Changing CFLAGS for i386 packages on x86_64 (benchmarks included)

Dave Jones davej at redhat.com
Sun Jul 16 12:27:49 UTC 2006


On Sun, Jul 16, 2006 at 08:15:46AM -0400, Dave Jones wrote:
 > On Sun, Jul 16, 2006 at 02:10:22PM +0200, dragoran wrote:
 >  > I did same benchmarks using flops.c (attached) the results are attached 
 >  > to it seems that
 >  > -march=k8 -mtune=k8 -m32 is the fastes but not by much ...

Additionally, whilst you found these flags speed things up
slightly on AMD systems, it may have a noticable detrimental
impact on Intel systems, and shipping multiple sets of binaries
for a negligable speedup doesn't make a lot of sense.

 >  > the last one (-m64) is weird (much slower!!) no -OX was used.

When run in 32bit, this is doubling the amount of loads/stores used,
so little wonder it's slower.

		Dave

-- 
http://www.codemonkey.org.uk




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