Re: [RFC PATCH] tests/avocado: re-factor igb test to avoid timeouts

[Alex Bennée]

Akihiko Odaki <akihiko.odaki@daynix.com> writes:

> On 2023/03/22 19:04, Alex Bennée wrote:
>> Akihiko Odaki <akihiko.odaki@daynix.com> writes:
>> 
>>> On 2023/03/22 3:17, Alex Bennée wrote:
>>>> The core of the test was utilising "ethtool -t eth1 offline" to run
>>>> through a test sequence. For reasons unknown the test hangs under some
>>>> configurations of the build on centos8-stream. Fundamentally running
>>>> the old fedora-31 cloud-init is just too much for something that is
>>>> directed at testing one device. So we:
>>>>     - replace fedora with a custom kernel + buildroot rootfs
>>>>     - rename the test from IGB to NetDevEthtool
>>>>     - re-factor the common code, add (currently skipped) tests for other
>>>>        devices which support ethtool
>>>>     - remove the KVM limitation as its fast enough to run in KVM or TCG
>>>
>>> I tried this but it seems the rootfs is corrupted:
>>> 2023-03-22 13:53:06,728 __init__         L0153 DEBUG| EXT4-fs (sda):
>>> INFO: recovery required on readonly filesystem
>>> 2023-03-22 13:53:06,728 __init__         L0153 DEBUG| EXT4-fs (sda):
>>> write access will be enabled during recovery
>>> (snip)
>>> 2023-03-22 13:54:24,534 __init__         L0153 DEBUG| EXT4-fs (sda):
>>> I/O error while writing superblock
>>> 2023-03-22 13:54:24,535 __init__         L0153 DEBUG| EXT4-fs (sda):
>>> error loading journal
>>> 2023-03-22 13:54:24,542 __init__         L0153 DEBUG| VFS: Cannot open
>>> root device "sda" or unknown-block(8,0): error -5
>> That's weird. I'm not seeing it when running here. However I can
>> regenerate the whole thing and re-upload. Are there any other network
>> tools worth adding?
>
> Only ethtool is needed for testing Intel NICs.
>
>> 
>>> I have a few more comments:
>>>
>>> - It may be possible to use microvm to trim it down further.
>> Does microvm have PCI now? Most of the saving comes down to having a
>> much lighter rootfs than the full cloud init of fedora. I think there is
>> only really a syslogd and a klogd running at the start.
>
> microvm supports PCIe. You can enable it by specifying e.g., -M
> microvm,pcie=on
>
>> 
>>> - I'm worried that having a rootfs for a single test is too costly to
>>>    maintain. If you just want to avoid cloud-init, you can just
>>>   specify:
>>> init=/bin/sh
>> Not really too bad. Buildroot makes it pretty easy. The config can
>> be
>> found here:
>>    https://fileserver.linaro.org/s/Lk8z7kN3s3ds7kd
>
> Buildroot indeed automates everything to build rootfs, but it still
> takes lots of time to build because it needs to build everything. It
> also fetches sources from the origins of the packages if I understand
> it correctly, and I'm worried that may harm the reproducibility of the
> builds.
>
> These problems are not present with Fedora: you can add or replace a
> particular component with a package (in this case ethtool is added),
> and Fedora mirrors everything to build the binary.

It's certainly preferable to lean on the distros and their
infrastructure although:

  - Fedora is a poor choice given the support lifetime
  - The various "full-fat" distros we run avocado tests for seem to be
    very bloated (esp compared to my local Debian setup which boots very
    quickly)
  - It's hard to argue with the time saving and stability improvements,
    especially as we are limited on CI time these days

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro