Messages in this thread Patch in this message | | | Date | Wed, 18 Jan 2012 13:28:13 +0000 | From | "Jan Beulich" <> | Subject | [PATCH 1/4] perf/x86-64: make "default" memcpy() selection actually use glibc's implementation |
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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.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/tools/perf/bench/mem-memcpy-x86-64-asm.S +++ b/tools/perf/bench/mem-memcpy-x86-64-asm.S @@ -1,2 +1,2 @@ - +#define memcpy MEMCPY /* don't hide glibc's memcpy() */ #include "../../../arch/x86/lib/memcpy_64.S"
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