Closed Bug 1643738 Opened 5 years ago Closed 5 years ago

Disable parallel XZ compression for update generation

Categories

(Release Engineering :: Release Automation, defect)

Product:
Release Engineering
Component:
Release Automation
Type:
defect

Tracking

(Not tracked)

Status:
RESOLVED FIXED

People

(Reporter: catlee, Unassigned)

References

Details

When I was looking at the impact of the BCJ filters on complete updates, I discovered that we are inadvertently using -T0 as a flag for xz when generating our complete updates.
The impact of this is marginally worse compression, as the file is split up into several blocks that are compressed separately.

e.g. if I re-compress https://archive.mozilla.org/pub/firefox/releases/77.0.1/update/win64/en-US/firefox-77.0.1.complete.mar when forcing -T1, I get a small improvement:

original -T1 -T1, selective BCJ
55,762,961 55,580,501 55,565,253
delta: -182,460 -197,708

We are inheriting -T0 from the environment here: https://searchfox.org/mozilla-central/source/taskcluster/docker/debian-build/Dockerfile#9

See Also: → 1643810

This got fixed as part of bug 1643810

Status: NEW → RESOLVED
Closed: 5 years ago
Resolution: --- → FIXED
Component: Release Automation: Updates → Release Automation
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