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perf bench: Make "default" memcpy() selection actually use glibc's implementation 

Since arch/x86/lib/memcpy_64.S implements not only __memcpy, but also
memcpy, without further precautions this function will get chose by the
static linker for resolving all references, and hence the "default"
measurement didn't really measure anything else than the
"x86-64-unrolled" one.

Fix this by renaming (through the pre-processor) the conflicting symbol.

On my Westmere system, the glibc variant turns out to require about 4%
less instructions, but 15% more cycles for the default 1Mb block size
measured.

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/4F16D6FD020000780006D72F@nat28.tlf.novell.com
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Jan Beulich 2012-01-18 13:28:13 +00:00 committed by Arnaldo Carvalho de Melo
parent 0d37aa34f8
commit 9ea811973d
1 changed files with 1 additions and 1 deletions
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2
tools/perf/bench/mem-memcpy-x86-64-asm.S
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@ -1,2 +1,2 @@
#define memcpy MEMCPY /* don't hide glibc's memcpy() */
#include "../../../arch/x86/lib/memcpy_64.S"