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qemu-iotests: Extend iotest 093 to test bursts

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This patch adds a new test that checks that the burst settings
('iops_max', 'iops_max_length', etc.) of the throttling code work as
expected.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Alberto Garcia 2016-02-18 12:27:07 +02:00 committed by Kevin Wolf
parent f9d058852c
commit a90cade023
2 changed files with 53 additions and 16 deletions
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65
tests/qemu-iotests/093
View File

@ -3,7 +3,7 @@
# Tests for IO throttling
#
# Copyright (C) 2015 Red Hat, Inc.
# Copyright (C) 2015 Igalia, S.L.
# Copyright (C) 2015-2016 Igalia, S.L.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
@ -21,6 +21,8 @@
import iotests
nsec_per_sec = 1000000000
class ThrottleTestCase(iotests.QMPTestCase):
test_img = "null-aio://"
max_drives = 3
@ -42,16 +44,7 @@ class ThrottleTestCase(iotests.QMPTestCase):
def tearDown(self):
self.vm.shutdown()
def do_test_throttle(self, ndrives, seconds, params):
def check_limit(limit, num):
# IO throttling algorithm is discrete, allow 10% error so the test
# is more robust
return limit == 0 or \
(num < seconds * limit * 1.1 / ndrives
and num > seconds * limit * 0.9 / ndrives)
nsec_per_sec = 1000000000
def configure_throttle(self, ndrives, params):
params['group'] = 'test'
# Set the I/O throttling parameters to all drives
@ -60,13 +53,21 @@ class ThrottleTestCase(iotests.QMPTestCase):
result = self.vm.qmp("block_set_io_throttle", conv_keys=False, **params)
self.assert_qmp(result, 'return', {})
def do_test_throttle(self, ndrives, seconds, params):
def check_limit(limit, num):
# IO throttling algorithm is discrete, allow 10% error so the test
# is more robust
return limit == 0 or \
(num < seconds * limit * 1.1 / ndrives
and num > seconds * limit * 0.9 / ndrives)
# Set vm clock to a known value
ns = seconds * nsec_per_sec
self.vm.qtest("clock_step %d" % ns)
# Submit enough requests. They will drain bps_max and iops_max, but the
# rest requests won't get executed until we advance the virtual clock
# with qtest interface
# Submit enough requests so the throttling mechanism kicks
# in. The throttled requests won't be executed until we
# advance the virtual clock.
rq_size = 512
rd_nr = max(params['bps'] / rq_size / 2,
params['bps_rd'] / rq_size,
@ -142,8 +143,44 @@ class ThrottleTestCase(iotests.QMPTestCase):
for tk in params:
limits = dict([(k, 0) for k in params])
limits[tk] = params[tk] * ndrives
self.configure_throttle(ndrives, limits)
self.do_test_throttle(ndrives, 5, limits)
def test_burst(self):
params = {"bps": 4096,
"bps_rd": 4096,
"bps_wr": 4096,
"iops": 10,
"iops_rd": 10,
"iops_wr": 10,
}
ndrives = 1
# Pick each out of all possible params and test
for tk in params:
rate = params[tk] * ndrives
burst_rate = rate * 7
burst_length = 4
# Configure the throttling settings
settings = dict([(k, 0) for k in params])
settings[tk] = rate
settings['%s_max' % tk] = burst_rate
settings['%s_max_length' % tk] = burst_length
self.configure_throttle(ndrives, settings)
# Wait for the bucket to empty so we can do bursts
wait_ns = nsec_per_sec * burst_length * burst_rate / rate
self.vm.qtest("clock_step %d" % wait_ns)
# Test I/O at the max burst rate
limits = dict([(k, 0) for k in params])
limits[tk] = burst_rate
self.do_test_throttle(ndrives, burst_length, limits)
# Now test I/O at the normal rate
limits[tk] = rate
self.do_test_throttle(ndrives, 5, limits)
class ThrottleTestCoroutine(ThrottleTestCase):
test_img = "null-co://"

4
tests/qemu-iotests/093.out
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@ -1,5 +1,5 @@
..
....
----------------------------------------------------------------------
Ran 2 tests
Ran 4 tests
OK