def run_timedrift_with_migration(test, params, env):
    """
    Time drift test with migration:

    1) Log into a guest.
    2) Take a time reading from the guest and host.
    3) Migrate the guest.
    4) Take a second time reading.
    5) If the drift (in seconds) is higher than a user specified value, fail.

    @param test: KVM test object.
    @param params: Dictionary with test parameters.
    @param env: Dictionary with the test environment.
    """
    vm = env.get_vm(params["main_vm"])
    vm.verify_alive()
    timeout = int(params.get("login_timeout", 360))
    session = vm.wait_for_login(timeout=timeout)

    # Collect test parameters:
    # Command to run to get the current time
    time_command = params.get("time_command")
    # Filter which should match a string to be passed to time.strptime()
    time_filter_re = params.get("time_filter_re")
    # Time format for time.strptime()
    time_format = params.get("time_format")
    drift_threshold = float(params.get("drift_threshold", "10"))
    drift_threshold_single = float(params.get("drift_threshold_single", "3"))
    migration_iterations = int(params.get("migration_iterations", 1))

    try:
        # Get initial time
        # (ht stands for host time, gt stands for guest time)
        (ht0, gt0) = utils_test.get_time(session, time_command,
                                             time_filter_re, time_format)

        # Migrate
        for i in range(migration_iterations):
            # Get time before current iteration
            (ht0_, gt0_) = utils_test.get_time(session, time_command,
                                                   time_filter_re, time_format)
            session.close()
            # Run current iteration
            logging.info("Migrating: iteration %d of %d...",
                         (i + 1), migration_iterations)
            vm.migrate()
            # Log in
            logging.info("Logging in after migration...")
            session = vm.wait_for_login(timeout=30)
            logging.info("Logged in after migration")
            # Get time after current iteration
            (ht1_, gt1_) = utils_test.get_time(session, time_command,
                                                   time_filter_re, time_format)
            # Report iteration results
            host_delta = ht1_ - ht0_
            guest_delta = gt1_ - gt0_
            drift = abs(host_delta - guest_delta)
            logging.info("Host duration (iteration %d): %.2f",
                         (i + 1), host_delta)
            logging.info("Guest duration (iteration %d): %.2f",
                         (i + 1), guest_delta)
            logging.info("Drift at iteration %d: %.2f seconds",
                         (i + 1), drift)
            # Fail if necessary
            if drift > drift_threshold_single:
                raise error.TestFail("Time drift too large at iteration %d: "
                                     "%.2f seconds" % (i + 1, drift))

        # Get final time
        (ht1, gt1) = utils_test.get_time(session, time_command,
                                             time_filter_re, time_format)

    finally:
        if session:
            session.close()

    # Report results
    host_delta = ht1 - ht0
    guest_delta = gt1 - gt0
    drift = abs(host_delta - guest_delta)
    logging.info("Host duration (%d migrations): %.2f",
                 migration_iterations, host_delta)
    logging.info("Guest duration (%d migrations): %.2f",
                 migration_iterations, guest_delta)
    logging.info("Drift after %d migrations: %.2f seconds",
                 migration_iterations, drift)

    # Fail if necessary
    if drift > drift_threshold:
        raise error.TestFail("Time drift too large after %d migrations: "
                             "%.2f seconds" % (migration_iterations, drift))
Esempio n. 2
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def run_time_manage(test, params, env):
    """
    Time manage test:

    1) Generate stress in host.
    2) Run atleast 15 vms with "driftfix=slew" option
    3) Reboot the guest.
    4) Repeat the step 3 for all guests and check whether the guest
       responds properly(not any watchdog reported).
    5) TODO: Improve the way of checking the response and
        run some stress inside guest too.
    6) Continue the step 4 for 10 iterations and
       record the guest/host realtime, calculate drift in time for
       each iterations.
    7) Print the drift values for all sessions
    8) TODO: Validate if the drift value has to be within defined value

