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GET /api/patches/817321/?format=api
{ "id": 817321, "url": "http://patchwork.ozlabs.org/api/patches/817321/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linuxppc-dev/patch/1505950480-14830-2-git-send-email-wei.guo.simon@gmail.com/", "project": { "id": 2, "url": "http://patchwork.ozlabs.org/api/projects/2/?format=api", "name": "Linux PPC development", "link_name": "linuxppc-dev", "list_id": "linuxppc-dev.lists.ozlabs.org", "list_email": "linuxppc-dev@lists.ozlabs.org", "web_url": "https://github.com/linuxppc/wiki/wiki", "scm_url": "https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git", "webscm_url": "https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/", "list_archive_url": "https://lore.kernel.org/linuxppc-dev/", "list_archive_url_format": "https://lore.kernel.org/linuxppc-dev/{}/", "commit_url_format": "https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?id={}" }, "msgid": "<1505950480-14830-2-git-send-email-wei.guo.simon@gmail.com>", "list_archive_url": "https://lore.kernel.org/linuxppc-dev/1505950480-14830-2-git-send-email-wei.guo.simon@gmail.com/", "date": "2017-09-20T23:34:38", "name": "[v2,1/3] powerpc/64: Align bytes before fall back to .Lshort in powerpc64 memcmp().", "commit_ref": null, "pull_url": null, "state": "superseded", "archived": true, "hash": "a33f94cfaeffa5127153514689592bed324609c4", "submitter": { "id": 68632, "url": "http://patchwork.ozlabs.org/api/people/68632/?format=api", "name": "Simon Guo", "email": "wei.guo.simon@gmail.com" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/linuxppc-dev/patch/1505950480-14830-2-git-send-email-wei.guo.simon@gmail.com/mbox/", "series": [ { "id": 4540, "url": "http://patchwork.ozlabs.org/api/series/4540/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=4540", "date": "2017-09-20T23:34:38", "name": "powerpc/64: memcmp() optimization", "version": 2, "mbox": "http://patchwork.ozlabs.org/series/4540/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/817321/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/817321/checks/", "tags": {}, "related": [], "headers": { "Return-Path": "<linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org>", "X-Original-To": [ "patchwork-incoming@ozlabs.org", "linuxppc-dev@lists.ozlabs.org" ], "Delivered-To": [ "patchwork-incoming@ozlabs.org", "linuxppc-dev@lists.ozlabs.org" ], "Received": [ "from lists.ozlabs.org (lists.ozlabs.org [103.22.144.68])\n\t(using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby ozlabs.org (Postfix) with ESMTPS id 3xz2Qv3xnlz9sRV\n\tfor <patchwork-incoming@ozlabs.org>;\n\tFri, 22 Sep 2017 15:41:27 +1000 (AEST)", "from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3])\n\tby lists.ozlabs.org (Postfix) with ESMTP id 3xz2Qv2k9GzDsN1\n\tfor <patchwork-incoming@ozlabs.org>;\n\tFri, 22 Sep 2017 15:41:27 +1000 (AEST)", "from mail-pf0-x241.google.com (mail-pf0-x241.google.com\n\t[IPv6:2607:f8b0:400e:c00::241])\n\t(using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128\n\tbits)) (No client certificate requested)\n\tby lists.ozlabs.org (Postfix) with ESMTPS id 3xz2Mt4DSjzDrJL\n\tfor <linuxppc-dev@lists.ozlabs.org>;\n\tFri, 22 Sep 2017 15:38:50 +1000 (AEST)", "by mail-pf0-x241.google.com with SMTP id h4so65827pfk.0\n\tfor <linuxppc-dev@lists.ozlabs.org>;\n\tThu, 21 Sep 2017 22:38:50 -0700 (PDT)", "from simonLocalRHEL7.x64 ([112.73.6.48])\n\tby smtp.gmail.com with ESMTPSA id\n\tr12sm6234639pfd.187.2017.09.21.22.38.45\n\t(version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128);\n\tThu, 21 Sep 2017 22:38:48 -0700 (PDT)" ], "Authentication-Results": [ "ozlabs.org;\n\tdkim=fail reason=\"signature verification failed\" (2048-bit key;\n\tunprotected) header.d=gmail.com header.i=@gmail.com\n\theader.b=\"l/m+3R5a\"; 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a=rsa-sha256; c=relaxed/relaxed;\n\td=1e100.net; s=20161025;\n\th=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to\n\t:references:mime-version:content-transfer-encoding;\n\tbh=6lXgsb55BH7QEtG975rnFegiAD6Xma1bNAxwWEsa07k=;\n\tb=e9p/o8fGphiRHdCtsjgCJqO34nAL11nZq9WnjQ4C8OMhNI2J89WhjVQ4kCsxIK52Du\n\tTh3VEzwkkfVYKvJQlEuonLgurSRxEEk69unJZtLtUEMLqd1GEBoEYAsjnrb7jtrhkM1s\n\tLCXAaLSeRFu0A8Vfu6cVmiymRVoVmOlvexLlQD5o1M3Rxa87fn0lJYn30cHBGt0lsdc/\n\tf12zGAInu3ZvoZ/+xsFaj9cMDR5Anj+KNindrRiK6QJxjED2nlyJQhuHlYtcXp6c7pMI\n\t/fT1r3NV00OmCChCunYCAqg2XriZzyOria4I9D6x8NB6kAo/dNASvI9taDbwbrNkRxW3\n\tNnYg==", "X-Gm-Message-State": "AHPjjUjXVWan1ilK3zUb2/xQ92tm4FGsbuTbIbQ6pVKKJ+46wrl4+oae\n\t6yX9c0oTy23vAnlvKir8tFMBKQ==", "X-Google-Smtp-Source": "AOwi7QASsPdahGb0HCrkp5bOhjQcWD1rEesmxVyNp/qPElQoMQp1ynBGGSkBntz46L4ukH/NfvkjKw==", "X-Received": "by 10.101.76.141 with SMTP id m13mr2156798pgt.103.1506058728616; \n\tThu, 21 Sep 2017 22:38:48 -0700 (PDT)", "From": "wei.guo.simon@gmail.com", "To": "linuxppc-dev@lists.ozlabs.org", "Subject": "[PATCH v2 1/3] powerpc/64: Align bytes before fall back to .Lshort\n\tin powerpc64 memcmp().", "Date": "Thu, 21 Sep 2017 07:34:38 +0800", "Message-Id": "<1505950480-14830-2-git-send-email-wei.guo.simon@gmail.com>", "X-Mailer": "git-send-email 1.8.3.1", "In-Reply-To": "<1505950480-14830-1-git-send-email-wei.guo.simon@gmail.com>", "References": "<1505950480-14830-1-git-send-email-wei.guo.simon@gmail.com>", "MIME-Version": "1.0", "Content-Type": "text/plain; charset=UTF-8", "Content-Transfer-Encoding": "8bit", "X-BeenThere": "linuxppc-dev@lists.ozlabs.org", "X-Mailman-Version": "2.1.24", "Precedence": "list", "List-Id": "Linux on PowerPC Developers Mail List\n\t<linuxppc-dev.lists.ozlabs.org>", "List-Unsubscribe": "<https://lists.ozlabs.org/options/linuxppc-dev>,\n\t<mailto:linuxppc-dev-request@lists.ozlabs.org?subject=unsubscribe>", "List-Archive": "<http://lists.ozlabs.org/pipermail/linuxppc-dev/>", "List-Post": "<mailto:linuxppc-dev@lists.ozlabs.org>", "List-Help": "<mailto:linuxppc-dev-request@lists.ozlabs.org?subject=help>", "List-Subscribe": "<https://lists.ozlabs.org/listinfo/linuxppc-dev>,\n\t<mailto:linuxppc-dev-request@lists.ozlabs.org?subject=subscribe>", "Cc": "Simon Guo <wei.guo.simon@gmail.com>,\n\tDavid Laight <David.Laight@ACULAB.COM>, \n\t\"Naveen N. Rao\" <naveen.n.rao@linux.vnet.ibm.com>", "Errors-To": "linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org", "Sender": "\"Linuxppc-dev\"\n\t<linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org>" }, "content": "From: Simon Guo <wei.guo.simon@gmail.com>\n\nCurrently memcmp() 64bytes version in powerpc will fall back to .Lshort\n(compare per byte mode) if either src or dst address is not 8 bytes\naligned. It can be opmitized if both addresses are with the same offset\nwith 8 bytes boundary.