https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125584

--- Comment #10 from ro at CeBiTec dot Uni-Bielefeld.DE <ro at CeBiTec dot 
Uni-Bielefeld.DE> ---
> --- Comment #8 from Andre Vehreschild <vehre at gcc dot gnu.org> ---
> The idea of not changing the memory size for testing was to test what a user
> would run. So to say, the test was very successful, because it showed that the
> choosen default is to larger for some systems.

The current default may be reasonable for regular users running a single
program using caf_shmem on their own system.  As soon as you're running
in a shared environment (e.g. on a multiuser system or in a testsuite
run with many tests running in parallel), this is no longer acceptable.

> Therefore let's collect opinions on how to resolve this: Should the testsuite
> be modified and use a smaller segment size on non-lazy backing memory
> allocating OSes? Or should this just be documented and be configured
> individually by the runner of the test, i.e. not in the suite, but by a
> environment variable on the system the tests run on? Any more thoughts?

The testsuite needs to have safe defaults: simply using defaults that a
*known* to cause resource exhaustion in some envionments and expecting
affected users to search for a workaround and apply them on their own
won't do.  Imagine a bunch of libgomp tests that uses the default of
using <nproc> threads: you'd quickly become very famous (and very much
shot down) for such a test.  libgomp/testsuite/Makefile.am is extra
careful to avoid such a scenario, limiting OMP_NUM_THREADS to 8.  The
caf tests need to do the same.

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