    @param test: KVM test object.
    @param params: Dictionary with test parameters.
    @param env: Dictionary with the test environment.
    """
    # Checking the main vm is alive
    vm = env.get_vm(params["main_vm"])
    vm.verify_alive()
    timeout = int(params.get("login_timeout", 360))
    session = vm.wait_for_login(timeout=timeout)

    # Collect test parameters
    login_timeout = float(params.get("login_timeout", 240))
    host_load_command = params.get("host_load_command")
    host_load_kill_command = params.get("host_load_kill_command")
    time_command = params.get("time_command")
    time_filter_re = params.get("time_filter_re")
    time_format = params.get("time_format")

    # Intialize the variables
    itr = 0
    num = 2
    host_load_sessions = []
    sessions = [session]
    prev_time = []
    curr_time = []
    timedrift = []
    totaldrift = []
    vmnames =["vm1"]

    # Run some load on the host
    logging.info("Starting load on host.")
    host_load_sessions.append(aexpect.run_bg(host_load_command,
                                             output_func=logging.debug,
                                             output_prefix="host load ",
                                             timeout=0.5))
    # Boot the VMs
    try:
        while num <= int(params.get("max_vms")):
            # Clone vm according to the first one
            vm_name = "vm%d" % num
            vmnames.append(vm_name)
            vm_params = vm.params.copy()
            curr_vm = vm.clone(vm_name, vm_params)
            env.register_vm(vm_name, curr_vm)
            env_process.preprocess_vm(test, vm_params, env, vm_name)
            params["vms"] += " " + vm_name

            sessions.append(curr_vm.wait_for_login(timeout=login_timeout))
            logging.info("Guest #%d booted up successfully", num)

            # Check whether all previous shell sessions are responsive
            error.context("checking responsiveness of the booted guest")
            for se in sessions:
                se.cmd(params.get("alive_test_cmd"))
            num += 1

        while itr <= int(params.get("max_itrs")):
            for vmid,se in enumerate(sessions):
                # Get the respective vm object
                vmname = "vm%d" % (vmid +1)
                vm = env.get_vm(vmname)
                # Run current iteration
                logging.info("Rebooting:vm%d iteration %d " % ((vmid + 1), itr))
                se = vm.reboot(se ,timeout=timeout)
                # Remember the current changed session
                sessions[vmid] = se
                error.context("checking responsiveness of guest")
                se.cmd(params.get("alive_test_cmd"))
                if itr == 0:
                    (ht0, gt0) = utils_test.get_time(se, time_command,
                                                   time_filter_re, time_format)
                    prev_time.append((ht0, gt0))
                else:
                    (ht1, gt1) = utils_test.get_time(se, time_command,
                                                   time_filter_re, time_format)
                    curr_time.append((ht1, gt1))
            if itr != 0:
                for i in range(int(params.get("max_vms"))):
                    hdelta = curr_time[i][0] - prev_time[i][0]
                    gdelta = curr_time[i][1] - prev_time[i][1]
                    drift = format( 100.0 * (hdelta - gdelta) / hdelta, ".2f" )
                    timedrift.append(drift)
                totaldrift.append(timedrift)
                prev_time = curr_time
                timedrift = []
                curr_time = []
            # Wait for some time before next iteration
            time.sleep(30)
            itr += 1

        logging.info("The time drift values for all VM sessions/iterations")
        logging.info("VM-Name:%s" % vmnames)
        for idx,value in enumerate(totaldrift):
            logging.info("itr-%2d:%s" % (idx+1,value))

    finally:
        for se in sessions:
            # Closing all the sessions.
            se.close()
        logging.info("killing load on host.")
        host_load_sessions.append(aexpect.run_bg(host_load_kill_command,
                                                 output_func=logging.debug,
                                                 output_prefix="host load kill",
                                                 timeout=0.5))
Esempio n. 3
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def run_timedrift_with_reboot(test, params, env):
    """
    Time drift test with reboot:

    1) Log into a guest.
    2) Take a time reading from the guest and host.
    3) Reboot the guest.
    4) Take a second time reading.
    5) If the drift (in seconds) is higher than a user specified value, fail.

