Description
Currently, the unittests in the vmm
package have to be run sequentially due to reliance on global state in some virtio device tests. More specifically, various tests in the vsock
and rng
modules use a global METRICS
object (see also #2899). This design using a global METRICS object is fine for production, because a VMM can have at most one vsock and rng device each, however multiple unit tests running in parallel can create multiple device objects, which then simultaneously update the global metrics. Since our tests contain assertions on the value of the metrics to validate functionality, this causes spurious failures.
We can fix this by moving the vsock and rng device to a "per device metrics" model, as already adopted by net and block devices (see for example #4145).
As part of this issue, 3 things will need to be done
- Update the vsock device to use a "per device metrics" modelUpdate the rng device to use a "per device metrics" modelFix the
test_tap_name
test to no longer use a hardcoded value oftap0
(if multiple tests run in parallel and create tap devices, it is no longer guaranteed that the tap device created in this test will be called "tap0", it could be "tap1" or "tap43". Thus we probably just want some sort of regex match on the tap device name).
These can all be addressed in individual PRs, or all in one, depending on how much of a task you want to tackle :)
Activity
[-]Allow Running `vmm` unittests in parallel[/-][+]Allow Running `vmm` Unittests in Parallel[/+]jackabald commentedon Aug 2, 2024
@roypat
I can try to look at this. Will send PR if I get anywhere.
Thanks!
gjkeller commentedon Apr 10, 2025
@jackabald
CC @roypat
Are you still planning on working on this issue? If not, would I be able to take this on? Thank you!
bchalios commentedon Apr 16, 2025
Hey @gjkeller. There isn't any progress here. Feel free to contribute to it, if you want.
bstrong04 commentedon May 7, 2025
Submitted a hopeful fix to this by working with @gjkeller. If there's any changes needed to be made or if I went in the wrong direction please let me know.