From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 7844) id BEBD33858285; Wed, 9 Nov 2022 04:33:43 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org BEBD33858285 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1667968423; bh=XBnNvV5o/ggaZ2HUzb4fl2EKEpM/6aiUz27pLUZZ+6Q=; h=From:To:Subject:Date:From; b=TnNC1klRoZSk8eQydGDf+M7ISV5jynEzkUuN2lmvLt1ZFrdJc4zYWL8MiLG9lCSPv LVQX2j77bd1nPTwnUM8fGXiTGjqbUySMg849uQVgqEDu4rSNzaX12ok0wsGBw7YEhW /CCBNI4Pw6Xyqq5gSSxU1VLf2Ckxyhq9T0ySPbT8= Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Noah Goldstein To: glibc-cvs@sourceware.org Subject: [glibc] x86: Use VMM API in memcmp-evex-movbe.S and minor changes X-Act-Checkin: glibc X-Git-Author: Noah Goldstein X-Git-Refname: refs/heads/master X-Git-Oldrev: ca7d181b62f703ae56b7be1e27428184560f68b4 X-Git-Newrev: 419c832aba43276e285586998261d1db06033193 Message-Id: <20221109043343.BEBD33858285@sourceware.org> Date: Wed, 9 Nov 2022 04:33:43 +0000 (GMT) List-Id: https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=419c832aba43276e285586998261d1db06033193 commit 419c832aba43276e285586998261d1db06033193 Author: Noah Goldstein Date: Sat Oct 29 15:19:58 2022 -0500 x86: Use VMM API in memcmp-evex-movbe.S and minor changes The only change to the existing generated code is `tzcnt` -> `bsf` to save a byte of code size here and there. Rewriting with VMM API allows for memcmp-evex-movbe to be used with evex512 by including "x86-evex512-vecs.h" at the top. Complete check passes on x86-64. Diff: --- sysdeps/x86_64/multiarch/memcmp-evex-movbe.S | 308 +++++++++++++++------------ 1 file changed, 175 insertions(+), 133 deletions(-) diff --git a/sysdeps/x86_64/multiarch/memcmp-evex-movbe.S b/sysdeps/x86_64/multiarch/memcmp-evex-movbe.S index bc017768be..f6c379831e 100644 --- a/sysdeps/x86_64/multiarch/memcmp-evex-movbe.S +++ b/sysdeps/x86_64/multiarch/memcmp-evex-movbe.S @@ -62,44 +62,38 @@ Latency: # define MEMCMP __memcmp_evex_movbe # endif -# define VMOVU vmovdqu64 +# ifndef VEC_SIZE +# include "x86-evex256-vecs.h" +# endif # ifdef USE_AS_WMEMCMP # define VMOVU_MASK vmovdqu32 # define CHAR_SIZE 4 # define VPCMP vpcmpd +# define VPCMPEQ vpcmpeqd # define VPTEST vptestmd + +# define USE_WIDE_CHAR # else # define VMOVU_MASK vmovdqu8 # define CHAR_SIZE 1 # define VPCMP vpcmpub +# define VPCMPEQ vpcmpeqb # define VPTEST vptestmb # endif +# include "reg-macros.h" -# define VEC_SIZE 32 # define PAGE_SIZE 4096 # define CHAR_PER_VEC (VEC_SIZE / CHAR_SIZE) -# define XMM0 xmm16 -# define XMM1 xmm17 -# define XMM2 xmm18 -# define YMM0 ymm16 -# define XMM1 xmm17 -# define XMM2 