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Re: [Qemu-devel] [PATCH v6 5/5] qemu-iotests: Add 093 for IO throttling
From: |
Fam Zheng |
Subject: |
Re: [Qemu-devel] [PATCH v6 5/5] qemu-iotests: Add 093 for IO throttling |
Date: |
Thu, 29 Jan 2015 08:53:07 +0800 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Wed, 01/28 11:22, Max Reitz wrote:
> On 2015-01-27 at 21:28, Fam Zheng wrote:
> >This case utilizes qemu-io command "aio_{read,write} -q" to verify the
> >effectiveness of IO throttling options.
> >
> >It's implemented by driving the vm timer from qtest protocol, so the
> >throttling timers are signaled with determinied time duration. Then we
> >verify the completed IO requests are within 10% error of bps and iops
> >limits.
> >
> >"null" protocol is used as the disk backend so that no actual disk IO is
> >performed on host, this will make the blockstats much more
> >deterministic. Both "null-aio" and "null-co" are covered, which is also
> >a simple cross validation test for the driver code.
> >
> >Signed-off-by: Fam Zheng <address@hidden>
> >---
> > tests/qemu-iotests/093 | 120
> > +++++++++++++++++++++++++++++++++++++++++++++
> > tests/qemu-iotests/093.out | 5 ++
> > tests/qemu-iotests/group | 1 +
> > 3 files changed, 126 insertions(+)
> > create mode 100755 tests/qemu-iotests/093
> > create mode 100644 tests/qemu-iotests/093.out
> >
> >diff --git a/tests/qemu-iotests/093 b/tests/qemu-iotests/093
> >new file mode 100755
> >index 0000000..2866536
> >--- /dev/null
> >+++ b/tests/qemu-iotests/093
> >@@ -0,0 +1,120 @@
> >+#!/usr/bin/env python
> >+#
> >+# Tests for IO throttling
> >+#
> >+# Copyright (C) 2015 Red Hat, Inc.
> >+#
> >+# 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
> >+# the Free Software Foundation; either version 2 of the License, or
> >+# (at your option) any later version.
> >+#
> >+# This program is distributed in the hope that it will be useful,
> >+# but WITHOUT ANY WARRANTY; without even the implied warranty of
> >+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> >+# GNU General Public License for more details.
> >+#
> >+# You should have received a copy of the GNU General Public License
> >+# along with this program. If not, see <http://www.gnu.org/licenses/>.
> >+#
> >+
> >+import iotests
> >+
> >+class ThrottleTestCase(iotests.QMPTestCase):
> >+ test_img = "null-aio://"
> >+
> >+ def blockstats(self, device):
> >+ result = self.vm.qmp("query-blockstats")
> >+ for r in result['return']:
> >+ if r['device'] == device:
> >+ stat = r['stats']
> >+ return stat['rd_bytes'], stat['rd_operations'],
> >stat['wr_bytes'], stat['wr_operations']
> >+ raise Exception("Device not found for blockstats: %s" % device)
> >+
> >+ def setUp(self):
> >+ self.vm = iotests.VM().add_drive(self.test_img)
> >+ self.vm.launch()
> >+
> >+ def tearDown(self):
> >+ self.vm.shutdown()
> >+
> >+ def do_test_throttle(self, 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
> >+ and num > seconds * limit * 0.9)
> >+
> >+ nsec_per_sec = 1000000000
> >+
> >+ params['device'] = 'drive0'
> >+
> >+ result = self.vm.qmp("block_set_io_throttle", conv_keys=False,
> >**params)
> >+ self.assert_qmp(result, 'return', {})
> >+
> >+ # 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
> >+ rq_size = 512
> >+ rd_nr = max(params['bps'] / rq_size / 2,
> >+ params['bps_rd'] / rq_size,
> >+ params['iops'] / 2,
> >+ params['iops_rd']) + \
> >+ params['bps_max'] / rq_size / 2 + \
> >+ params['iops_max']
>
> I guess the divisions by two are because those values represent read and
> write operations combined. Shouldn't iops_max be divided by two, too, then?
