Re: Running out of RAM building devel/llvm13

On Sun, Nov 07, 2021 at 12:38:20AM +0100, Dimitry Andric wrote:
> On 6 Nov 2021, at 23:53, Stephen Montgomery-Smith <montgomerysmithstephen@gmail.com> wrote:
> > 
> > Does anyone else have the problem of running out of RAM when building devel/llvm13?  I have 6 CPUS, 4G of RAM, and 4G of swap.
> > 
> > I can solve it by building with MAKE_JOBS_UNSAFE=yes, but then the build is so slow.
> > 
> > It seems that there is a small part of the build which requires a lot of RAM, and it would be nice to restrict just that portion of the build to just one CPU.
> 
> Try turning off the FLANG option. In my release testing for llvm 13.0.0 I found this eats up most of the memory during a build.

If you turn of FLANG, I also recommend disabling MLIR.  It's nominally a
separate thing with other uses, but I believe only flang uses it in tree.
If we could isolate which file(s) use too much memory it might be
possible for upstream to put in an exception to single-thread around
them.

BTW, which architecture are you building for?

-- Brooks