Jan --
I assume the 12% faster is on a benchmark...
Have you measured how much faster the copy_page_sse2
routine (standalond) is than the memcpy? Is it a
factor of 2?
Thanks,
Dan
> -----Original Message-----
> From: Jan Beulich [mailto:jbeulich@xxxxxxxxxx]
> Sent: Wednesday, November 12, 2008 2:38 AM
> To: xen-devel@xxxxxxxxxxxxxxxxxxx
> Subject: [Xen-devel] [PATCH] x86: add SSE-based copy_page()
>
>
> In top of the highmem asstance hypercalls added earlier, this provides
> a performance improvement of another 12% (measured on Xeon E5345) for
> the page copying case.
>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
>
> Index: 2008-10-27/xen/arch/x86/Makefile
> ===================================================================
> --- 2008-10-27.orig/xen/arch/x86/Makefile 2008-11-11
> 16:19:45.000000000 +0100
> +++ 2008-10-27/xen/arch/x86/Makefile 2008-11-11
> 16:18:36.000000000 +0100
> @@ -11,6 +11,7 @@ subdir-$(x86_64) += x86_64
> obj-y += apic.o
> obj-y += bitops.o
> obj-y += clear_page.o
> +obj-y += copy_page.o
> obj-y += compat.o
> obj-y += delay.o
> obj-y += dmi_scan.o
> Index: 2008-10-27/xen/arch/x86/copy_page.S
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ 2008-10-27/xen/arch/x86/copy_page.S 2008-06-03
> 14:24:57.000000000 +0200
> @@ -0,0 +1,66 @@
> +#include <xen/config.h>
> +#include <asm/page.h>
> +
> +#ifdef __i386__
> +#define src_reg %esi
> +#define dst_reg %edi
> +#define WORD_SIZE 4
> +#define tmp1_reg %eax
> +#define tmp2_reg %edx
> +#define tmp3_reg %ebx
> +#define tmp4_reg %ebp
> +#else
> +#define src_reg %rsi
> +#define dst_reg %rdi
> +#define WORD_SIZE 8
> +#define tmp1_reg %r8
> +#define tmp2_reg %r9
> +#define tmp3_reg %r10
> +#define tmp4_reg %r11
> +#endif
> +
> +ENTRY(copy_page_sse2)
> +#ifdef __i386__
> + push %ebx
> + push %ebp
> + push %esi
> + push %edi
> + mov 6*4(%esp), src_reg
> + mov 5*4(%esp), dst_reg
> +#endif
> + mov $PAGE_SIZE/(4*WORD_SIZE)-3, %ecx
> +
> + prefetchnta 2*4*WORD_SIZE(src_reg)
> + mov (src_reg), tmp1_reg
> + mov WORD_SIZE(src_reg), tmp2_reg
> + mov 2*WORD_SIZE(src_reg), tmp3_reg
> + mov 3*WORD_SIZE(src_reg), tmp4_reg
> +
> +0: prefetchnta 3*4*WORD_SIZE(src_reg)
> +1: add $4*WORD_SIZE, src_reg
> + movnti tmp1_reg, (dst_reg)
> + mov (src_reg), tmp1_reg
> + dec %ecx
> + movnti tmp2_reg, WORD_SIZE(dst_reg)
> + mov WORD_SIZE(src_reg), tmp2_reg
> + movnti tmp3_reg, 2*WORD_SIZE(dst_reg)
> + mov 2*WORD_SIZE(src_reg), tmp3_reg
> + movnti tmp4_reg, 3*WORD_SIZE(dst_reg)
> + lea 4*WORD_SIZE(dst_reg), dst_reg
> + mov 3*WORD_SIZE(src_reg), tmp4_reg
> + jg 0b
> + jpe 1b
> +
> + movnti tmp1_reg, (dst_reg)
> + movnti tmp2_reg, WORD_SIZE(dst_reg)
> + movnti tmp3_reg, 2*WORD_SIZE(dst_reg)
