[MacPorts] #34540: gaul-devel build varies based on number of CPUs

MacPorts noreply at macports.org
Fri Dec 14 23:39:30 PST 2012

#34540: gaul-devel build varies based on number of CPUs
  Reporter:  ryandesign@…  |      Owner:  vince@…
      Type:  defect        |     Status:  closed
  Priority:  Normal        |  Milestone:
 Component:  ports         |    Version:  2.1.1
Resolution:  wontfix       |   Keywords:
      Port:  gaul-devel    |

Comment (by vince@…):

 There is always a trade-off involved with binaries. For example, Qt
 autodetects the vector units of the processor that performs the
 compilation. If you happen to compile qt4-mac on an Ivy Bridge machine and
 install the resulting binary on a Core Duo Mac, you face the risk of
 crashing due to AVX/SSE4.2 instructions not being supported on the latter
 (that’s what I do, though, and up to now it has been fine). If you proceed
 the other way round, you won’t get the performance boost allowed by the
 new hardware/instructions.
 Since it is better to lose efficiency than to crash, ideally a binary
 should be produced on the oldest machine of a given architecture. That’s
 what plagues all the Window$®™ binary distributions, some of which have to
 be compatible with old Pentium processors…

Ticket URL: <https://trac.macports.org/ticket/34540#comment:6>
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