Bug 2249353 - Enable LLVM BOLT for multiple packages
Summary: Enable LLVM BOLT for multiple packages
Keywords:
Status: CLOSED EOL
Alias: None
Product: Fedora
Classification: Fedora
Component: clang
Version: 40
Hardware: Unspecified
OS: Linux
unspecified
medium
Target Milestone: ---
Assignee: Orphan Owner
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2023-11-12 14:16 UTC by Alexander Zaitsev
Modified: 2025-05-16 07:47 UTC (History)
11 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed: 2025-05-16 07:47:04 UTC
Type: ---
Embargoed:


Attachments (Terms of Use)

Description Alexander Zaitsev 2023-11-12 14:16:15 UTC
Hi!

According to the Facebook Research Paper (https://research.facebook.com/publications/bolt-a-practical-binary-optimizer-for-data-centers-and-beyond/), LLVM BOLT (https://github.com/llvm/llvm-project/blob/main/bolt/README.md) helps with achieving better performance for various packages like compilers and interpreters. I think it would be a good idea to enable LLVM BOLT for some packages to deliver faster binaries for users.

Here I got some examples of how LLVM BOLT is already integrated into other projects:

* Rustc: https://github.com/rust-lang/rust/pull/116352
* CPython: https://github.com/python/cpython/pull/95908
* Pyston:
  - https://github.com/pyston/pyston#building
  - https://github.com/pyston/pyston/blob/pyston_main/Makefile#L200
* Clang: https://github.com/llvm/llvm-project/blob/main/clang/cmake/caches/BOLT.cmake

So at least for the projects above LLVM BOLT effects are tested and some preparations are already done in the upstream projects. In this case, it should be easier to enable BOLT for these packages.

For some projects right now there is ongoing work on integrating LLVM BOLT into the build scripts:

* Chromium: https://bugs.chromium.org/p/chromium/issues/detail?id=1163978
* Firefox: https://bugzilla.mozilla.org/show_bug.cgi?id=1789087
  - The same for Propeller (a LLVM BOLT alternative): https://bugzilla.mozilla.org/show_bug.cgi?id=1509314
* NodeJS: https://github.com/nodejs/node/issues/50379
* LDC: https://github.com/ldc-developers/ldc/issues/4228
* GCC: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112492

More about LLVM BOLT performance results for other projects can be found in:

* Rustc:
  - https://github.com/rust-lang/rust/pull/116352
  - https://www.reddit.com/r/rust/comments/y4w2kr/llvm_used_by_rustc_is_now_optimized_with_bolt_on/
* CPython: https://github.com/python/cpython/pull/95908
* YDB: https://github.com/ydb-platform/ydb/issues/140
* Clang:
  - [Slides](https://llvm.org/devmtg/2022-11/slides/Lightning15-OptimizingClangWithBOLTUsingCMake.pdf)
  - [Results on building Clang](https://github.com/ptr1337/llvm-bolt-scripts/blob/master/results.md)
  - [Linaro results](https://android-review.linaro.org/plugins/gitiles/toolchain/llvm_android/+/f36c64eeddf531b7b1a144c40f61d6c9a78eee7a)
  - [on AMD 7950X3D](https://github.com/llvm/llvm-project/issues/65010#issuecomment-1701255347)
* LDC: https://github.com/ldc-developers/ldc/issues/4228#issuecomment-1334499428
* NodeJS: https://aaupov.github.io/blog/2020/10/08/bolt-nodejs
* Chromium: https://aaupov.github.io/blog/2022/11/12/bolt-chromium
* MySQL, MongoDB, memcached, Verilator: https://people.ucsc.edu/~hlitz/papers/ocolos.pdf

More information about the topic can be found here: https://github.com/zamazan4ik/awesome-pgo

I don't create an issue per project (like "Enable BOLT for Clang", "Enable BOLT for GCC", etc.) since I think first we need to discuss the approach. And if we agree with enabling BOLT, then we can create an additional issue (and use this issue as a BOLT meta issue).

Reproducible: Always

Comment 1 Alexander Zaitsev 2023-11-13 23:53:47 UTC
Also, it could be a good thing to expand Profile-Guided Optimization (PGO) usage across as many packages as possible. Examples of PGO benchmarks for different software can be found here: https://github.com/zamazan4ik/awesome-pgo#pgo-showcases . Providing more performance would be useful for more packages even before enabling LLVM BOLT optimization.

Comment 2 Tulio Magno Quites Machado Filho 2023-11-14 18:22:30 UTC
Alexander, here at Fedora, the package maintainers are free to decide the best way to build their packages.
There is nothing much the team maintaining LLVM BOLT can do here.
If you'd like to see all these package using LLVM BOLT, I suggest that you report a new bugzilla for each of them so that each package maintainer review your suggestion.

With that said, I'm reassigning this bug to Clang.

Comment 3 Alexander Zaitsev 2023-11-15 21:36:54 UTC
> Alexander, here at Fedora, the package maintainers are free to decide the best way to build their packages.


I thought about something like discussing this activity as something like an RFC/proposal to FESCo (https://docs.fedoraproject.org/en-US/fesco/) as a possible place to discuss potentially wide changes to the packages. But I know almost nothing about the Fedora internal processes - just heard about FESCo in local Fedora chats, and maybe this question to too "low-level" for FESCo or any other kind of other Fedora committee.

> If you'd like to see all these package using LLVM BOLT, I suggest that you report a new bugzilla for each of them so that each package maintainer review your suggestion.

Yep. I can do it for many packages (in theory, for *all* C/C++/Rust binaries packages). But probably we need some criteria for creating an issue for a package about PGO. Maybe some existing PGO benchmarks for software? Or any kind of PGO integration in upstream? Need to be discussed.

Comment 4 Tulio Magno Quites Machado Filho 2023-11-22 18:59:08 UTC
(In reply to Alexander Zaitsev from comment #3)
> I thought about something like discussing this activity as something like an
> RFC/proposal to FESCo (https://docs.fedoraproject.org/en-US/fesco/) as a
> possible place to discuss potentially wide changes to the packages. But I
> know almost nothing about the Fedora internal processes - just heard about
> FESCo in local Fedora chats, ...

Before going to FESCo, I suggest to discuss this at https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/
I also recommend to copy the maintainers of each of these packages too.

> ... maybe this question to too "low-level" for
> FESCo or any other kind of other Fedora committee.

No, FESCo does get involved in many low-level discussions.
But again, I believe it's important to have an open discussion with the rest of the Fedora community first.

Comment 5 Aoife Moloney 2024-02-15 23:04:18 UTC
This bug appears to have been reported against 'rawhide' during the Fedora Linux 40 development cycle.
Changing version to 40.

Comment 6 Aoife Moloney 2025-04-25 10:10:21 UTC
This message is a reminder that Fedora Linux 40 is nearing its end of life.
Fedora will stop maintaining and issuing updates for Fedora Linux 40 on 2025-05-13.
It is Fedora's policy to close all bug reports from releases that are no longer
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Comment 7 Fedora Admin user for bugzilla script actions 2025-05-14 03:17:34 UTC
This package has changed maintainer in Fedora. Reassigning to the new maintainer of this component.

Comment 8 Aoife Moloney 2025-05-16 07:47:04 UTC
Fedora Linux 40 entered end-of-life (EOL) status on 2025-05-13.

Fedora Linux 40 is no longer maintained, which means that it
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