I did a time map of a Fedora compose today, and noticed that we
spend about an hour waiting for the ostree_install phase to
complete before we start up the compose_images_phase which does
all the other image builds.
This is unnecessary. Nothing else depends on ostree_install; it
should be fine to start up the extra_phase (which contains
compose_images_phase) while the ostree stuff is still running.
This implements that by splitting the ostree phases out of the
essentials_phase which contains the real precursors to the
extra_phase. We start the essentials and ostree phases together,
but only wait for the essentials phase to complete before
kicking off extra_phase, so it can start while the ostree
phase is still running.
One tweak we have to make to accommodate this is to move
image_checksum_phase out of extra_phase, to avoid it potentially
running before all ostree installer images are built. The
checksum phase is quite fast - it takes about five minutes -
and any time benefit of running it in parallel with the osbs and
repoclosure phases seems like it must be smaller than the time
loss of waiting for ostree_install before kicking off extra.
Merges: https://pagure.io/pungi/pull-request/1790
Signed-off-by: Adam Williamson <awilliam@redhat.com>
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