    @param test: KVM test object.
    @param params: Dictionary with test parameters.
    @param env: Dictionary with the test environment.
    """
    vm = env.get_vm(params["main_vm"])
    vm.verify_alive()
    timeout = int(params.get("login_timeout", 360))
    session = vm.wait_for_login(timeout=timeout)

    # Collect test parameters:
    # Command to run to get the current time
    time_command = params.get("time_command")
    # Filter which should match a string to be passed to time.strptime()
    time_filter_re = params.get("time_filter_re")
    # Time format for time.strptime()
    time_format = params.get("time_format")
    drift_threshold = float(params.get("drift_threshold", "10"))
    drift_threshold_single = float(params.get("drift_threshold_single", "3"))
    reboot_iterations = int(params.get("reboot_iterations", 1))

    try:
        # Get initial time
        # (ht stands for host time, gt stands for guest time)
        (ht0, gt0) = utils_test.get_time(session, time_command, time_filter_re,
                                         time_format)

        # Reboot
        for i in range(reboot_iterations):
            # Get time before current iteration
            (ht0_, gt0_) = utils_test.get_time(session, time_command,
                                               time_filter_re, time_format)
            # Run current iteration
            logging.info("Rebooting: iteration %d of %d...", (i + 1),
                         reboot_iterations)
            session = vm.reboot(session)
            # Get time after current iteration
            (ht1_, gt1_) = utils_test.get_time(session, time_command,
                                               time_filter_re, time_format)
            # Report iteration results
            host_delta = ht1_ - ht0_
            guest_delta = gt1_ - gt0_
            drift = abs(host_delta - guest_delta)
            logging.info("Host duration (iteration %d): %.2f", (i + 1),
                         host_delta)
            logging.info("Guest duration (iteration %d): %.2f", (i + 1),
                         guest_delta)
            logging.info("Drift at iteration %d: %.2f seconds", (i + 1), drift)
            # Fail if necessary
            if drift > drift_threshold_single:
                raise error.TestFail("Time drift too large at iteration %d: "
                                     "%.2f seconds" % (i + 1, drift))

        # Get final time
        (ht1, gt1) = utils_test.get_time(session, time_command, time_filter_re,
                                         time_format)

    finally:
        if session:
            session.close()

    # Report results
    host_delta = ht1 - ht0
    guest_delta = gt1 - gt0
    drift = abs(host_delta - guest_delta)
    logging.info("Host duration (%d reboots): %.2f", reboot_iterations,
                 host_delta)
    logging.info("Guest duration (%d reboots): %.2f", reboot_iterations,
                 guest_delta)
    logging.info("Drift after %d reboots: %.2f seconds", reboot_iterations,
                 drift)

    # Fail if necessary
    if drift > drift_threshold:
        raise error.TestFail("Time drift too large after %d reboots: "
                             "%.2f seconds" % (reboot_iterations, drift))
Esempio n. 4
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def run_timedrift(test, params, env):
    """
    Time drift test (mainly for Windows guests):

    1) Log into a guest.
    2) Take a time reading from the guest and host.
    3) Run load on the guest and host.
    4) Take a second time reading.
    5) Stop the load and rest for a while.
    6) Take a third time reading.
    7) If the drift immediately after load is higher than a user-
    specified value (in %), fail.
    If the drift after the rest period is higher than a user-specified value,
    fail.

    @param test: KVM test object.
    @param params: Dictionary with test parameters.
    @param env: Dictionary with the test environment.
    """

    # Helper functions
    def set_cpu_affinity(pid, mask):
        """
        Set the CPU affinity of all threads of the process with PID pid.
        Do this recursively for all child processes as well.

