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

[james <garftd@verizon.net>]

On 9/23/18 3:20 AM, Walter Dnes wrote:
> On Thu, Sep 20, 2018 at 01:00:39AM +0300, gevisz wrote
>> ????, 19 ????????. 2018 ??. ?? 11:38, Walter Dnes <waltdnes@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"
> 
>   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.
> 
> https://en.wikipedia.org/wiki/SSE3
>> SSE3, Streaming SIMD Extensions 3, also known by its Intel code name
>> Prescott New Instructions (PNI), is the third iteration of the SSE
>> instruction set for the IA-32 (x86) architecture.
> 

Here is some short docs (by MG) on the subject, that are good to save
for future reference::


https://nlug.ml1.co.uk/2016/09/gentoo-portage-cpu_flags_x86-introduction-2015-01-28/5332

or in the gentoo wiki::
https://wiki.gentoo.org/wiki/CPU_FLAGS_X86

Note, some years ago, distcc was excellent as I used it daily. Like
most codes it changes/stresses over the years. So follow distcc
details closely if you intend for it's dependable results. Perhaps
someone (gentoo) is using it in a CI/CD configuration, which would
be of keen interest to many.


hth,
James