev/urandom", "of=foo", "bs=1M", "count=32"])
  15
  16         # Unmount and remount the client to flush cache
  17         self.mount_a.umount_wait()
  18         self.mount_a.mount()
  19         self.mount_a.wait_until_mounted()
  20
  21         initial_op_r = self.mount_a.admin_socket(['perf', 'dump', 'objecter'])['objecter']['op_r']
  22         self.mount_a.run_shell(["dd", "if=foo", "of=/dev/null", "bs=128k", "count=32"])
  23         op_r = self.mount_a.admin_socket(['perf', 'dump', 'objecter'])['objecter']['op_r']
  24         assert op_r >= initial_op_r
  25         op_r -= initial_op_r
  26         log.info("read operations: {0}".format(op_r))
  27
  28         # with exponentially increasing readahead, we should see fewer than 10 operations
  29         # but this test simply checks if the client is doing a remote read for each local read
  30         if op_r >= 32:
  31             raise RuntimeError("readahead not working")