        @param pid: The process ID.
        @param mask: The CPU affinity mask.
        @return: A dict containing the previous mask for each thread.
        """
        tids = commands.getoutput("ps -L --pid=%s -o lwp=" % pid).split()
        prev_masks = {}
        for tid in tids:
            prev_mask = commands.getoutput("taskset -p %s" % tid).split()[-1]
            prev_masks[tid] = prev_mask
            commands.getoutput("taskset -p %s %s" % (mask, tid))
        children = commands.getoutput("ps --ppid=%s -o pid=" % pid).split()
        for child in children:
            prev_masks.update(set_cpu_affinity(child, mask))
        return prev_masks

    def restore_cpu_affinity(prev_masks):
        """
        Restore the CPU affinity of several threads.

        @param prev_masks: A dict containing TIDs as keys and masks as values.
        """
        for tid, mask in prev_masks.items():
            commands.getoutput("taskset -p %s %s" % (mask, tid))

    vm = env.get_vm(params["main_vm"])
    vm.verify_alive()
    timeout = int(params.get("login_timeout", 360))
    session = vm.wait_for_login(timeout=timeout)

    # Collect test parameters:
    # Command to run to get the current time
    time_command = params.get("time_command")
    # Filter which should match a string to be passed to time.strptime()
    time_filter_re = params.get("time_filter_re")
    # Time format for time.strptime()
    time_format = params.get("time_format")
    guest_load_command = params.get("guest_load_command")
    guest_load_stop_command = params.get("guest_load_stop_command")
    host_load_command = params.get("host_load_command")
    guest_load_instances = int(params.get("guest_load_instances", "1"))
    host_load_instances = int(params.get("host_load_instances", "0"))
    # CPU affinity mask for taskset
    cpu_mask = params.get("cpu_mask", "0xFF")
    load_duration = float(params.get("load_duration", "30"))
    rest_duration = float(params.get("rest_duration", "10"))
    drift_threshold = float(params.get("drift_threshold", "200"))
    drift_threshold_after_rest = float(
        params.get("drift_threshold_after_rest", "200"))

    guest_load_sessions = []
    host_load_sessions = []

    try:
        # Set the VM's CPU affinity
        prev_affinity = set_cpu_affinity(vm.get_shell_pid(), cpu_mask)

        try:
            # Open shell sessions with the guest
            logging.info("Starting load on guest...")
            for i in range(guest_load_instances):
                load_session = vm.login()
                # Set output func to None to stop it from being called so we
                # can change the callback function and the parameters it takes
                # with no problems
                load_session.set_output_func(None)
                load_session.set_output_params(())
                load_session.set_output_prefix("(guest load %d) " % i)
                load_session.set_output_func(logging.debug)
                guest_load_sessions.append(load_session)

            # Get time before load
            # (ht stands for host time, gt stands for guest time)
            (ht0, gt0) = utils_test.get_time(session, time_command,
                                             time_filter_re, time_format)

            # Run some load on the guest
            for load_session in guest_load_sessions:
                load_session.sendline(guest_load_command)

            # Run some load on the host
            logging.info("Starting load on host...")
            for i in range(host_load_instances):
                host_load_sessions.append(
                    aexpect.run_bg(host_load_command,
                                   output_func=logging.debug,
                                   output_prefix="(host load %d) " % i,
                                   timeout=0.5))
                # Set the CPU affinity of the load process
                pid = host_load_sessions[-1].get_pid()
                set_cpu_affinity(pid, cpu_mask)

            # Sleep for a while (during load)
            logging.info("Sleeping for %s seconds...", load_duration)
            time.sleep(load_duration)

            # Get time delta after load
            (ht1, gt1) = utils_test.get_time(session, time_command,
                                             time_filter_re, time_format)

