Parallelize gcc lto
Nobody has claimed this yet.
- Dominant language
- C++
- Stars
- 238
- Forks
- 106
- Avg merge
- 2h 29m
- Merged PRs (30d)
- 6
Description
gcc allows passing the number of threads for parallelization to use at link time with LTO. Since gcc 10.x this can be set automatically with -flto=auto which will use either GNU Make's job server or fallback to detecting the number of available CPU threads (see the gcc documentation)
An additional ifeq check can be added to makefile around line 74. This will silence the lto-wrapper warning that currently pops up about serial compilation of LTRANS jobs when compiling with gcc and STAN_CPP_OPTIMS enabled and hopefully decrease the linking time.
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start in makefile around line 74 and review the GCC LTO options described in the linked GCC documentation. Check the build path used when STAN_CPP_OPTIMS is enabled, then verify with GCC that the LTRANS serial-compilation warning is silenced and linking uses parallelism.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- cpp
- Domain
- build-system
- Issue type
- Feature
- Difficulty
- 2/5
- Estimated time
- 1-3 hours
- Activity status
- Stale
- Clarity
- Clearly specified
- Newbie friendliness
- 48/100