[MacPorts] #68746: Expand using Profile-Guided Optimization (PGO) for MacPorts packages

[MacPorts]

#68746: Expand using Profile-Guided Optimization (PGO) for MacPorts packages
-------------------------+-----------------------------
 Reporter:  zamazan4ik   |      Owner:  (none)
     Type:  enhancement  |     Status:  new
 Priority:  Normal       |  Milestone:  MacPorts Future
Component:  ports        |    Version:
 Keywords:  pgo          |       Port:
-------------------------+-----------------------------
 Hi!

 Now I am investigating Profile-Guided Optimization (PGO) effects on
 different kinds of software - all my current results are available at
 https://github.com/zamazan4ik/awesome-pgo. According to these results,
 enabling PGO can help with achieving better overall performance in many
 cases. I think expanding PGO usage for the MacPorts packages would be a
 good idea since it could help to achieve better software performance and
 lower battery usage.

 ### Profile-Guided Optimization (PGO)

 PGO is already a well-known technique. All currently known PGO effects on
 performance can be found at https://github.com/zamazan4ik/awesome-pgo#pgo-
 showcases . Several OS distros already enabled PGO for some packages like
 GCC, Rustc, Chromium, Firefox, and others (it depends on each OS distro,
 of course).

 I think we can try to expand PGO usage across MacPorts packages. I think
 we can start by enabling PGO at least for the following projects (these
 packages are already PGO-optimized in many OS distros):

 * Compilers like Clang, Rust (`rustc`), and others
 * Expand PGO usage for more LLVM tooling - [PGO
 benchmark](https://github.com/llvm/llvm-project/issues/63486) like clang-
 format, Clangd, etc.
 * Databases like SQLite
 * Small utilities Difftastic - [PGO
 benchmark](https://github.com/Wilfred/difftastic/issues/588)

 I am sure it's possible to find more packages with upstream PGO support or
 for which enabling PGO could be an interesting option - all known for me
 PGO optimization results are available at https://github.com/zamazan4ik
 /awesome-pgo#pgo-showcases . As far as I know, CPython and SWI-Prolog are
 the only projects with enabled PGO in MacPorts.

 ### Additional optimization - Post Link Optimization (PLO)

 Regarding Post Link Optimization (PLO), right now there are two main tools
 - LLVM BOLT and Google Propeller.

 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 (since Propeller is less
 stable right now in my opinion). Unfortunately, right now LLVM BOLT does
 not support the macOS platform (see https://github.com/llvm/llvm-
 project/issues/72205). If you are interested in using LLVM BOLT on macOS -
 please vote for adding macOS support to LLVM BOLT in the upstream.

 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

 Some OS already using LLVM BOLT in their build scripts -
 [check](https://github.com/getsolus/packages/blob/main/packages/l/llvm/package.yml#L116)
 Clang recipe in Solus.


 With this issue, I want to start a discussion about providing more
 advanced optimizations to the MacPorts packages before actual issue
 creation. I don't create an issue per project (like "Enable BOLT for
 Clang", "Enable PGO for GCC", etc.) since I think first we need to discuss
 the approach. If we agree on expanding PGO usage for some packages, then
 we can create an additional issue (and use this issue as a meta issue). In
 this issue, we can discuss approaches regarding PGO and PLO.

-- 
Ticket URL: <https://trac.macports.org/ticket/68746>
MacPorts <https://www.macports.org/>
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