>
> >+ rd_nr *= seconds * 2
> >+ wr_nr = max(params['bps'] / rq_size / 2,
> >+ params['bps_wr'] / rq_size,
> >+ params['iops'] / 2,
> >+ params['iops_wr']) + \
> >+ params['bps_max'] / rq_size / 2 + \
> >+ params['iops_max']
> >+ wr_nr *= seconds * 2
> >+ for i in range(rd_nr):
> >+ self.vm.hmp_qemu_io("drive0", "aio_read %d %d" % (i * rq_size,
> >rq_size))
> >+ for i in range(wr_nr):
> >+ self.vm.hmp_qemu_io("drive0", "aio_write %d %d" % (i * rq_size,
> >rq_size))
> >+
> >+ start_rd_bytes, start_rd_iops, start_wr_bytes, start_wr_iops =
> >self.blockstats('drive0')
> >+
> >+ self.vm.qtest("clock_step %d" % ns)
> >+ end_rd_bytes, end_rd_iops, end_wr_bytes, end_wr_iops =
> >self.blockstats('drive0')
> >+
> >+ rd_bytes = end_rd_bytes - start_rd_bytes
> >+ rd_iops = end_rd_iops - start_rd_iops
> >+ wr_bytes = end_wr_bytes - start_wr_bytes
> >+ wr_iops = end_wr_iops - start_wr_iops
> >+
> >+ self.assertTrue(check_limit(params['bps'], rd_bytes + wr_bytes))
> >+ self.assertTrue(check_limit(params['bps_rd'], rd_bytes))
> >+ self.assertTrue(check_limit(params['bps_wr'], wr_bytes))
> >+ self.assertTrue(check_limit(params['iops'], rd_iops + wr_iops))
> >+ self.assertTrue(check_limit(params['iops_rd'], rd_iops))
> >+ self.assertTrue(check_limit(params['iops_wr'], wr_iops))
>
> Hm, you're not checking bps_max and iops_max here. Should you be?
I never really liked these two parameters, but now that you asked, probably
yes (to this question and above). :)
Fam
>
> Apart from these two (minor) things: Works for me! :-)
>
> Max
>
> >+
> >+ def test_all(self):
> >+ params = {"bps": 4096,
> >+ "bps_rd": 4096,
> >+ "bps_wr": 4096,
> >+ "bps_max": 4096,
> >+ "iops": 10,
> >+ "iops_rd": 10,
> >+ "iops_wr": 10,
> >+ "iops_max": 10,
> >+ }
> >+ # Pick each out of all possible params and test
> >+ for tk in params:
> >+ limits = dict([(k, 0) for k in params])
> >+ limits[tk] = params[tk]
> >+ self.do_test_throttle(5, limits)
> >+
> >+class ThrottleTestCoroutine(ThrottleTestCase):
> >+ test_img = "null-co://"
> >+
> >+if __name__ == '__main__':
> >+ iotests.main(supported_fmts=["raw"])
> >diff --git a/tests/qemu-iotests/093.out b/tests/qemu-iotests/093.out
> >new file mode 100644
> >index 0000000..fbc63e6
> >--- /dev/null
> >+++ b/tests/qemu-iotests/093.out
> >@@ -0,0 +1,5 @@
> >+..
> >+----------------------------------------------------------------------
> >+Ran 2 tests
> >+
> >+OK
> >diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
> >index f8bf354..0272c9a 100644
> >--- a/tests/qemu-iotests/group
> >+++ b/tests/qemu-iotests/group
> >@@ -99,6 +99,7 @@
> > 090 rw auto quick
> > 091 rw auto
> > 092 rw auto quick
> >+093 auto
> > 095 rw auto quick
> > 097 rw auto backing
> > 098 rw auto backing quick
>
- [Qemu-devel] [PATCH v6 0/5] block: Add a qemu-iotests case for IO throttling, Fam Zheng, 2015/01/27
- [Qemu-devel] [PATCH v6 2/5] qtest: Add scripts/qtest.py, Fam Zheng, 2015/01/27
- [Qemu-devel] [PATCH v6 1/5] qemu-io: Account IO by aio_read and aio_write, Fam Zheng, 2015/01/27
- [Qemu-devel] [PATCH v6 4/5] qemu-iotests: Allow caller to disable underscore convertion for qmp, Fam Zheng, 2015/01/27
- [Qemu-devel] [PATCH v6 3/5] qemu-iotests: Add VM method qtest() to iotests.py, Fam Zheng, 2015/01/27
- [Qemu-devel] [PATCH v6 5/5] qemu-iotests: Add 093 for IO throttling, Fam Zheng, 2015/01/27