[MacPorts] #48381: OpenBlas: difficulty detecting architecture

[MacPorts]

#48381: OpenBlas: difficulty detecting architecture
--------------------------+---------------------
  Reporter:  aaron.koe@…  |      Owner:  nicos@…
      Type:  defect       |     Status:  new
  Priority:  Normal       |  Milestone:
 Component:  ports        |    Version:  2.3.3
Resolution:               |   Keywords:
      Port:  openblas     |
--------------------------+---------------------

Comment (by andy.nowacki@…):

 I can confirm that the patched port of OpenBLAS builds and a test program
 runs successfully after r139234.  However, I guess the patch added might
 be having an unexpected effect when added to the 0.2.14 release.  It seems
 to incorrectly identify the machine as having a Nehalem processor, not
 Broadwell:

 {{{
 $
 /opt/local/var/macports/build/_Users_user_macports_trunk_dports_math_OpenBLAS/OpenBLAS/work/OpenBLAS-0.2.14/getarch
 0
 CORE=NEHALEM
 LIBCORE=nehalem
 -- snip --
 $
 /opt/local/var/macports/build/_Users_user_macports_trunk_dports_math_OpenBLAS/OpenBLAS/work/OpenBLAS-0.2.14/getarch
 1
 #define NEHALEM
 -- snip --
 #define CORE_NEHALEM
 #define CHAR_CORENAME "NEHALEM"
 }}}

 The same command on the OpenBLAS-devel branch gives the following output:
 {{{
 $ ./getarch 0
 CORE=HASWELL
 LIBCORE=haswell
 --snip --
 $ ./getarch 1
 #define HASWELL
 #define L2_SIZE 262144
 -- snip --
 #define CORE_HASWELL
 #define CHAR_CORENAME "HASWELL"
 }}}

 The major difference is that the devel branch defines HAVE_FMA3.

 A test program (mul.f90, attached) runs faster using the devel branch than
 the 0.2.14 release port, which leads me to think that the
 misidentification of the Broadwell processor in the MacBook Pro is
 responsible.

 {{{
 $ ### Link to OpenBLAS at git commit
 bb6e050509dc9aeb71f525b42444df57df2589d4 built at /tmp/OpenBLAS
 $ gfortran -L/tmp/OpenBLAS/lib -lopenblas -fexternal-blas -fblas-matmul-
 limit=1 -o /tmp/a.out /tmp/mul.f90 && time /tmp/a.out 5000

 real    0m4.423s
 user    0m7.901s
 sys     0m0.485s

 $ ### Link to MacPorts OpenBLAS @0.2.14_2 +gcc48
 $ gfortran -L/opt/local/lib -lopenblas -fexternal-blas -fblas-matmul-
 limit=1 -o /tmp/a.out /tmp/mul.f90 && time /tmp/a.out 5000

 real    0m10.685s
 user    0m20.366s
 sys     0m0.492s
 }}}

 (Note that the numbers using -framework Accelerate for Apple's BLAS are
 very similar to OpenBLAS-devel.)

 Sorry to be the bearer of bad news.

-- 
Ticket URL: <https://trac.macports.org/ticket/48381#comment:9>
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