> + movnti tmp4_reg, 3*WORD_SIZE(dst_reg)
> +
> +#ifdef __i386__
> + pop %edi
> + pop %esi
> + pop %ebp
> + pop %ebx
> +#endif
> + sfence
> + ret
> Index: 2008-10-27/xen/arch/x86/domain.c
> ===================================================================
> --- 2008-10-27.orig/xen/arch/x86/domain.c 2008-11-11
> 14:55:44.000000000 +0100
> +++ 2008-10-27/xen/arch/x86/domain.c 2008-11-11
> 16:24:48.000000000 +0100
> @@ -183,7 +183,8 @@ static int setup_compat_l4(struct vcpu *
> /* This page needs to look like a pagetable so that it
> can be shadowed */
> pg->u.inuse.type_info = PGT_l4_page_table|PGT_validated|1;
>
> - l4tab = copy_page(page_to_virt(pg), idle_pg_table);
> + l4tab = page_to_virt(pg);
> + copy_page(l4tab, idle_pg_table);
> l4tab[0] = l4e_empty();
> l4tab[l4_table_offset(LINEAR_PT_VIRT_START)] =
> l4e_from_page(pg, __PAGE_HYPERVISOR);
> Index: 2008-10-27/xen/arch/x86/domain_build.c
> ===================================================================
> --- 2008-10-27.orig/xen/arch/x86/domain_build.c
> 2008-11-11 16:19:45.000000000 +0100
> +++ 2008-10-27/xen/arch/x86/domain_build.c 2008-11-11
> 16:18:36.000000000 +0100
> @@ -467,8 +467,9 @@ int __init construct_dom0(
> /* WARNING: The new domain must have its 'processor'
> field filled in! */
> l3start = l3tab = (l3_pgentry_t *)mpt_alloc; mpt_alloc
> += PAGE_SIZE;
> l2start = l2tab = (l2_pgentry_t *)mpt_alloc; mpt_alloc
> += 4*PAGE_SIZE;
> - memcpy(l2tab, idle_pg_table_l2, 4*PAGE_SIZE);
> - for (i = 0; i < 4; i++) {
> + for (i = 0; i < L3_PAGETABLE_ENTRIES; i++) {
> + copy_page(l2tab + i * L2_PAGETABLE_ENTRIES,
> + idle_pg_table_l2 + i * L2_PAGETABLE_ENTRIES);
> l3tab[i] = l3e_from_paddr((u32)l2tab + i*PAGE_SIZE, L3_PROT);
> l2tab[(LINEAR_PT_VIRT_START >> L2_PAGETABLE_SHIFT)+i] =
> l2e_from_paddr((u32)l2tab + i*PAGE_SIZE,
> __PAGE_HYPERVISOR);
> Index: 2008-10-27/xen/include/asm-x86/page.h
> ===================================================================
> --- 2008-10-27.orig/xen/include/asm-x86/page.h
> 2008-11-11 16:19:45.000000000 +0100
> +++ 2008-10-27/xen/include/asm-x86/page.h 2008-11-11
> 16:18:36.000000000 +0100
> @@ -215,7 +215,10 @@ void clear_page_sse2(void *);
> #define clear_page(_p) (cpu_has_xmm2 ?
> \
> clear_page_sse2((void *)(_p)) :
> \
> (void)memset((void *)(_p), 0,
> PAGE_SIZE))
> -#define copy_page(_t,_f) memcpy((void *)(_t), (void
> *)(_f), PAGE_SIZE)
> +void copy_page_sse2(void *, const void *);
> +#define copy_page(_t,_f) (cpu_has_xmm2 ?
> \
> + copy_page_sse2(_t, _f) :
> \
> + (void)memcpy(_t, _f, PAGE_SIZE))
>
> #define mfn_valid(mfn) ((mfn) < max_page)
>
>
>
>
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>
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