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>
65 lines
1.4 KiB
NASM
65 lines
1.4 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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; SetMem64.nasm
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;
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; Abstract:
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;
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; SetMem64 function
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;
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; Notes:
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;
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;------------------------------------------------------------------------------
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DEFAULT REL
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SECTION .text
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;------------------------------------------------------------------------------
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; VOID *
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; InternalMemSetMem64 (
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; IN VOID *Buffer,
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; IN UINTN Count,
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; IN UINT64 Value
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; )
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;------------------------------------------------------------------------------
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global ASM_PFX(InternalMemSetMem64)
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ASM_PFX(InternalMemSetMem64):
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mov rax, rcx ; rax <- Buffer
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xchg rcx, rdx ; rcx <- Count & rdx <- Buffer
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test dl, 8
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movq xmm0, r8
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jz .0
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mov [rdx], r8
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add rdx, 8
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dec rcx
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.0:
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push rbx
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mov rbx, rcx
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and rbx, 7
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shr rcx, 3
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jz @SetQwords
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movlhps xmm0, xmm0
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.1:
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movntdq [rdx], xmm0
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movntdq [rdx + 16], xmm0
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movntdq [rdx + 32], xmm0
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movntdq [rdx + 48], xmm0
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lea rdx, [rdx + 64]
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loop .1
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mfence
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@SetQwords:
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push rdi
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mov rcx, rbx
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mov rax, r8
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mov rdi, rdx
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rep stosq
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pop rdi
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.2:
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pop rbx
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ret
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