Date: Tue, 23 Apr 2019 17:04:33 -0500 From: Bob Willcox <bob@immure.com> To: Lorenzo Salvadore <phascolarctos@protonmail.ch> Cc: "freebsd-stable@freebsd.org" <freebsd-stable@freebsd.org> Subject: Re: 12.0 installworld core dumping on me Message-ID: <20190423220433.GM6607@rancor.immure.com> In-Reply-To: <VY5IVXkeYqjAiEfioKjBj3VOk6dV13_mlTIWo1NCenI8KJZyEGp70nJzsZqknw8c-BjXI6RlICv3lL71vZ-V-iQ4l03px0useGS69QA5svI=@protonmail.ch> References: <20190423125133.GG3392@rancor.immure.com> <20190423183604.GL6607@rancor.immure.com> <VY5IVXkeYqjAiEfioKjBj3VOk6dV13_mlTIWo1NCenI8KJZyEGp70nJzsZqknw8c-BjXI6RlICv3lL71vZ-V-iQ4l03px0useGS69QA5svI=@protonmail.ch>
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On Tue, Apr 23, 2019 at 08:43:34PM +0000, Lorenzo Salvadore via freebsd-stable wrote: > ????????????????????? Original Message ????????????????????? > On Tuesday 23 April 2019 20:36, Bob Willcox <bob@immure.com> wrote: > ... > > I am playing too with CPUTYPE in these days. I think I will soon write a wiki page > about that. Here is a short description of what I have found out. > > What I suggest you to do, if you still want to play with CPU_TYPE (I do not recommend it: > I cannot see any real improvement), is to set CPUTYPE?= native. Then look into > /usr/share/mk/bsd.cpu.mk what feature you can enable or disable for your processor: > avx, sse3 etc. Compare this list with the feature supported by your processor (run > "dmesg | head -n 25" to get them) and define MACHINE_CPU+= with what you need > (some features probably are already set: check them with "make -V MACHINE_CPU"). > > Reading /usr/share/mk/bsd.cpu.mk you will see some values you can give to CPUTYPE > that will set automatically MACHINE_CPU to the right value. However I discourage you > from using them: in my case, I should set CPU_TYPE?=ivybridge, however bsd.cpu.mk, > clang and gcc all believe that ivybridge support avx, but this is wrong at least for my > cpu, thus I get invalid instructions (even if I correct bsd.cpu.mk), while everything is > fine by setting CPU_TYPE?=native. > If, however, you still want to set your specific model instead of native into CPU_TYPE, > you can get the supposed right value running > "cc -v -x c -E -march=native /dev/null -o /dev/null" or "llvm-tblgen -version". > > If you happen to encounter some invalid instructions with some port, recompile it > with NO_CPU_CFLAGS=yes: this will avoid setting -march=<CPU_TYPE> in > your CFLAGS. > I had to do that with ports involving rust. > > Lorenzo Salvadore. Thanks for the info/insight Lorenzo. I think I will simply skip setting it from now on though. I burned/wasted way more time on this than I care to think about already. It sounds like (based on what you have said) there really isn't a big reward for using it anyway. Thanks again, Bob -- Bob Willcox | "Too often we enjoy the comfort of opinion bob@immure.com | without the discomfort of thought." Austin, TX | - John F. Kennedy
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