            # Report results
            host_delta = ht1 - ht0
            guest_delta = gt1 - gt0
            drift = 100.0 * (host_delta - guest_delta) / host_delta
            logging.info("Host duration: %.2f", host_delta)
            logging.info("Guest duration: %.2f", guest_delta)
            logging.info("Drift: %.2f%%", drift)

        finally:
            logging.info("Cleaning up...")
            # Restore the VM's CPU affinity
            restore_cpu_affinity(prev_affinity)
            # Stop the guest load
            if guest_load_stop_command:
                session.cmd_output(guest_load_stop_command)
            # Close all load shell sessions
            for load_session in guest_load_sessions:
                load_session.close()
            for load_session in host_load_sessions:
                load_session.close()

        # Sleep again (rest)
        logging.info("Sleeping for %s seconds...", rest_duration)
        time.sleep(rest_duration)

        # Get time after rest
        (ht2, gt2) = utils_test.get_time(session, time_command, time_filter_re,
                                         time_format)

    finally:
        session.close()

    # Report results
    host_delta_total = ht2 - ht0
    guest_delta_total = gt2 - gt0
    drift_total = 100.0 * (host_delta_total - guest_delta_total) / host_delta
    logging.info("Total host duration including rest: %.2f", host_delta_total)
    logging.info("Total guest duration including rest: %.2f",
                 guest_delta_total)
    logging.info("Total drift after rest: %.2f%%", drift_total)

    # Fail the test if necessary
    if abs(drift) > drift_threshold:
        raise error.TestFail("Time drift too large: %.2f%%" % drift)
    if abs(drift_total) > drift_threshold_after_rest:
        raise error.TestFail("Time drift too large after rest period: %.2f%%" %
                             drift_total)
Esempio n. 5
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def run_timedrift_with_stop(test, params, env):
    """
    Time drift test with stop/continue the guest:

    1) Log into a guest.
    2) Take a time reading from the guest and host.
    3) Stop the running of the guest
    4) Sleep for a while
    5) Continue the guest running
    6) Take a second time reading.
    7) If the drift (in seconds) is higher than a user specified value, fail.

    @param test: KVM test object.
    @param params: Dictionary with test parameters.
    @param env: Dictionary with the test environment.
    """
    login_timeout = int(params.get("login_timeout", 360))
    sleep_time = int(params.get("sleep_time", 30))
    vm = env.get_vm(params["main_vm"])
    vm.verify_alive()
    session = vm.wait_for_login(timeout=login_timeout)

    # Collect test parameters:
    # Command to run to get the current time
    time_command = params.get("time_command")
    # Filter which should match a string to be passed to time.strptime()
    time_filter_re = params.get("time_filter_re")
    # Time format for time.strptime()
    time_format = params.get("time_format")
    drift_threshold = float(params.get("drift_threshold", "10"))
    drift_threshold_single = float(params.get("drift_threshold_single", "3"))
    stop_iterations = int(params.get("stop_iterations", 1))
    stop_time = int(params.get("stop_time", 60))

    try:
        # Get initial time
        # (ht stands for host time, gt stands for guest time)
        (ht0, gt0) = utils_test.get_time(session, time_command,
                                             time_filter_re, time_format)

        # Stop the guest
        for i in range(stop_iterations):
            # Get time before current iteration
            (ht0_, gt0_) = utils_test.get_time(session, time_command,
                                                   time_filter_re, time_format)
            # Run current iteration
            logging.info("Stop %s second: iteration %d of %d...",
                         stop_time, (i + 1), stop_iterations)

            vm.pause()
            time.sleep(stop_time)
            vm.resume()

            # Sleep for a while to wait the interrupt to be reinjected
            logging.info("Waiting for the interrupt to be reinjected ...")
            time.sleep(sleep_time)

            # Get time after current iteration
            (ht1_, gt1_) = utils_test.get_time(session, time_command,
                                                   time_filter_re, time_format)
            # Report iteration results
            host_delta = ht1_ - ht0_
            guest_delta = gt1_ - gt0_
            drift = abs(host_delta - guest_delta)
            logging.info("Host duration (iteration %d): %.2f",
                         (i + 1), host_delta)
            logging.info("Guest duration (iteration %d): %.2f",
                         (i + 1), guest_delta)
            logging.info("Drift at iteration %d: %.2f seconds",
                         (i + 1), drift)
            # Fail if necessary
            if drift > drift_threshold_single:
                raise error.TestFail("Time drift too large at iteration %d: "
                                     "%.2f seconds" % (i + 1, drift))

