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		d25fd8710d
		
	
	
	
	
		
			
			The current SSE2 implementation of the ZeroMem(), SetMem(), SetMem16(), SetMem32 and SetMem64 functions is writing 16 bytes per 16 bytes. It hurts the performances so bad that this is even slower than a simple 'rep stos' (4% slower) in regular DRAM. To take full advantages of the 'movntdq' instruction it is better to "queue" a total of 64 bytes in the write combining buffers. This patch implement such a change. Below is a table where I measured (with 'rdtsc') the time to write an entire 100MB RAM buffer. These functions operate almost two times faster. | Function | Arch | Untouched | 64 bytes | Result | |----------+------+-----------+----------+--------| | ZeroMem | Ia32 | 17765947 | 9136062 | 1.945x | | ZeroMem | X64 | 17525170 | 9233391 | 1.898x | | SetMem | Ia32 | 17522291 | 9137272 | 1.918x | | SetMem | X64 | 17949261 | 9176978 | 1.956x | | SetMem16 | Ia32 | 18219673 | 9372062 | 1.944x | | SetMem16 | X64 | 17523331 | 9275184 | 1.889x | | SetMem32 | Ia32 | 18495036 | 9273053 | 1.994x | | SetMem32 | X64 | 17368864 | 9285885 | 1.870x | | SetMem64 | Ia32 | 18564473 | 9241362 | 2.009x | | SetMem64 | X64 | 17506951 | 9280148 | 1.886x | Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com> Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>
		
			
				
	
	
		
			71 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			NASM
		
	
	
	
	
	
			
		
		
	
	
			71 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			NASM
		
	
	
	
	
	
| ;------------------------------------------------------------------------------
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| ;
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| ; Copyright (c) 2006, Intel Corporation. All rights reserved.<BR>
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| ; SPDX-License-Identifier: BSD-2-Clause-Patent
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| ;
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| ; Module Name:
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| ;
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| ;   SetMem.nasm
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| ;
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| ; Abstract:
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| ;
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| ;   SetMem function
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| ;
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| ; Notes:
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| ;
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| ;------------------------------------------------------------------------------
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| 
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|     SECTION .text
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| 
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| ;------------------------------------------------------------------------------
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| ;  VOID *
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| ;  EFIAPI
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| ;  InternalMemSetMem (
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| ;    IN VOID   *Buffer,
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| ;    IN UINTN  Count,
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| ;    IN UINT8  Value
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| ;    );
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| ;------------------------------------------------------------------------------
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| global ASM_PFX(InternalMemSetMem)
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| ASM_PFX(InternalMemSetMem):
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|     push    edi
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|     mov     edx, [esp + 12]             ; edx <- Count
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|     mov     edi, [esp + 8]              ; edi <- Buffer
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|     mov     al, [esp + 16]              ; al <- Value
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|     xor     ecx, ecx
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|     sub     ecx, edi
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|     and     ecx, 63                     ; ecx + edi aligns on 16-byte boundary
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|     jz      .0
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|     cmp     ecx, edx
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|     cmova   ecx, edx
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|     sub     edx, ecx
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|     rep     stosb
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| .0:
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|     mov     ecx, edx
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|     and     edx, 63
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|     shr     ecx, 6                      ; ecx <- # of DQwords to set
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|     jz      @SetBytes
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|     mov     ah, al                      ; ax <- Value | (Value << 8)
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|     add     esp, -16
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|     movdqu  [esp], xmm0                 ; save xmm0
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|     movd    xmm0, eax
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|     pshuflw xmm0, xmm0, 0               ; xmm0[0..63] <- Value repeats 8 times
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|     movlhps xmm0, xmm0                  ; xmm0 <- Value repeats 16 times
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| .1:
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|     movntdq [edi], xmm0                 ; edi should be 16-byte aligned
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|     movntdq [edi + 16], xmm0
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|     movntdq [edi + 32], xmm0
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|     movntdq [edi + 48], xmm0
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|     add     edi, 64
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|     loop    .1
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|     mfence
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|     movdqu  xmm0, [esp]                 ; restore xmm0
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|     add     esp, 16                     ; stack cleanup
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| @SetBytes:
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|     mov     ecx, edx
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|     rep     stosb
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|     mov     eax, [esp + 8]              ; eax <- Buffer as return value
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|     pop     edi
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|     ret
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| 
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