On Sat, Oct 05, 2024 at 01:50:14AM +0200, Santiago Vila wrote: > El 4/10/24 a las 20:37, Bill Allombert escribió: > > > The test suite works with 3th generation AMD EPYC processorss, > > > but fails with 4th generation. > > > > Ah! Does the VM set /proc/cpuinfo correctly ? > > I don't know. Is there an easy way to check that "/proc/cpuinfo is correct"? > > > Some years ago, I have seen problem when VM advertised support for CPU > > features. > > that where not actually supported. > > That would be certainly surprising from AWS, I would suppose they have > good engineers for such things.
But that make them dangerous :) > On a c7a.large instance (EPYC 4th generation), the first one exits with > exit status 0, but then: "mlucas -s m" segfaults, and creates a core > which I've just put here in case it helps: > > https://people.debian.org/~sanvila/build-logs/mlucas/core.gz > > (gdb says "Core was generated by `/usr/libexec/mlucas/mlucas-avx512 -s m'") > > (Beware: It's 956 MB big when uncompressed). I get a 403 error, I suppose you need to use chmod. But maybe we should skip trying to debug mlucas-avx512 and just remove it. %wget 'https://people.debian.org/~sanvila/build-logs/mlucas/core.gz' --2024-10-05 10:43:18-- https://people.debian.org/~sanvila/build-logs/mlucas/core.gz Résolution de people.debian.org (people.debian.org)… 2607:f8f0:614:1::1274:67, 209.87.16.67 Connexion à people.debian.org (people.debian.org)|2607:f8f0:614:1::1274:67|:443… connecté. requête HTTP transmise, en attente de la réponse… 403 Forbidden 2024-10-05 10:43:19 erreur 403 : Forbidden. > I attach the contents of /proc/cpuinfo for the c6a.large and c7a.large > instances. So the Epyc 3 does not implement AVX512 but Epyc 4 does, as expected. > > Maybe one of those is broken and I can just remove it. > > (I already disabled sse2 on i386 due to crashes) > > Looks reasonable, since this is also a crash. Before I do that, could you check that /usr/libexec/mlucas/mlucas-avx2 actually pass the test-suite on epyc 4, just to be sure ? Then I make a 3rd NMU without mlucas-avx512. Thanks for all you work on this! Bill.
