From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-vs1-xe2f.google.com (mail-vs1-xe2f.google.com [IPv6:2607:f8b0:4864:20::e2f]) by sourceware.org (Postfix) with ESMTPS id 58FEC3839C6E; Thu, 12 May 2022 19:45:45 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 58FEC3839C6E Received: by mail-vs1-xe2f.google.com with SMTP id z144so6255095vsz.13; Thu, 12 May 2022 12:45:45 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=qhZKPPBWE4vJqghcoyC2cLcoM2WnsxDaHNczGLoPmjI=; b=xkRehLJ8BbiMwmxLGlkjnL3YrqdJPXA9wS46LlZjEPBJBgytBN6rpgxIghcfdqJX21 FqpYfsvKjucf1oOKHPvjaNa1Oh5dSmyvu3RhPG7pNmYG3+Aawejk5u8Ql06fp399Ie7x 3fNWlmmQxRRvmh1ad0x3C95hDxtV8UTzrHcdS83J1cfRA5wcGeOjalsuQKdnZY/3oS+e byNltVWWp1yZT0acm6OAeaeN49N9uBu4AjEADG1w2qHkx6uOL5QlMtj+3MzLWUy8dHy6 JmvtoioI8DE146vuzaz8juybG8eB5RP36ZVSQctMujuybCxZcVxS7MW3EWfPQVWCiQsz Rrew== X-Gm-Message-State: AOAM5336BAIEs47v07qm/PfBv666Jh/4t0q1EjtelmmpbApkrlpOx1lF BhV19hIA0SAPtoipCIRQLb2U2Mr9MRZVOF1wNOxtZFStUHY= X-Google-Smtp-Source: ABdhPJyGMGUJawkziDl9YtP7U0jAUGflXUA4/LgUhEdZeMmN2IZcoEx+SKpJwGH32ig7fz2yL5in92WrDzXdBTG695U= X-Received: by 2002:a67:ee4f:0:b0:32c:ee75:6e98 with SMTP id g15-20020a67ee4f000000b0032cee756e98mr863993vsp.79.1652384744760; Thu, 12 May 2022 12:45:44 -0700 (PDT) MIME-Version: 1.0 References: <20220323215734.3927131-1-goldstein.w.n@gmail.com> <20220323215734.3927131-18-goldstein.w.n@gmail.com> In-Reply-To: From: Sunil Pandey Date: Thu, 12 May 2022 12:45:08 -0700 Message-ID: Subject: Re: [PATCH v1 18/23] x86: Optimize str{n}casecmp TOLOWER logic in strcmp-sse42.S To: "H.J. Lu" , Libc-stable Mailing List Cc: Noah Goldstein , GNU C Library Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-7.4 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_ENVFROM_END_DIGIT, FREEMAIL_FROM, GIT_PATCH_0, HK_RANDOM_ENVFROM, HK_RANDOM_FROM, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: libc-stable@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-stable mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 12 May 2022 19:45:47 -0000 On Thu, Mar 24, 2022 at 12:05 PM H.J. Lu via Libc-alpha wrote: > > On Wed, Mar 23, 2022 at 3:02 PM Noah Goldstein wrote: > > > > Slightly faster method of doing TOLOWER that saves an > > instruction. > > > > Also replace the hard coded 5-byte no with .p2align 4. On builds with > > CET enabled this misaligned entry to strcasecmp. > > > > geometric_mean(N=40) of all benchmarks New / Original: .920 > > > > All string/memory tests pass. > > --- > > Geomtric Mean N=40 runs; All functions page aligned > > length, align1, align2, max_char, New Time / Old Time > > 1, 1, 1, 127, 0.914 > > 2, 2, 2, 127, 0.952 > > 3, 3, 3, 127, 0.924 > > 4, 4, 4, 127, 0.995 > > 5, 5, 5, 127, 0.985 > > 6, 6, 6, 127, 1.017 > > 7, 7, 7, 127, 1.031 > > 8, 0, 0, 127, 0.967 > > 9, 1, 1, 127, 0.969 > > 10, 2, 2, 127, 0.951 > > 11, 3, 3, 127, 0.938 > > 12, 4, 4, 127, 0.937 > > 13, 5, 5, 127, 0.967 > > 14, 6, 6, 127, 0.941 > > 15, 7, 7, 127, 0.951 > > 4, 0, 0, 127, 0.959 > > 4, 0, 0, 254, 0.98 > > 8, 0, 0, 254, 0.959 > > 16, 0, 0, 127, 0.895 > > 16, 0, 0, 254, 0.901 > > 32, 0, 0, 127, 0.85 > > 32, 0, 0, 254, 0.851 > > 64, 0, 0, 127, 0.897 > > 64, 0, 0, 254, 0.895 > > 128, 0, 0, 127, 0.944 > > 128, 0, 0, 254, 0.935 > > 256, 0, 0, 127, 0.922 > > 256, 0, 0, 254, 0.913 > > 512, 0, 0, 127, 0.921 > > 512, 0, 0, 254, 0.914 > > 1024, 0, 0, 127, 0.845 > > 1024, 0, 0, 254, 0.84 > > 16, 1, 2, 127, 0.923 > > 16, 2, 1, 254, 0.955 > > 32, 2, 4, 127, 0.979 > > 32, 4, 2, 254, 0.957 > > 64, 3, 6, 127, 0.866 > > 64, 6, 3, 254, 0.849 > > 128, 4, 0, 127, 0.882 > > 128, 0, 4, 254, 0.876 > > 256, 5, 2, 127, 0.877 > > 256, 2, 5, 254, 0.882 > > 512, 6, 4, 127, 0.822 > > 512, 4, 6, 254, 0.862 > > 1024, 7, 6, 127, 0.903 > > 1024, 6, 7, 254, 0.908 > > > > sysdeps/x86_64/multiarch/strcmp-sse42.S | 83 +++++++++++-------------- > > 1 file changed, 35 insertions(+), 48 deletions(-) > > > > diff --git a/sysdeps/x86_64/multiarch/strcmp-sse42.S b/sysdeps/x86_64/multiarch/strcmp-sse42.S > > index 580feb90e9..7805ae9d41 100644 > > --- a/sysdeps/x86_64/multiarch/strcmp-sse42.S > > +++ b/sysdeps/x86_64/multiarch/strcmp-sse42.S > > @@ -88,9 +88,8 @@ ENTRY (GLABEL(__strcasecmp)) > > movq __libc_tsd_LOCALE@gottpoff(%rip),%rax > > mov %fs:(%rax),%RDX_LP > > > > - // XXX 5 byte should be before the function > > - /* 5-byte NOP. */ > > - .byte 0x0f,0x1f,0x44,0x00,0x00 > > + /* Either 1 or 5 bytes (dependeing if CET is enabled). */ > > + .p2align 4 > > END (GLABEL(__strcasecmp)) > > /* FALLTHROUGH to strcasecmp_l. */ > > #endif > > @@ -99,9 +98,8 @@ ENTRY (GLABEL(__strncasecmp)) > > movq __libc_tsd_LOCALE@gottpoff(%rip),%rax > > mov %fs:(%rax),%RCX_LP > > > > - // XXX 5 byte should be before the function > > - /* 5-byte NOP. */ > > - .byte 0x0f,0x1f,0x44,0x00,0x00 > > + /* Either 1 or 5 bytes (dependeing if CET is enabled). */ > > + .p2align 4 > > END (GLABEL(__strncasecmp)) > > /* FALLTHROUGH to strncasecmp_l. */ > > #endif > > @@ -169,27 +167,22 @@ STRCMP_SSE42: > > #if defined USE_AS_STRCASECMP_L || defined USE_AS_STRNCASECMP_L > > .section .rodata.cst16,"aM",@progbits,16 > > .align 16 > > -LABEL(belowupper): > > - .quad 0x4040404040404040 > > - .quad 0x4040404040404040 > > -LABEL(topupper): > > -# ifdef USE_AVX > > - .quad 0x5a5a5a5a5a5a5a5a > > - .quad 0x5a5a5a5a5a5a5a5a > > -# else > > - .quad 0x5b5b5b5b5b5b5b5b > > - .quad 0x5b5b5b5b5b5b5b5b > > -# endif > > -LABEL(touppermask): > > +LABEL(lcase_min): > > + .quad 