Commit 800eb014 authored Jan 18, 2012 by Jan Beulich Committed by Arnaldo Carvalho de Melo Jan 24, 2012

perf bench: Also allow measuring alternative memcpy implementations

Intended to be able to support the current selection of the preferred
memcpy() implementation, this patch adds the ability to also measure the
two alternative implementations, again by way of using some
pre-processsor replacement.

While on my Westmere system this proves that the movsb based variant is
worse than the movsq based one (since the ERMS feature isn't there), it
also shows that here for the default as well as small sizes the unrolled
variant outperforms the movsq one.

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/4F16D728020000780006D732@nat28.tlf.novell.com


Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

parent 9ea81197

tools/perf/bench/mem-memcpy-x86-64-asm-def.h

+8 −0

Original line number	Original line	Diff line number	Diff line
	@@ -2,3 +2,11 @@
	MEMCPY_FN(__memcpy,		MEMCPY_FN(__memcpy,
	"x86-64-unrolled",		"x86-64-unrolled",
	"unrolled memcpy() in arch/x86/lib/memcpy_64.S")		"unrolled memcpy() in arch/x86/lib/memcpy_64.S")

			MEMCPY_FN(memcpy_c,
			"x86-64-movsq",
			"movsq-based memcpy() in arch/x86/lib/memcpy_64.S")

			MEMCPY_FN(memcpy_c_e,
			"x86-64-movsb",
			"movsb-based memcpy() in arch/x86/lib/memcpy_64.S")

tools/perf/bench/mem-memcpy-x86-64-asm.S

+4 −0

Original line number	Original line	Diff line number	Diff line
	#define memcpy MEMCPY /* don't hide glibc's memcpy() */		#define memcpy MEMCPY /* don't hide glibc's memcpy() */
			#define altinstr_replacement text
			#define globl p2align 4; .globl
			#define Lmemcpy_c globl memcpy_c; memcpy_c
			#define Lmemcpy_c_e globl memcpy_c_e; memcpy_c_e
	#include "../../../arch/x86/lib/memcpy_64.S"		#include "../../../arch/x86/lib/memcpy_64.S"