xmm18 -# define YMM1 ymm17 -# define YMM2 ymm18 -# define YMM3 ymm19 -# define YMM4 ymm20 -# define YMM5 ymm21 -# define YMM6 ymm22 /* Warning! wmemcmp has to use SIGNED comparison for elements. memcmp has to use UNSIGNED comparison for elemnts. */ - .section .text.evex,"ax",@progbits + .section SECTION(.text), "ax", @progbits /* Cache align memcmp entry. This allows for much more thorough frontend optimization. */ ENTRY_P2ALIGN (MEMCMP, 6) @@ -111,23 +105,40 @@ ENTRY_P2ALIGN (MEMCMP, 6) /* Fall through for [0, VEC_SIZE] as its the hottest. */ ja L(more_1x_vec) - /* Create mask for CHAR's we want to compare. This allows us to - avoid having to include page cross logic. */ - movl $-1, %ecx - bzhil %edx, %ecx, %ecx - kmovd %ecx, %k2 + /* Create mask of bytes that are guranteed to be valid because + of length (edx). Using masked movs allows us to skip checks + for page crosses/zero size. */ + mov $-1, %VRAX + bzhi %VRDX, %VRAX, %VRAX + /* NB: A `jz` might be useful here. Page-faults that are + invalidated by predicate execution (the evex mask) can be + very slow. The expectation is this is not the norm so and + "most" code will not regularly call 'memcmp' with length = 0 + and memory that is not wired up. */ + KMOV %VRAX, %k2 + + /* Safe to load full ymm with mask. */ - VMOVU_MASK (%rsi), %YMM2{%k2} - VPCMP $4,(%rdi), %YMM2, %k1{%k2} - kmovd %k1, %eax - testl %eax, %eax + VMOVU_MASK (%rsi), %VMM(2){%k2}{z} + /* Slightly different method for VEC_SIZE == 64 to save a bit of + code size. This allows us to fit L(return_vec_0) entirely in + the first cache line. */ +# if VEC_SIZE == 64 + VPCMPEQ (%rdi), %VMM(2), %k1{%k2} + KMOV %k1, %VRCX + sub %VRCX, %VRAX +# else + VPCMP $4, (%rdi), %VMM(2), %k1{%k2} + KMOV %k1, %VRAX + test %VRAX, %VRAX +# endif jnz L(return_vec_0) ret - .p2align 4 + .p2align 4,, 11 L(return_vec_0): - tzcntl %eax, %eax + bsf %VRAX, %VRAX # ifdef USE_AS_WMEMCMP movl (%rdi, %rax, CHAR_SIZE), %ecx xorl %edx, %edx @@ -138,33 +149,36 @@ L(return_vec_0): leal -1(%rdx, %rdx), %eax # else movzbl (%rsi, %rax), %ecx +# if VEC_SIZE == 64 + movb (%rdi, %rax), %al +# else movzbl (%rdi, %rax), %eax +# endif subl %ecx, %eax # endif ret - - .p2align 4 + .p2align 4,, 11 L(more_1x_vec): /* From VEC to 2 * VEC. No branch when size == VEC_SIZE. */ - VMOVU (%rsi), %YMM1 + VMOVU (%rsi), %VMM(1) /* Use compare not equals to directly check for mismatch. */ - VPCMP $4,(%rdi), %YMM1, %k1 - kmovd %k1, %eax + VPCMP $4, (%rdi), %VMM(1), %k1 + KMOV %k1, %VRAX /* NB: eax must be destination register if going to - L(return_vec_[0,2]). For L(return_vec_3) destination