Re: [gentoo-user] march cflag for Intel Pentium Dual-Core E2160 SLA8Z Malay processor

[gevisz]

вт, 25 сент. 2018 г. в 7:07, gevisz <gevisz@×××××.com>:
>
> вс, 23 сент. 2018 г. в 10:10, Walter Dnes <waltdnes@××××××××.org>:
> >
> > On Thu, Sep 20, 2018 at 01:00:39AM +0300, gevisz wrote
> > > ????, 19 ????????. 2018 ??. ?? 11:38, Walter Dnes <waltdnes@××××××××.org>:
> >
> > > >  According to
> > > > http://www.cpu-world.com/sspec/SL/SLA8Z.html it has...
> > > >
> > > > MMX SSE SSE2 SSE3 SSSE3
> > >
> > > Do you mean that it would be enough to set
> > > CFLAGS="-O2 -pipe mmx sse sse2 sse3 ssse3"
> > > without setting the march cflag at all?
> >
> >   Yes, that would work.  Remember also to include in make.conf
> >
> > CPU_FLAGS_X86="mmx mmxext sse sse2 sse3 ssse3"
>
> The target processor does not support mmxext.

Strange enough but cpuid2cpuflags shows that it does:
# cpuid2cpuflags
CPU_FLAGS_X86: mmx mmxext sse sse2 sse3 ssse3

> >   In your jpeg image, I see that the flags include mmx, sse, sse2, pni,
> > and ssse3. "pni" == "Prescott New Instructions" == "SSE3".  Looking at
> > https://gcc.gnu.org/onlinedocs/gcc-7.3.0/gcc/x86-Options.html#x86-Options
> > I suggest "-march=core2" with CPU_FLAGS_X86 same as above.  The "core2"
> > option uses MMX, SSE, SSE2, SSE3 and SSSE3 instructions, all of which
> > show up in the listing on your jpeg.
>
> Thank you. Looking into https://wiki.gentoo.org/wiki/Safe_CFLAGS#Intel
> I also concluded that for the target processor I should set "-march=core2"
> but I did not know that core2 option is exactly equivalent to setting mmx,
> sse, sse2, sse3 and ssse3 instructions.
>
> So, I decided to spend a day to get my hands on the target computer
> and compile everything on it with "-march=native" no matter how much
> time it takes.
>
> To conclude this thread, I will post the output of the commands
> suggested in this thread later, after the system install will be finished,
> just in case somebody will need them in the future.