As a side effect of  bug 757147 , more people are interested in the fact that the chromiumos-sdk builder takes a very long time to run. Recent runs are roughly 16 hours [1]. It's probably worth improving this, as people might often want to make sure things don't break here (the SDK builder tests from source builds, which surface different problems than the CQ currently does).

It's possibly worth considering whether it's feasible to run an SDK builder on the CQ as well, to help limit damage like  bug 757147 , where it took days to track down the CL that broke the SDK builder.

Low-hanging fruit: we run the SDKTest stage with sequential builds of a few boards:

chromite/cbuildbot/stages/sdk_stages.py:

    # Build all the boards with the new sdk.
    for board in self._boards:
      logging.PrintBuildbotStepText(board)
      commands.SetupBoard(self._build_root, board, usepkg=True,
                          chroot_upgrade=False,
                          extra_env=self._portage_extra_env,
                          chroot_args=new_chroot_args)
      commands.Build(self._build_root, board, build_autotest=True,
                     usepkg=False, chrome_binhost_only=False,
                     extra_env=self._portage_extra_env,
                     chroot_args=new_chroot_args)

Looking at the build timeline for some runs, this looks like it takes about 7 hours on its own. So we could save as much as 4 2/3 hours with just this.


[1] But, look at  bug 347804 ; we were worried about 6.5 to 8 hour builds! Ha!