Date: Wed, 17 Dec 2014 20:23:16 -0900 From: Royce Williams <royce@...ho.org> To: john-users@...ts.openwall.com Subject: Re: bleeding-jumbo: make -j random opencl errors On Wed, Dec 17, 2014 at 8:24 AM, Solar Designer <solar@...nwall.com> wrote: > On Wed, Dec 17, 2014 at 07:03:45AM -0900, Royce Williams wrote: >> On two different 64-bit Linux gcc systems using NVIDIA OpenCL and CUDA >> 6.5, a non-parallel make works fine, but parallel makes die randomly >> with errors like the following, but with different errors on some >> attempts. >> >> $ make -j -s >> opencl_mscash2_fmt_plug.c:457:1: internal compiler error: Segmentation fault >> }; > > Why do you use -j, as opposed to -j8 or whatever matches your machine? > Is this a stress test? Do you even have enough RAM for it? I think not. Heh. Point taken. Call it an inadvertent stress test. I'd been doing this for a while and never had a problem. I typo'd it one day (leaving off the number of cores), and since it worked well and finished much faster, I just kept using it. I realized that it was doing a *lot* more "parallelizing" than before, but it seems to be fine until now. > So this looks like a non-issue to me. It is expected behavior to > receive a SIGSEGV on an out of memory condition, as long as some memory > overcommitment is allowed in the kernel. > >> IIRC, this was working a few days ago on at least one of the systems, >> and neither have had this failure mode before. > > Maybe memory usage by this build or by something else on your system has > increased. I'm mildly curious about what changed -- but not enough to waste any more of anyone's time on it, especially during a bugfix-only cycle. > Just do not use -j without specifying a limit, like "-j8" or > e.g. -j32 on our "super" machine. Understood. > We do have a large number of source > files, so plain -j will result in excessive load and likely a slightly > slower build (cache thrashing, extra context switches), and it may very > well run out of memory unless you have lots installed. Thanks -- that helps me understand the root cause. And "lots" clearly must mean something more than the 16G that I have in that system. Back to the real bugs - sorry, guys. Royce
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