[Pkg-julia-devel] Bug#816980: Bug#816980: julia: FTBFS in testing

[Peter Colberg]

Hi Santiago,

On Thu, Apr 28, 2016 at 05:31:25PM +0200, Santiago Vila wrote:
> Sorry, I can't reproduce this consistently, but when the problem
> happens, I see a segfault like this in dmesg:
> 
> [ 5377.752190] julia[21086]: segfault at 20000ffe2 ip 00007f033628b807 sp 00007ffc819cbdb0 error 4 in libjulia.so[7f03361ed000+eb000]
> 
> which I think it is the result of bad memory handling.

Can you reproduce this sporadic error on multiple machines with
different hardware? If not, does memtest86+ pass on that machine?

What are the hardware specs of the machine(s)?

> I think part of the problem is that parallel builds are enabled no
> matter the number of CPUs I have. In the logs, I see this:
> 
> env JULIA_CPU_CORES=2 [...]
> 
> and in fact debian/rules has this:
> 
> # Set number of parallel workers for tests
> ifneq (,$(filter parallel=%,$(DEB_BUILD_OPTIONS)))
> TESTS_ENV += JULIA_CPU_CORES=$(patsubst parallel=%,%,$(filter parallel=%,$(DEB_BUILD_OPTIONS)))
> else ifeq (,$(filter parallel,$(DEB_BUILD_OPTIONS)))
> TESTS_ENV += JULIA_CPU_CORES=2
> endif
> 
> I'm not sure if this is policy compliant or not, but I think the
> number of cores to be used should be limited in either case by the number
> of actual CPUs available, as there is little point in using parallel
> builds (or parallel workers for test suite) when you have only one CPU.

The tests are run with a minimum of 2 processes regardless of the
number of available CPUs. This is *required* since one of the
processes supervises and restarts the other process when the
memory limit per process is exceeded.

As Graham has written earlier, julia builds fine even on a system
with only 1 CPU and 1 GB. Either your hardware is defect, or you
have a special setup and we need to find out what is special.

Regards,
Peter