Alas, it would appear I have spoken too soon! I experienced a strange build failure with RC1 yesterday and, fearing the worst, did my experiment from a few weeks ago again, with the following result:
– building "Pure" fails in around 6 % of the cases – this does not change even after a cold reboot – switching SMT off seems to make the problem go away entirely – switching SMT on makes it reappear Sounds very much like this might well be the Ryzen bug. AMD has started replacing affected CPUs, so I shall enquire about that and see what happens. Cheers, Manuel On 20/08/17 14:31, Manuel Eberl wrote: > Addendum: I did a system upgrade (including a major kernel upgrade) > around the same time when I first noticed the problem and I don't think > I rebooted afterwards, so one very plausible explanation is that Linux > introduced some workarounds/bug fixes in the kernel within the last few > weeks that solved whatever issue I was having, and, of course, it took a > reboot for it to kick in. > > On 20/08/17 14:14, Manuel Eberl wrote: >> Okay I have no idea what is going on anymore. >> >> I know have the following new data points: >> – 2500 iterations on my Intel Core i7 laptop. No failures. >> >> So it must be the Ryzen issue after all, I thought. I recalled that some >> people said the problem was less pronounced with SMT disabled, so I >> disabled it. >> – 100 iterations on Ryzen 1800X after a reboot with SMT disabled. No >> failures. >> – 100 iterations on Ryzen 1800X after another reboot with SMT enabled >> again. No failures. >> >> So it seems the problem went away as mysteriously as it appeared and it >> probably has something to do with the hardware or software constellation >> on my computer. Or perhaps I should check my flat for radiation sources. >> >> Cheers, >> >> Manuel >> >> >> On 20/08/17 11:24, Lars Hupel wrote: >>>> Lars, maybe you can run the same test on your machine and see what >>>> happens there. >>> >>> I did, and nothing happened for about 100 iterations. I have a Core >>> i7-2600. OS is otherwise identical to Manuel (Arch Linux). >>> >>>> As for Scala, could a problem in the Scala compiler really lead to the >>>> JVM segfaulting? I would have thought if the JVM segfaults, that's a bug >>>> in the JVM. (unless it's a hardware-related issue, of course) >>> >>> I've seen it happening, but it is very rare. Still, the coincidence of >>> crashes during compilation could be explained by random chance (even if >>> very unlikely). A quick look over Scala's issue tracker reveals no >>> documented JVM segfaults after 2011. >>> >>> Cheers >>> Lars >>> _______________________________________________ isabelle-dev mailing list isabelle-...@in.tum.de https://mailmanbroy.informatik.tu-muenchen.de/mailman/listinfo/isabelle-dev