register - must be ecx. */ - testl %eax, %eax + L(return_vec_[0,2]). For L(return_vec_3) destination + register must be ecx. */ + test %VRAX, %VRAX jnz L(return_vec_0) cmpq $(CHAR_PER_VEC * 2), %rdx jbe L(last_1x_vec) /* Check second VEC no matter what. */ - VMOVU VEC_SIZE(%rsi), %YMM2 - VPCMP $4, VEC_SIZE(%rdi), %YMM2, %k1 - kmovd %k1, %eax - testl %eax, %eax + VMOVU VEC_SIZE(%rsi), %VMM(2) + VPCMP $4, VEC_SIZE(%rdi), %VMM(2), %k1 + KMOV %k1, %VRAX + test %VRAX, %VRAX jnz L(return_vec_1) /* Less than 4 * VEC. */ @@ -172,16 +186,16 @@ L(more_1x_vec): jbe L(last_2x_vec) /* Check third and fourth VEC no matter what. */ - VMOVU (VEC_SIZE * 2)(%rsi), %YMM3 - VPCMP $4,(VEC_SIZE * 2)(%rdi), %YMM3, %k1 - kmovd %k1, %eax - testl %eax, %eax + VMOVU (VEC_SIZE * 2)(%rsi), %VMM(3) + VPCMP $4, (VEC_SIZE * 2)(%rdi), %VMM(3), %k1 + KMOV %k1, %VRAX + test %VRAX, %VRAX jnz L(return_vec_2) - VMOVU (VEC_SIZE * 3)(%rsi), %YMM4 - VPCMP $4,(VEC_SIZE * 3)(%rdi), %YMM4, %k1 - kmovd %k1, %ecx - testl %ecx, %ecx + VMOVU (VEC_SIZE * 3)(%rsi), %VMM(4) + VPCMP $4, (VEC_SIZE * 3)(%rdi), %VMM(4), %k1 + KMOV %k1, %VRCX + test %VRCX, %VRCX jnz L(return_vec_3) /* Go to 4x VEC loop. */ @@ -192,8 +206,8 @@ L(more_1x_vec): branches. */ /* Load first two VEC from s2 before adjusting addresses. */ - VMOVU -(VEC_SIZE * 4)(%rsi, %rdx, CHAR_SIZE), %YMM1 - VMOVU -(VEC_SIZE * 3)(%rsi, %rdx, CHAR_SIZE), %YMM2 + VMOVU -(VEC_SIZE * 4)(%rsi, %rdx, CHAR_SIZE), %VMM(1) + VMOVU -(VEC_SIZE * 3)(%rsi, %rdx, CHAR_SIZE), %VMM(2) leaq -(4 * VEC_SIZE)(%rdi, %rdx, CHAR_SIZE), %rdi leaq -(4 * VEC_SIZE)(%rsi, %rdx, CHAR_SIZE), %rsi @@ -202,56 +216,61 @@ L(more_1x_vec): /* vpxor will be all 0s if s1 and s2 are equal. Otherwise it will have some 1s. */ - vpxorq (%rdi), %YMM1, %YMM1 - vpxorq (VEC_SIZE)(%rdi), %YMM2, %YMM2 + vpxorq (%rdi), %VMM(1), %VMM(1) + vpxorq (VEC_SIZE)(%rdi), %VMM(2), %VMM(2) - VMOVU (VEC_SIZE * 2)(%rsi), %YMM3 - vpxorq (VEC_SIZE * 2)(%rdi), %YMM3, %YMM3 + VMOVU (VEC_SIZE * 2)(%rsi), %VMM(3) + vpxorq (VEC_SIZE * 2)(%rdi), %VMM(3), %VMM(3) - VMOVU (VEC_SIZE * 3)(%rsi), %YMM4 - /* Ternary logic to xor (VEC_SIZE * 3)(%rdi) with YMM4 while - oring with YMM1. Result is stored in YMM4. */ - vpternlogd $0xde,(VEC_SIZE * 3)(%rdi), %YMM1, %YMM4 + VMOVU (VEC_SIZE * 3)(%rsi), %VMM(4) + /* Ternary logic to xor (VEC_SIZE * 3)(%rdi) with VEC(4) while + oring with VEC(1). Result is stored in VEC(4). */ + vpternlogd $0xde, (VEC_SIZE * 3)(%rdi), %VMM(1), %VMM(4) - /* Or together YMM2, YMM3, and YMM4 into YMM4. */ - vpternlogd $0xfe, %YMM2, %YMM3, %YMM4 + /* Or together VEC(2), VEC(3), and VEC(4) into VEC(4). */ + vpternlogd $0xfe, %VMM(2), %VMM(3), %VMM(4) - /* Test YMM4 against itself. Store any CHAR mismatches in k1. + /* Test VEC(4) against itself. Store any CHAR mismatches in k1. */ - VPTEST %YMM4, %YMM4, %k1 + VPTEST %VMM(4), %VMM(4), %k1 /* k1 must go to ecx for L(return_vec_0_1_2_3). */ - kmovd %k1, %ecx - testl %ecx, %ecx + KMOV %k1, %VRCX + test %VRCX, %VRCX jnz L(return_vec_0_1_2_3) /* NB: eax must be zero to reach here. */ ret - .p2align 4,, 8 + .p2align 4,, 9 L(8x_end_return_vec_0_1_2_3): movq %rdx, %rdi L(8x_return_vec_0_1_2_3): + /* L(loop_4x_vec) leaves result in `k1` for VEC_SIZE == 64. */ +# if VEC_SIZE == 64 + KMOV %k1, %VRCX +# endif addq %rdi, %rsi L(return_vec_0_1_2_3): - VPTEST %YMM1, %YMM1, %k0 - kmovd %k0, %eax - testl %eax, %eax + VPTEST %VMM(1), %VMM(1), %k0 + KMOV %k0, %VRAX + test %VRAX, %VRAX jnz L(return_vec_0) - VPTEST %YMM2, %YMM2, %k0 - kmovd %k0, %eax - testl %eax, %eax + VPTEST %VMM(2), %VMM(2), %k0 + KMOV %k0, %VRAX + test %VRAX, %VRAX jnz L(return_vec_1) - VPTEST %YMM3, %YMM3, %k0 - kmovd %k0, %eax - testl %eax, %eax + VPTEST %VMM(3), %VMM(3), %k0 + KMOV %k0, %VRAX + test %VRAX, %VRAX jnz L(return_vec_2) + .p2align 4,, 2 L(return_vec_3): /* bsf saves 1 byte from tzcnt. This keep L(return_vec_3) in one fetch block and the entire L(*return_vec_0_1_2_3) in 1 cache line. */ - bsfl %ecx, %ecx + bsf %VRCX, %VRCX # ifdef USE_AS_WMEMCMP movl (VEC_SIZE * 3)(%rdi, %rcx, CHAR_SIZE), %eax xorl %edx, %edx @@ -266,11 +285,11 @@ L(return_vec_3): ret - .p2align 4 + .p2align 4,, 8 L(return_vec_1): /* bsf saves 1 byte over tzcnt and keeps L(return_vec_1) in one fetch block. */ - bsfl %eax, %eax + bsf %VRAX, %VRAX # ifdef USE_AS_WMEMCMP movl VEC_SIZE(%rdi, %rax, CHAR_SIZE), %ecx xorl %edx, %edx @@ -284,11 +303,11 @@ L(return_vec_1): # endif ret - .p2align 4,, 10 + .p2align 4,, 7 L(return_vec_2): /* bsf saves 1 byte over tzcnt and keeps L(return_vec_2) in one fetch block. */ - bsfl %eax, %eax + bsf %VRAX, %VRAX # ifdef USE_AS_WMEMCMP movl (VEC_SIZE * 2)(%rdi, %rax, CHAR_SIZE), %ecx xorl %edx, %edx @@ -302,7 +321,7 @@ L(return_vec_2): # endif ret - .p2align 4 + .p2align 4,, 8 L(more_8x_vec): /* Set end of s1 in rdx. */ leaq -(VEC_SIZE * 4)(%rdi, %rdx, CHAR_SIZE), %rdx @@ -316,62 +335,82 @@ L(more_8x_vec): .p2align 4 L(loop_4x_vec): - VMOVU (%rsi, %rdi), %YMM1 - vpxorq (%rdi), %YMM1, %YMM1 - VMOVU VEC_SIZE(%rsi, %rdi), %YMM2 - vpxorq VEC_SIZE(%rdi), %YMM2, %YMM2 - VMOVU (VEC_SIZE * 2)(%rsi, %rdi), %YMM3 - vpxorq (VEC_SIZE * 2)(%rdi), %YMM3, %YMM3 - VMOVU (VEC_SIZE * 3)(%rsi, %rdi), %YMM4 - vpternlogd $0xde,(VEC_SIZE * 3)(%rdi), %YMM1, %YMM4 - vpternlogd $0xfe, %YMM2, %YMM3, %YMM4 - VPTEST %YMM4, %YMM4, %k1 - kmovd %k1, %ecx - testl %ecx, %ecx + VMOVU (%rsi, %rdi), %VMM(1) + vpxorq (%rdi), %VMM(1), %VMM(1) + VMOVU VEC_SIZE(%rsi, %rdi), %VMM(2) + vpxorq VEC_SIZE(%rdi), %VMM(2), %VMM(2) + VMOVU (VEC_SIZE * 2)(%rsi, %rdi), %VMM(3) + vpxorq (VEC_SIZE * 2)(%rdi), %VMM(3), %VMM(3) + VMOVU (VEC_SIZE * 3)(%rsi, %rdi), %VMM(4) + vpternlogd $0xde, (VEC_SIZE * 3)(%rdi), %VMM(1), %VMM(4) + vpternlogd $0xfe, %VMM(2), %VMM(3), %VMM(4) + VPTEST %VMM(4), %VMM(4), %k1 + /* If VEC_SIZE == 64 just branch with KTEST. We have free port0 + space and it allows the loop to fit in 2x cache lines + instead of 3. */ +# if VEC_SIZE == 64 + KTEST %k1, %k1 +# else + KMOV %k1, %VRCX + test %VRCX, %VRCX +# endif jnz L(8x_return_vec_0_1_2_3) subq $-(VEC_SIZE * 4), %rdi cmpq %rdx, %rdi jb L(loop_4x_vec) - subq %rdx, %rdi /* rdi has 4 * VEC_SIZE - remaining length. */ cmpl $(VEC_SIZE * 3), %edi - jae L(8x_last_1x_vec) + jge L(8x_last_1x_vec) /* Load regardless of branch. */ - VMOVU (VEC_SIZE * 2)(%rsi, %rdx), %YMM3 - cmpl $(VEC_SIZE * 2), %edi - jae L(8x_last_2x_vec) + VMOVU (VEC_SIZE * 2)(%rsi, %rdx), %VMM(3) - vpxorq (VEC_SIZE * 2)(%rdx), %YMM3, %YMM3 - - VMOVU (%rsi, %rdx), %YMM1 - vpxorq (%rdx), %YMM1, %YMM1 + /* Seperate logic as we can only use testb for VEC_SIZE == 64. + */ +# if VEC_SIZE == 64 + testb %dil, %dil + js L(8x_last_2x_vec) +# else + cmpl $(VEC_SIZE * 2), %edi + jge L(8x_last_2x_vec) +# endif - VMOVU VEC_SIZE(%rsi, %rdx), %YMM2 - vpxorq VEC_SIZE(%rdx), %YMM2, %YMM2 - VMOVU (VEC_SIZE * 3)(%rsi, %rdx), %YMM4 - vpternlogd $0xde,(VEC_SIZE * 3)(%rdx), %YMM1, %YMM4 - vpternlogd $0xfe, %YMM2, %YMM3, %YMM4 - VPTEST %YMM4, %YMM4, %k1 - kmovd %k1, %ecx - testl %ecx, %ecx + vpxorq (VEC_SIZE * 2)(%rdx), %VMM(3), %VMM(3) + + VMOVU (%rsi, %rdx), %VMM(1) + vpxorq (%rdx), %VMM(1), %VMM(1) + + VMOVU VEC_SIZE(%rsi, %rdx), %VMM(2) + vpxorq VEC_SIZE(%rdx), %VMM(2), %VMM(2) + VMOVU (VEC_SIZE * 3)(%rsi, %rdx), %VMM(4) + vpternlogd $0xde, (VEC_SIZE * 3)(%rdx), %VMM(1), %VMM(4) + vpternlogd $0xfe, %VMM(2), %VMM(3), %VMM(4) + VPTEST %VMM(4), %VMM(4), %k1 + /* L(8x_end_return_vec_0_1_2_3) expects bitmask to still be in + `k1` if VEC_SIZE == 64. */ +# if VEC_SIZE == 64 + KTEST %k1, %k1 +# else + KMOV %k1, %VRCX + test %VRCX, %VRCX +# endif jnz L(8x_end_return_vec_0_1_2_3) /* NB: eax must be zero to reach here. */ ret /* Only entry is from L(more_8x_vec). */ - .p2align 4,, 10 + .p2align 4,, 6 L(8x_last_2x_vec): - VPCMP $4,(VEC_SIZE * 2)(%rdx), %YMM3, %k1 - kmovd %k1, %eax - testl %eax, %eax + VPCMP $4, (VEC_SIZE * 