Just to be clear, the issue might not be a traditional C/C++ byild step. All LLVM projects at times run something called llvm-tblgen that takes X.td files (target description) and produces c++ and other formats from them. These can take as much or sometimes more memory than just the regular clang build steps. That said, i have not seen them take anything that would make an allocation of 1GB per process not enough, but I just mention it as you need to watch out for these as much as anything else.
> On 7 Mar 2025, at 6:19 pm, Ryan Carsten Schmidt <ryandes...@macports.org> > wrote: > > On Mar 7, 2025, at 04:32, Chris Jones via wrote:. >> >> Kenneth please open a trac ticket with more details, how many thread are >> start for you, where in the build specifically do you have issues etc. > > And please check Activity Monitor's Memory tab while a flang-20 build that is > exhibiting this problem is underway. I checked a few build machines that are > currently building flang-20 and did not see high memory use at that moment, > but it might only happen at certain times during the build. If you see high > memory use, attach to the ticket a screenshot from Activity Monitor or let us > know about how much memory the clang processes were taking. Also make sure > you're not low on disk space since that can also lead to slowness. > > And just to answer the question you asked, yes, you can tell MacPorts not to > start multiple simultaneous build commands with: > > sudo port install flang-20 build.jobs=1 > > However, to reproduce the problem to get the information from Activity > Monitor, just do the build normally, letting MacPorts start many jobs.
