The XML we use is:
<clock offset="utc">
<timer name="rtc" tickpolicy="catchup"/>
<timer name="pit" tickpolicy="delay"/>
<timer name="hpet" present="no"/>
</clock>
Which translates to the qemu commands:
-no-hpet -no-kvm-pit-reinjection -rtc driftfix=slew
The latter two bits are already used by openstack and gnome boxes by
default.
On RHEL hpet is compiled out so -no-hpet is the default,
but not everywhere else. Though recently the RH guys confirmed that
for regular usage it should be turned off because a) qemu support
is not that good, b) most users don't need it anyways c) it has
a performance penalty.
This default can be overridden from a virt-install command like
--clock rtc_tickpolicy=delay
When Guest() sees that a timer has already been defined, it won't
set the new defaults, and that setting above is the old implied
default rtc setting.
It was required a long long time ago, before qemu supported -drive
and possibly ancient xen. Nowadays it should be pointless, and contributes
to some issues like bz 905439
This is where performance issues hit the most. This changes the
RHEL default to remove cache=None for all file volumes. If anyone
cares they can speak up, but it seems an overly unnecessary deviation
from upstream qemu.
The patches to drop /dev/loop0 meant get_blkdisk was inaccurate and
we weren't testing many things that were intended. Use a block disk
from the test driver.
The commit efab27afbf02743a3a2582e9a111eb1b7d985b26 in libvirt uses
/dev/%s for logical pools, change the tests to accommodate it.
(crobinso: additional fix to work with older libvirt)
We separate all the provisioning bits to diskbackend.py. VirtualDisk
users now need to explicitly opt in to storage creation by using
set_create_storage().
validation is no longer done automatically, users must call the
validation() command.
__init__ drops all extra parameters.
This will eventually get us to a point where we can unify the manual
XML building and XML parsing machinery, and get consistent validation
behavior between devices.
Cole Robinson