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 <b...@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 b...@immure.com | without the discomfort of thought." Austin, TX | - John F. Kennedy _______________________________________________ freebsd-stable@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"