0x3f3f3f3f3f3f3f3f > > + .quad 0x3f3f3f3f3f3f3f3f > > +LABEL(lcase_max): > > + .quad 0x9999999999999999 > > + .quad 0x9999999999999999 > > +LABEL(case_add): > > .quad 0x2020202020202020 > > .quad 0x2020202020202020 > > .previous > > - movdqa LABEL(belowupper)(%rip), %xmm4 > > -# define UCLOW_reg %xmm4 > > - movdqa LABEL(topupper)(%rip), %xmm5 > > -# define UCHIGH_reg %xmm5 > > - movdqa LABEL(touppermask)(%rip), %xmm6 > > -# define LCQWORD_reg %xmm6 > > + movdqa LABEL(lcase_min)(%rip), %xmm4 > > +# define LCASE_MIN_reg %xmm4 > > + movdqa LABEL(lcase_max)(%rip), %xmm5 > > +# define LCASE_MAX_reg %xmm5 > > + movdqa LABEL(case_add)(%rip), %xmm6 > > +# define CASE_ADD_reg %xmm6 > > #endif > > cmp $0x30, %ecx > > ja LABEL(crosscache)/* rsi: 16-byte load will cross cache line */ > > @@ -200,32 +193,26 @@ LABEL(touppermask): > > #if defined USE_AS_STRCASECMP_L || defined USE_AS_STRNCASECMP_L > > # ifdef USE_AVX > > # define TOLOWER(reg1, reg2) \ > > - vpcmpgtb UCLOW_reg, reg1, %xmm7; \ > > - vpcmpgtb UCHIGH_reg, reg1, %xmm8; \ > > - vpcmpgtb UCLOW_reg, reg2, %xmm9; \ > > - vpcmpgtb UCHIGH_reg, reg2, %xmm10; \ > > - vpandn %xmm7, %xmm8, %xmm8; \ > > - vpandn %xmm9, %xmm10, %xmm10; \ > > - vpand LCQWORD_reg, %xmm8, %xmm8; \ > > - vpand LCQWORD_reg, %xmm10, %xmm10; \ > > - vpor reg1, %xmm8, reg1; \ > > - vpor reg2, %xmm10, reg2 > > + vpaddb LCASE_MIN_reg, reg1, %xmm7; \ > > + vpaddb LCASE_MIN_reg, reg2, %xmm8; \ > > + vpcmpgtb LCASE_MAX_reg, %xmm7, %xmm7; \ > > + vpcmpgtb LCASE_MAX_reg, %xmm8, %xmm8; \ > > + vpandn CASE_ADD_reg, %xmm7, %xmm7; \ > > + vpandn CASE_ADD_reg, %xmm8, %xmm8; \ > > + vpaddb %xmm7, reg1, reg1; \ > > + vpaddb %xmm8, reg2, reg2 > > # else > > # define TOLOWER(reg1, reg2) \ > > - movdqa reg1, %xmm7; \ > > - movdqa UCHIGH_reg, %xmm8; \ > > - movdqa reg2, %xmm9; \ > > - movdqa UCHIGH_reg, %xmm10; \ > > - pcmpgtb UCLOW_reg, %xmm7; \ > > - pcmpgtb reg1, %xmm8; \ > > - pcmpgtb UCLOW_reg, %xmm9; \ > > - pcmpgtb reg2, %xmm10; \ > > - pand %xmm8, %xmm7; \ > > - pand %xmm10, %xmm9; \ > > - pand LCQWORD_reg, %xmm7; \ > > - pand LCQWORD_reg, %xmm9; \ > > - por %xmm7, reg1; \ > > - por %xmm9, reg2 > > + movdqa LCASE_MIN_reg, %xmm7; \ > > + movdqa LCASE_MIN_reg, %xmm8; \ > > + paddb reg1, %xmm7; \ > > + paddb reg2, %xmm8; \ > > + pcmpgtb LCASE_MAX_reg, %xmm7; \ > > + pcmpgtb LCASE_MAX_reg, %xmm8; \ > > + pandn CASE_ADD_reg, %xmm7; \ > > + pandn CASE_ADD_reg, %xmm8; \ > > + paddb %xmm7, reg1; \ > > + paddb %xmm8, reg2 > > # endif > > TOLOWER (%xmm1, %xmm2) > > #else > > -- > > 2.25.1 > > > > LGTM. > > Reviewed-by: H.J. Lu > > Thanks. > > -- > H.J. I would like to backport this patch to release branches. Any comments or objections? --Sunil