feat(run-task): enable parallel git checkout - #1041
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With one worker per core the cold checkout write of the Firefox tree went
from 27.9s to 13.3s on a GCP c3d-standard-8 docker worker and from 111.6s to
36.0s on an Azure Standard_F8alds_v7 Windows worker.
Nice win!
The git docs note that parallel checkout can be slower on spinning disks or machines with very few cores.
Doesn't need to block this, but perhaps worth considering adding an env var to make it possible to disable this, in case this comes up in practice?
Holding off approving this patch until it's actually mergeable.
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Sure, I'll add it. |
ahochheiden
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git writes the working tree with one thread unless checkout.workers is set. With one worker per core the cold checkout write of the Firefox tree went from 27.9s to 13.3s on a GCP c3d-standard-8 docker worker and from 111.6s to 36.0s on an Azure Standard_F8alds_v7 Windows worker. Warm updates and blobless sparse checkouts did not change, since there the fetch dominates. The setting sits next to safe.directory in the global config, needs git 2.32, and older gits ignore the key. The git docs note that parallel checkout can be slower on spinning disks or machines with very few cores. Fixes taskcluster#1040
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Fixes #1040
Stacked on #1039, only the top commit is new here.
Cold checkouts of the Firefox tree went from 27.9s to 13.3s on Linux and 111.6s to 36.0s on Windows. Git older than 2.32 ignores the settings.