perf bench: Make "default" memcpy() selection actually use glibc's implementation
authorJan Beulich <JBeulich@suse.com>
Wed, 18 Jan 2012 13:28:13 +0000 (13:28 +0000)
committerArnaldo Carvalho de Melo <acme@redhat.com>
Tue, 24 Jan 2012 21:50:19 +0000 (19:50 -0200)
commit9ea811973d49a1df0be04ff6e4df449e4fca4fb5
treedb7d041f0a50ed424d131745513620d348d1d8f1
parent0d37aa34f8806bb443dd3c8621fd9bdbb50c58bb
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>
tools/perf/bench/mem-memcpy-x86-64-asm.S