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Re: BufferPainter::Clear() optimization [message #53758 is a reply to message #53757]

Tue, 28 April 2020 10:20

mirek
Messages: 14261
Registered: November 2005

Ultimate Member

Current Fill(RGBA * assembler code

4000EEE0  cmp r8d,byte +0x10 
4000EEE4  jl 0x14000ef13 
4000EEE6  movd xmm0,edx 
4000EEEA  pshufd xmm0,xmm0,0x0 
4000EEEF  nop 
4000EEF0  mov eax,r8d 
4000EEF3  movdqu [rcx],xmm0 
4000EEF7  movdqu [rcx+0x10],xmm0 
4000EEFC  movdqu [rcx+0x20],xmm0 
4000EF01  movdqu [rcx+0x30],xmm0 
4000EF06  add rcx,byte +0x40 
4000EF0A  lea r8d,[rax-0x10] 
4000EF0E  cmp eax,byte +0x1f 
4000EF11  jg 0x14000eef0 
4000EF13  add r8d,byte -0x1 
4000EF17  cmp r8d,byte +0xe 
4000EF1B  ja 0x14000ef59 
4000EF1D  lea r9,[rel 0x4000ef5c] 
4000EF24  movsxd rax,dword [r9+r8*4] 
4000EF28  add rax,r9 
4000EF2B  jmp rax 
4000EF2D  mov [rcx+0x38],edx 
4000EF30  mov [rcx+0x34],edx 
4000EF33  mov [rcx+0x30],edx 
4000EF36  mov [rcx+0x2c],edx 
4000EF39  mov [rcx+0x28],edx 
4000EF3C  mov [rcx+0x24],edx 
4000EF3F  mov [rcx+0x20],edx 
4000EF42  mov [rcx+0x1c],edx 
4000EF45  mov [rcx+0x18],edx 
4000EF48  mov [rcx+0x14],edx 
4000EF4B  mov [rcx+0x10],edx 
4000EF4E  mov [rcx+0xc],edx 
4000EF51  mov [rcx+0x8],edx 
4000EF54  mov [rcx+0x4],edx 
4000EF57  mov [rcx],edx 
4000EF59  ret

and the central snippet from the memsetd variant....

40001565  movaps xmm0,[rel 0x402c60a0] 
4000156C  nop dword [rax+0x0] 
40001570  movups [rsi+rdx*4],xmm0 
40001574  movups [rsi+rdx*4+0x10],xmm0 
40001579  movups [rsi+rdx*4+0x20],xmm0 
4000157E  movups [rsi+rdx*4+0x30],xmm0 
40001583  movups [rsi+rdx*4+0x40],xmm0 
40001588  movups [rsi+rdx*4+0x50],xmm0 
4000158D  movups [rsi+rdx*4+0x60],xmm0 
40001592  movups [rsi+rdx*4+0x70],xmm0 
40001597  movups [rsi+rdx*4+0x80],xmm0 
4000159F  movups [rsi+rdx*4+0x90],xmm0 
400015A7  movups [rsi+rdx*4+0xa0],xmm0 
400015AF  movups [rsi+rdx*4+0xb0],xmm0 
400015B7  movups [rsi+rdx*4+0xc0],xmm0 
400015BF  movups [rsi+rdx*4+0xd0],xmm0 
400015C7  movups [rsi+rdx*4+0xe0],xmm0 
400015CF  movups [rsi+rdx*4+0xf0],xmm0 
400015D7  add rdx,byte +0x40 
400015DB  add rdi,byte +0x8 
400015DF  jnz 0x140001570

Interesting...

Benchmarking code

#include <CtrlLib/CtrlLib.h>

using namespace Upp;

GUI_APP_MAIN
{
	Color c = Red();
	
	int len = 4000 * 2000;
	
	Buffer<RGBA> b(len);

	for(int i = 0; i < 1000; i++) {
		{
			RTIMING("memsetd");
			memsetd(b, *(dword*)&(c), len);
		}
		{
			RTIMING("Fill");
			Fill(b, c, len);
		}
	}
}

CLANGx64, 2700x

TIMING Fill : 2.73 s - 2.73 ms ( 2.73 s / 1000 ), min: 2.00 ms, max: 4.00 ms, nesting: 0 - 1000
TIMING memsetd : 2.78 s - 2.78 ms ( 2.78 s / 1000 ), min: 2.00 ms, max: 5.00 ms, nesting: 0 - 1000

MSBT19x64

TIMING Fill : 2.89 s - 2.89 ms ( 2.89 s / 1000 ), min: 2.00 ms, max: 5.00 ms, nesting: 0 - 1000
TIMING memsetd : 2.90 s - 2.90 ms ( 2.90 s / 1000 ), min: 2.00 ms, max: 5.00 ms, nesting: 0 - 1000

[Updated on: Tue, 28 April 2020 10:31]

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