A throttle group can have several members, and each one of them can
have several pending requests in the queue.
The requests are processed in a round-robin fashion, so the algorithm
decides the drive that is going to run the next request and sets a
timer in it. Once the timer fires and the throttled request is run
then the next drive from the group is selected and a new timer is set.
If the user tried to remove a drive from a group and that drive had a
timer set then the code was not taking care of setting up a new timer
in one of the remaining members of the group, freezing their I/O.
This problem was fixed in 6fccbb475b,
and this patch adds a new test case that reproduces this exact
scenario.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This test hotplugs a CD drive to a VM and checks that I/O limits can
be set only when the drive has media inserted and that they are kept
when the media is replaced.
This also tests the removal of a device with valid I/O limits set but
no media inserted. This involves deleting and disabling the limits
of a BlockBackend without BlockDriverState, a scenario that has been
crashing until the fixes from the last couple of patches.
[Python PEP8 fixup: "Don't use spaces are the = sign when used to
indicate a keyword argument or a default parameter value"
--Stefan]
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 071eb397118ed207c5a7f01d58766e415ee18d6a.1510339534.git.berto@igalia.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
iotest 093 contains a test that creates a throttling group with
several drives and performs I/O in all of them. This patch adds a new
test that creates a similar setup but only performs I/O in one of the
drives at the same time.
This is useful to test that the round robin algorithm is behaving
properly in these scenarios, and is specifically written using the
regression introduced in 27ccdd5259 as an example.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Throttling groups are named using the 'group' parameter of the
block_set_io_throttle command and the throttling.group command-line
option. If that parameter is unspecified the groups get the name of
the block device.
This patch adds a new test to check the naming of throttling groups.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Message-id: d87d02823a6b91609509d8bb18e2f5dbd9a6102c.1467986342.git.berto@igalia.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
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 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 <famz@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 1422586186-9925-6-git-send-email-famz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