        # Get final time
        (ht1, gt1) = utils_test.get_time(session, time_command,
                                             time_filter_re, time_format)

    finally:
        if session:
            session.close()

    # Report results
    host_delta = ht1 - ht0
    guest_delta = gt1 - gt0
    drift = abs(host_delta - guest_delta)
    logging.info("Host duration (%d stops): %.2f",
                 stop_iterations, host_delta)
    logging.info("Guest duration (%d stops): %.2f",
                 stop_iterations, guest_delta)
    logging.info("Drift after %d stops: %.2f seconds",
                 stop_iterations, drift)

    # Fail if necessary
    if drift > drift_threshold:
        raise error.TestFail("Time drift too large after %d stops: "
                             "%.2f seconds" % (stop_iterations, drift))
Esempio n. 6
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def run_time_manage(test, params, env):
    """
    Time manage test:

    1) Generate stress in host.
    2) Run atleast 15 vms with "driftfix=slew" option
    3) Reboot the guest.
    4) Repeat the step 3 for all guests and check whether the guest
       responds properly(not any watchdog reported).
    5) TODO: Improve the way of checking the response and
        run some stress inside guest too.
    6) Continue the step 4 for 10 iterations and
       record the guest/host realtime, calculate drift in time for
       each iterations.
    7) Print the drift values for all sessions
    8) TODO: Validate if the drift value has to be within defined value

    @param test: KVM test object.
    @param params: Dictionary with test parameters.
    @param env: Dictionary with the test environment.
    """
    # Checking the main vm is alive
    vm = env.get_vm(params["main_vm"])
    vm.verify_alive()
    timeout = int(params.get("login_timeout", 360))
    session = vm.wait_for_login(timeout=timeout)

    # Collect test parameters
    login_timeout = float(params.get("login_timeout", 240))
    host_load_command = params.get("host_load_command")
    host_load_kill_command = params.get("host_load_kill_command")
    time_command = params.get("time_command")
    time_filter_re = params.get("time_filter_re")
    time_format = params.get("time_format")

    # Intialize the variables
    itr = 0
    num = 2
    host_load_sessions = []
    sessions = [session]
    prev_time = []
    curr_time = []
    timedrift = []
    totaldrift = []
    vmnames = ["vm1"]

    # Run some load on the host
    logging.info("Starting load on host.")
    host_load_sessions.append(
        aexpect.run_bg(host_load_command,
                       output_func=logging.debug,
                       output_prefix="host load ",
                       timeout=0.5))
    # Boot the VMs
    try:
        while num <= int(params.get("max_vms")):
            # Clone vm according to the first one
            vm_name = "vm%d" % num
            vmnames.append(vm_name)
            vm_params = vm.params.copy()
            curr_vm = vm.clone(vm_name, vm_params)
            env.register_vm(vm_name, curr_vm)
            env_process.preprocess_vm(test, vm_params, env, vm_name)
            params["vms"] += " " + vm_name

            sessions.append(curr_vm.wait_for_login(timeout=login_timeout))
            logging.info("Guest #%d booted up successfully", num)

