F39 proposal: Modernize Thread Building Blocks for Fedora 39 (System-Wide Change proposal)
https://fedoraproject.org/wiki/Changes/F39ModernizeTBB
This document represents a proposed Change. As part of the Changes
process, proposals are publicly announced in order to receive
community feedback. This proposal will only be implemented if approved
by the Fedora Engineering Steering Committee.
== Summary ==
Fedora is currently shipping version 2020.3 (released July 10, 2020)
of the Thread Building Blocks library. The current upstream version is
2021.8 (released December 22, 2022). The Fedora community has
expressed [https://bugzilla.redhat.com/show_bug.cgi?id=2036372
interest] in moving the TBB package to track a more modern version of
the upstream.
== Owner ==
* Name: [[User:trodgers| Thomas Rodgers]]
* Email: trodgers(a)redhat.com
== Detailed Description ==
Fedora has shipped with version 2020.3 of the Thread Building Blocks
library since Fedora 33. The
upstream project made a decision to break backward compatibility after
that version was released.
As packages move to match the upstream's changes it becomes more
difficult to defer updating the
Fedora packaging for TBB. The situation is further complicated as
there are currently a majority
of TBB dependent packages which have not been updated to track a new
upstream release, as detailed in this
[https://bugzilla.redhat.com/show_bug.cgi?id=2036372#c1 analysis] on
the tracking issue.
This proposal aims to provide a way to modernize the TBB packge
version for Fedora while providing stability for those packages which
continue to depend on the older TBB library version.
It will be possible to install both devel and runtime versions of both
TBB packages, however the devel compat package for version 2020.3 will
require clients to point to a new include path where the legacy
headers will be found.
== Feedback ==
== Benefit to Fedora ==
Fedora 39 will include a current version of Thread Building Blocks
(version 2021.8) while continuing to support clients dependent on an
older version of TBB (version 2020.3). Fedora will stay relevant as
far as Thread Building Blocks clients are concerned.
== Scope ==
* Proposal owners:
** A compat package based on the current 2020.3 version of the
existing TBB package will be created.
** Evaluate TBB dependent packages to identify those which need to
move to the compat version of the TBB package. An initial analysis
suggests the majority of current TBB clients will need to move to the
compat package.
** Post a request for rebuilds to fedora-devel
** Create patches for those packages affected by this change to adjust
their includes to point the compat package's headers as necessary,
work with affected package owners to update package specs to account
for the change.
** When most packages are done, re-tag all the packages in rawhide.
** Watch fedora-devel and assist in rebuilding broken TBB clients.
* Other developers:
** Those who depend on Thread Building Blocks will have to rebuild
their packages. Feature owners will alleviate some of this work as
indicated above, and will assist those whose packages fail to build in
debugging them.
* Release engineering: TODO <!-- [https://pagure.io/releng/issues
#Releng issue number] -->
* Policies and guidelines: N/A (not needed for this Change)
** Apart from scope, this is business as usual, so no new policies, no
new guidelines.
== Upgrade/compatibility impact ==
* No manual configuration or data migration needed.
* Some impact on other packages needing code changes to rebuild.
== How To Test ==
* No special hardware is needed.
* Parallel install of the 2020.3 TBB compat packages and the updated
TBB packages and checking that it does not break other packages.
== User Experience ==
* Expected to remain largely the same.
* Developers building third-party software on Fedora may need to
rebuild against the new TBB packages, and may need to adjust their
code to either remain on the compat TBB version or move to the new
version supplied by the updated TBB package.
== Dependencies ==
Packages that must be rebuilt:
<code>& dnf repoquery -s --releasever=rawhide --whatrequires libtbb\*
--enablerepo=fedora | sort -u</code>
The tracking [https://bugzilla.redhat.com/show_bug.cgi?id=2036372
issue's] analysis suggests that only the following packages will be
able to move to a newer TBB -
* fawkes
* gazebo
* opencascade
* pmemkv
* root
While the remaining clients of TBB will need to have their spec's
include paths adjusted to use the 2020.3 compat package.
== Contingency Plan ==
* Contingency mechanism: Worst case scenario is to abandon the update
and simply ship F39 with the existing TBB package, which is already in
rawhide.
== Documentation ==
* Notes on the scope of change, motivation, and likely impacts are in
the comments on the tracking
[https://bugzilla.redhat.com/show_bug.cgi?id=2036372 issue].
* https://github.com/oneapi-src/oneTBB/releases/tag/v2021.7.0
(Released 2nd October 2022)
* https://github.com/oneapi-src/oneTBB/releases/tag/v2020.3 (Released
10th July 2020)
== Release Notes ==
<!-- TODO -->
--
Ben Cotton
He / Him / His
Fedora Program Manager
Red Hat
TZ=America/Indiana/Indianapolis