Date: Tue, 02 Jan 2024 19:50:56 +0000 From: Jamie Landeg-Jones <jamie@catflap.org> To: freebsd-stable@freebsd.org, jamie@catflap.org, freebsd@omnilan.de Subject: Re: SIGILL when CPUTYPE set to anyting witjh avx and CFLAGS -O2 Message-ID: <202401021950.402Jouvv077682@donotpassgo.dyslexicfish.net> In-Reply-To: <fe65b7ba-ade4-4508-ad8f-1db85e32d179@omnilan.de> References: <accdf012-1b04-4227-9b0c-a78e94133fc2@omnilan.de> <72107B4B-F279-471B-8A8F-5B94C5EEDA47@FreeBSD.org> <62cc8fed-6acd-45fb-a138-ac7cd218191a@omnilan.de> <ZY8qA7SKywXh_Yac@kib.kiev.ua> <e78df80b-f1b1-4297-b681-5db43e07bac0@omnilan.de> <202312311128.3BVBStrp055670@donotpassgo.dyslexicfish.net> <fe65b7ba-ade4-4508-ad8f-1db85e32d179@omnilan.de>
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> Sometimes this might be best, but usually I compile on a dedicated > machine and redistribute to others via local repo. Ahhh, that would be a good reason not to use native then! :-) Still, the "show-clang-native-features" does help identify what features clang things can be enabled on a certain CPU. > At least my latest SIGILL crashes were caused simply by mismatching > target CPU :-( Embarassing... apologies for the noise again. > I didn't know that skylake-avx512 isn't the sequentially the next-Gen., > post SkyLake identifyer, so my assumption that my v6 Xeon would support > AVX512 was simply wrong. Now I know better. And IceLake continues > confusion... (some AlderLakes do have PCONFIG, others not, WBNOINVD > seems completely mainstream-unavailable and tons of feature-flags/units > I never heard before.. (http://instlatx64.atw.hu/) World isn't getting > less complicated... I haven't had recent experience, but I can well believe it! A few years ago, I used to chase feature flags with each release, and there were some weird goings on occasionally. I seem to remember weirdness with BMI at one stage (around 2014), but that was fixed. > Will try to reproduce my -march=haswell crahes I initially recognized > some months ago and in case it is reproducable, pick up this thread again. I know this is a bit of a "go-faster-stripes" issue, but what flags do you use generally? I know I'm opening myself up to ridicule, but my general cflags on most machines maps to : -O2 -pipe -march=native -mtune=native -ftree-vectorize -fstack-protector-strong -fno-strict-aliasing -Wl,-znow -Wl,-zrelro -- some of that added by me, some of it by the FreeBSD build system. > Happy new year to everybody! Cheers, and the same to you and everybody else!
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