            # Check whether all previous shell sessions are responsive
            error.context("checking responsiveness of the booted guest")
            for se in sessions:
                se.cmd(params.get("alive_test_cmd"))
            num += 1

        while itr <= int(params.get("max_itrs")):
            for vmid, se in enumerate(sessions):
                # Get the respective vm object
                vmname = "vm%d" % (vmid + 1)
                vm = env.get_vm(vmname)
                # Run current iteration
                logging.info("Rebooting:vm%d iteration %d " %
                             ((vmid + 1), itr))
                se = vm.reboot(se, timeout=timeout)
                # Remember the current changed session
                sessions[vmid] = se
                error.context("checking responsiveness of guest")
                se.cmd(params.get("alive_test_cmd"))
                if itr == 0:
                    (ht0, gt0) = utils_test.get_time(se, time_command,
                                                     time_filter_re,
                                                     time_format)
                    prev_time.append((ht0, gt0))
                else:
                    (ht1, gt1) = utils_test.get_time(se, time_command,
                                                     time_filter_re,
                                                     time_format)
                    curr_time.append((ht1, gt1))
            if itr != 0:
                for i in range(int(params.get("max_vms"))):
                    hdelta = curr_time[i][0] - prev_time[i][0]
                    gdelta = curr_time[i][1] - prev_time[i][1]
                    drift = format(100.0 * (hdelta - gdelta) / hdelta, ".2f")
                    timedrift.append(drift)
                totaldrift.append(timedrift)
                prev_time = curr_time
                timedrift = []
                curr_time = []
            # Wait for some time before next iteration
            time.sleep(30)
            itr += 1

        logging.info("The time drift values for all VM sessions/iterations")
        logging.info("VM-Name:%s" % vmnames)
        for idx, value in enumerate(totaldrift):
            logging.info("itr-%2d:%s" % (idx + 1, value))

    finally:
        for se in sessions:
            # Closing all the sessions.
            se.close()
        logging.info("killing load on host.")
        host_load_sessions.append(
            aexpect.run_bg(host_load_kill_command,
                           output_func=logging.debug,
                           output_prefix="host load kill",
                           timeout=0.5))
Esempio n. 7
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def run_timedrift(test, params, env):
    """
    Time drift test (mainly for Windows guests):

    1) Log into a guest.
    2) Take a time reading from the guest and host.
    3) Run load on the guest and host.
    4) Take a second time reading.
    5) Stop the load and rest for a while.
    6) Take a third time reading.
    7) If the drift immediately after load is higher than a user-
    specified value (in %), fail.
    If the drift after the rest period is higher than a user-specified value,
    fail.

    @param test: KVM test object.
    @param params: Dictionary with test parameters.
    @param env: Dictionary with the test environment.
    """
    # Helper functions
    def set_cpu_affinity(pid, mask):
        """
        Set the CPU affinity of all threads of the process with PID pid.
        Do this recursively for all child processes as well.

        @param pid: The process ID.
        @param mask: The CPU affinity mask.
        @return: A dict containing the previous mask for each thread.
        """
        tids = commands.getoutput("ps -L --pid=%s -o lwp=" % pid).split()
        prev_masks = {}
        for tid in tids:
            prev_mask = commands.getoutput("taskset -p %s" % tid).split()[-1]
            prev_masks[tid] = prev_mask
            commands.getoutput("taskset -p %s %s" % (mask, tid))
        children = commands.getoutput("ps --ppid=%s -o pid=" % pid).split()
        for child in children:
            prev_masks.update(set_cpu_affinity(child, mask))
        return prev_masks

    def restore_cpu_affinity(prev_masks):
        """
        Restore the CPU affinity of several threads.

        @param prev_masks: A dict containing TIDs as keys and masks as values.
        """
        for tid, mask in prev_masks.items():
            commands.getoutput("taskset -p %s %s" % (mask, tid))

    vm = env.get_vm(params["main_vm"])
    vm.verify_alive()
    timeout = int(params.get("login_timeout", 360))
    session = vm.wait_for_login(timeout=timeout)