2)(%rdx), %VMM(3), %k1 + KMOV %k1, %VRAX + test %VRAX, %VRAX jnz L(8x_return_vec_2) - /* Naturally aligned to 16 bytes. */ + .p2align 4,, 5 L(8x_last_1x_vec): - VMOVU (VEC_SIZE * 3)(%rsi, %rdx), %YMM1 - VPCMP $4,(VEC_SIZE * 3)(%rdx), %YMM1, %k1 - kmovd %k1, %eax - testl %eax, %eax + VMOVU (VEC_SIZE * 3)(%rsi, %rdx), %VMM(1) + VPCMP $4, (VEC_SIZE * 3)(%rdx), %VMM(1), %k1 + KMOV %k1, %VRAX + test %VRAX, %VRAX jnz L(8x_return_vec_3) ret @@ -383,7 +422,7 @@ L(8x_last_1x_vec): L(8x_return_vec_2): subq $VEC_SIZE, %rdx L(8x_return_vec_3): - bsfl %eax, %eax + bsf %VRAX, %VRAX # ifdef USE_AS_WMEMCMP leaq (%rdx, %rax, CHAR_SIZE), %rax movl (VEC_SIZE * 3)(%rax), %ecx @@ -399,32 +438,34 @@ L(8x_return_vec_3): # endif ret - .p2align 4,, 10 + .p2align 4,, 8 L(last_2x_vec): /* Check second to last VEC. */ - VMOVU -(VEC_SIZE * 2)(%rsi, %rdx, CHAR_SIZE), %YMM1 - VPCMP $4, -(VEC_SIZE * 2)(%rdi, %rdx, CHAR_SIZE), %YMM1, %k1 - kmovd %k1, %eax - testl %eax, %eax + VMOVU -(VEC_SIZE * 2)(%rsi, %rdx, CHAR_SIZE), %VMM(1) + VPCMP $4, -(VEC_SIZE * 2)(%rdi, %rdx, CHAR_SIZE), %VMM(1), %k1 + KMOV %k1, %VRAX + test %VRAX, %VRAX jnz L(return_vec_1_end) /* Check last VEC. */ - .p2align 4 + .p2align 4,, 8 L(last_1x_vec): - VMOVU -(VEC_SIZE * 1)(%rsi, %rdx, CHAR_SIZE), %YMM1 - VPCMP $4, -(VEC_SIZE * 1)(%rdi, %rdx, CHAR_SIZE), %YMM1, %k1 - kmovd %k1, %eax - testl %eax, %eax + VMOVU -(VEC_SIZE * 1)(%rsi, %rdx, CHAR_SIZE), %VMM(1) + VPCMP $4, -(VEC_SIZE * 1)(%rdi, %rdx, CHAR_SIZE), %VMM(1), %k1 + KMOV %k1, %VRAX + test %VRAX, %VRAX jnz L(return_vec_0_end) ret - /* Don't align. Takes 2-fetch blocks either way and aligning - will cause code to spill into another cacheline. */ + /* Don't fully align. Takes 2-fetch blocks either way and + aligning will cause code to spill into another cacheline. + */ + .p2align 4,, 3 L(return_vec_1_end): /* Use bsf to save code size. This is necessary to have L(one_or_less) fit in aligning bytes between. */ - bsfl %eax, %eax + bsf %VRAX, %VRAX addl %edx, %eax # ifdef USE_AS_WMEMCMP movl -(VEC_SIZE * 2)(%rdi, %rax, CHAR_SIZE), %ecx @@ -439,10 +480,11 @@ L(return_vec_1_end): # endif ret + .p2align 4,, 2 /* Don't align. Takes 2-fetch blocks either way and aligning will cause code to spill into another cacheline. */ L(return_vec_0_end): - tzcntl %eax, %eax + bsf %VRAX, %VRAX addl %edx, %eax # ifdef USE_AS_WMEMCMP movl -VEC_SIZE(%rdi, %rax, CHAR_SIZE), %ecx @@ -456,7 +498,7 @@ L(return_vec_0_end): subl %ecx, %eax # endif ret - /* 1-byte until next cache line. */ - + /* evex256: 2-byte until next cache line. evex512: 46-bytes + until next cache line. */ END (MEMCMP) #endif