Thank you Chris, Bill, Greg, and Joe.
Bill Broadley wrote:
Chris Samuel wrote:
In the sense that they have no desire to support
competitors hardware, yes. Not really surprising,
Sure, they could be nice enough to have a flag to disable the check for
non-intel cpus. That way intel could avoid the cost of testing/certification
of AMD cpus and folks that want to take the risk could. There is a binary
floating around that patches binaries to avoid the check.
This is gone:
http://www.swallowtail.org/naughty-intel.html
Improvements were
on the order of 0-15% I believe, nobody reported wrong answers as a result.
The (familiar?) Slashdot/2005 discussion:
http://yro.slashdot.org/article.pl?sid=05/07/12/1320202&tid=142&tid=118&tid=123
another on Ubuntu/2008:
http://ubuntuforums.org/showthread.php?t=824046
Inquirer/2007 article:
http://www.theinquirer.net/inquirer/news/1042378/amd-slaps-intel-over-spec-only-compiler#
if AMD made compilers I doubt they'd try and do
Intel specific optimisations either..
Well the issue wasn't intel not doing AMD specific optimizations, it was intel
enabling optimizations that would benefit both CPUs, only when running on intel.
Currently -xW (SSE,SSE2) seems to be the highest architecture-dependent
optimization the Intel compiler allows for Opterons.
Shanghai, Barcelona, and others have more than SSE2, right?
"-xW" is also what AMD recommends when using Intel compilers:
http://support.amd.com/us/Processor_TechDocs/32035.pdf
Compiler Usage Guidelines, p.25:
"3.3.2 Generic Performance Switches
The switches -xW -ipo -O3 -static are generally recommended."
Gus
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