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63e6c5b810
linux-kernel-test/arch/powerpc/lib
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Anton Blanchard 63e6c5b810 powerpc: Pair loads and stores in copy_4k_page 
A number of our chips like loads and stores to be paired. A small kernel
module testcase shows the improvement of pairing loads and stores in
copy_4k_page:

POWER6: +9%
POWER7: +1.5%

#include <linux/module.h>
#include <linux/mm.h>

#define ITERATIONS 10000000

static int __init copypage_init(void)
{
	struct timespec before, after;
	unsigned long i;
	struct page *destpage, *srcpage;
	char *dest, *src;

	destpage = alloc_page(GFP_KERNEL);
	srcpage = alloc_page(GFP_KERNEL);

	dest = page_address(destpage);
	src = page_address(srcpage);

	getnstimeofday(&before);

	for (i = 0; i < ITERATIONS; i++)
		copy_4K_page(dest, src);

	getnstimeofday(&after);

	free_page((unsigned long)dest);
	free_page((unsigned long)src);

	printk(KERN_DEBUG "copy_4K_page loop took %lu ns\n",
		(after.tv_sec - before.tv_sec) * NSEC_PER_SEC +
		(after.tv_nsec - before.tv_nsec));

	return 0;
}

static void __exit copypage_exit(void)
{
}

module_init(copypage_init)
module_exit(copypage_exit)
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Anton Blanchard");

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-02-17 14:03:16 +11:00
..
alloc.c [POWERPC] Limit range of __init_ref_ok somewhat 2007-10-03 11:48:44 +10:00
checksum_32.S
checksum_64.S
code-patching.c PAGE_ALIGN(): correctly handle 64-bit values on 32-bit architectures 2008-07-24 10:47:21 -07:00
copy_32.S powerpc/8xx: Start using dcbX instructions in various copy routines 2009-12-09 17:10:37 +11:00
copypage_64.S powerpc: Pair loads and stores in copy_4k_page 2010-02-17 14:03:16 +11:00
copyuser_64.S powerpc: Fix 64bit __copy_tofrom_user() regression 2009-02-26 14:02:54 +11:00
crtsavres.S [POWERPC] Fix -Os kernel builds with newer gcc versions 2008-06-16 15:00:54 +10:00
devres.c [POWERPC] devres: Add devm_ioremap_prot() 2008-05-05 16:47:14 +10:00
div64.S
feature-fixups-test.S powerpc: Fixup lwsync at runtime 2008-07-03 16:58:10 +10:00
feature-fixups.c powerpc: Fix lwsync patching code on 64bit 2010-02-17 14:03:15 +11:00
locks.c locking: Convert raw_rwlock to arch_rwlock 2009-12-14 23:55:32 +01:00
Makefile powerpc: Add configurable -Werror for arch/powerpc 2009-06-16 14:15:45 +10:00
mem_64.S
memcpy_64.S powerpc: Fix 64bit memcpy() regression 2009-02-26 14:02:53 +11:00
rheap.c powerpc: Fix corruption error in rh_alloc_fixed() 2008-12-17 10:06:14 -06:00
sstep.c powerpc: Don't emulate mr. instructions 2009-02-10 14:39:07 +11:00
string.S powerpc: Use PPC_LONG and PPC_LONG_ALIGN in lib/string.S 2008-07-22 10:39:35 +10:00
usercopy_64.c