    # Collect test parameters:
    # Command to run to get the current time
    time_command = params.get("time_command")
    # Filter which should match a string to be passed to time.strptime()
    time_filter_re = params.get("time_filter_re")
    # Time format for time.strptime()
    time_format = params.get("time_format")
    guest_load_command = params.get("guest_load_command")
    guest_load_stop_command = params.get("guest_load_stop_command")
    host_load_command = params.get("host_load_command")
    guest_load_instances = int(params.get("guest_load_instances", "1"))
    host_load_instances = int(params.get("host_load_instances", "0"))
    # CPU affinity mask for taskset
    cpu_mask = params.get("cpu_mask", "0xFF")
    load_duration = float(params.get("load_duration", "30"))
    rest_duration = float(params.get("rest_duration", "10"))
    drift_threshold = float(params.get("drift_threshold", "200"))
    drift_threshold_after_rest = float(params.get("drift_threshold_after_rest", "200"))

    guest_load_sessions = []
    host_load_sessions = []

    try:
        # Set the VM's CPU affinity
        prev_affinity = set_cpu_affinity(vm.get_shell_pid(), cpu_mask)

        try:
            # Open shell sessions with the guest
            logging.info("Starting load on guest...")
            for i in range(guest_load_instances):
                load_session = vm.login()
                # Set output func to None to stop it from being called so we
                # can change the callback function and the parameters it takes
                # with no problems
                load_session.set_output_func(None)
                load_session.set_output_params(())
                load_session.set_output_prefix("(guest load %d) " % i)
                load_session.set_output_func(logging.debug)
                guest_load_sessions.append(load_session)

            # Get time before load
            # (ht stands for host time, gt stands for guest time)
            (ht0, gt0) = utils_test.get_time(session, time_command, time_filter_re, time_format)

            # Run some load on the guest
            for load_session in guest_load_sessions:
                load_session.sendline(guest_load_command)

            # Run some load on the host
            logging.info("Starting load on host...")
            for i in range(host_load_instances):
                host_load_sessions.append(
                    aexpect.run_bg(
                        host_load_command, output_func=logging.debug, output_prefix="(host load %d) " % i, timeout=0.5
                    )
                )
                # Set the CPU affinity of the load process
                pid = host_load_sessions[-1].get_pid()
                set_cpu_affinity(pid, cpu_mask)

            # Sleep for a while (during load)
            logging.info("Sleeping for %s seconds...", load_duration)
            time.sleep(load_duration)

            # Get time delta after load
            (ht1, gt1) = utils_test.get_time(session, time_command, time_filter_re, time_format)

            # Report results
            host_delta = ht1 - ht0
            guest_delta = gt1 - gt0
            drift = 100.0 * (host_delta - guest_delta) / host_delta
            logging.info("Host duration: %.2f", host_delta)
            logging.info("Guest duration: %.2f", guest_delta)
            logging.info("Drift: %.2f%%", drift)

        finally:
            logging.info("Cleaning up...")
            # Restore the VM's CPU affinity
            restore_cpu_affinity(prev_affinity)
            # Stop the guest load
            if guest_load_stop_command:
                session.cmd_output(guest_load_stop_command)
            # Close all load shell sessions
            for load_session in guest_load_sessions:
                load_session.close()
            for load_session in host_load_sessions:
                load_session.close()

        # Sleep again (rest)
        logging.info("Sleeping for %s seconds...", rest_duration)
        time.sleep(rest_duration)

        # Get time after rest
        (ht2, gt2) = utils_test.get_time(session, time_command, time_filter_re, time_format)

    finally:
        session.close()

    # Report results
    host_delta_total = ht2 - ht0
    guest_delta_total = gt2 - gt0
    drift_total = 100.0 * (host_delta_total - guest_delta_total) / host_delta
    logging.info("Total host duration including rest: %.2f", host_delta_total)
    logging.info("Total guest duration including rest: %.2f", guest_delta_total)
    logging.info("Total drift after rest: %.2f%%", drift_total)

    # Fail the test if necessary
    if abs(drift) > drift_threshold:
        raise error.TestFail("Time drift too large: %.2f%%" % drift)
    if abs(drift_total) > drift_threshold_after_rest:
        raise error.TestFail("Time drift too large after rest period: %.2f%%" % drift_total)