On 10/1/25 6:52 AM, Andre Vehreschild wrote:
Hi all,
attached series of patches adds more stable support for running shared
memory multi process Fortran programs on MacOS. The only new part is the last
(the pr88076_v4_9.patch). Changes in the former files are only results of
rebasing.
On MacOS shared memory coarrays face the issue of having to have the shared
memory segment at the same (virtual) base address in all processes/images, but
the OS not always complying to our wish. The supervisor of the coarray program
therefore now is able to restart an image, when the OS is not complying to put
the shared memory segment where we need to have it. The shared memory segment
needs to be at the same address in all images, because else shared mutexes tend
malfunction. I haven't found any documentation from Apple or the
MachOS kernel why this is that way, but it unfortunately is. The number of
restarts of images is limited. I.e. this is not going on forever, but one can
either set a (documented) environment variable, or got with the default of
4000 at the moment. The count on restarts is total on all images and not per
image.
It took me quite some time to figure what was going on and I had to fix
libsanitizer on macOS for newer OS releases, which being unfamiliar took me
even longer. There might be other issues fixed unintentionally by these
patches. So feel free to test.
Regtested ok on x86_64-pc-linux-gnu / F41, x86_64-w64-win32 / MSYS2 / UCRT64 and
x86_64-apple-darwin24.something. (Testing on MSYS2/UCRT64 gives tons of fails
of 'excess output' tests, which stem from gfortran emitting some escape code,
which doesn't even print, and expect picking it up.)
Regards,
Andre
The devel/gfortran-test branch has been updated to align with the latest
trunk and the version 4 of Andre's patch series applied.
This should allow anyone to checkout this gcc branch and do testing.
All testing is appreciated.
Regards,
Jerry