\n\nmemcmp() can compare the unaligned bytes within 8 bytes boundary firstly\nand then compare the rest 8-bytes-aligned content with .Llong mode.\n\nThis patch optmizes memcmp() behavior in this situation.\n\nTest result:\n\n(1) 256 bytes\nTest with the existing tools/testing/selftests/powerpc/stringloops/memcmp:\n- without patch\n 50.996607479 seconds time elapsed ( +- 0.01% )\n- with patch\n 28.033316997 seconds time elapsed ( +- 0.01% )\n\t\t-> There is ~+81% percent improvement\n\n(2) 32 bytes\nTo observe performance impact on < 32 bytes, modify\ntools/testing/selftests/powerpc/stringloops/memcmp.c with following:\n-------\n #include <string.h>\n #include \"utils.h\"\n\n-#define SIZE 256\n+#define SIZE 32\n #define ITERATIONS 10000\n\n int test_memcmp(const void *s1, const void *s2, size_t n);\n--------\n\n- Without patch\n 0.392578831 seconds time elapsed ( +- 0.05% )\n- with patch\n 0.358446662 seconds time elapsed ( +- 0.04% )\n\t\t-> There is ～+9% improvement\n\n(3) 0~8 bytes\nTo observe <8 bytes performance impact, modify\ntools/testing/selftests/powerpc/stringloops/memcmp.c with following:\n-------\n #include <string.h>\n #include \"utils.h\"\n\n-#define SIZE 256\n-#define ITERATIONS 10000\n+#define SIZE 8\n+#define ITERATIONS 1000000\n\n int test_memcmp(const void *s1, const void *s2, size_t n);\n-------\n- Without patch\n 3.168752060 seconds time elapsed ( +- 0.10% )\n- With patch\n 3.153030138 seconds time elapsed ( +- 0.09% )\n\t\t-> They are nearly the same. (-0.4%)\n\nSigned-off-by: Simon Guo <wei.guo.simon@gmail.com>\n---\n arch/powerpc/lib/memcmp_64.S | 99 +++++++++++++++++++++++++++++++++++++++++---\n 1 file changed, 93 insertions(+), 6 deletions(-)", "diff": "diff --git a/arch/powerpc/lib/memcmp_64.S b/arch/powerpc/lib/memcmp_64.S\nindex d75d18b..6dccfb8 100644\n--- a/arch/powerpc/lib/memcmp_64.S\n+++ b/arch/powerpc/lib/memcmp_64.S\n@@ -24,28 +24,35 @@\n #define rH\tr31\n \n #ifdef __LITTLE_ENDIAN__\n+#define LH\tlhbrx\n+#define LW\tlwbrx\n #define LD\tldbrx\n #else\n+#define LH\tlhzx\n+#define LW\tlwzx\n #define LD\tldx\n #endif\n \n _GLOBAL(memcmp)\n \tcmpdi\tcr1,r5,0\n \n-\t/* Use the short loop if both strings are not 8B aligned */\n-\tor\tr6,r3,r4\n+\t/* Use the short loop if the src/dst addresses are not\n+\t * with the same offset of 8 bytes align boundary.\n+\t */\n+\txor\tr6,r3,r4\n \tandi.\tr6,r6,7\n \n-\t/* Use the short loop if length is less than 32B */\n-\tcmpdi\tcr6,r5,31\n+\t/* fall back to short loop if compare at aligned addrs\n+\t * with less than 8 bytes.\n+\t */\n+\tcmpdi cr6,r5,7\n \n \tbeq\tcr1,.Lzero\n \tbne\t.Lshort\n-\tbgt\tcr6,.Llong\n+\tbgt\tcr6,.L8bytes_make_align_start\n \n .Lshort:\n \tmtctr\tr5\n-\n 1:\tlbz\trA,0(r3)\n \tlbz\trB,0(r4)\n \tsubf.\trC,rB,rA\n@@ -78,6 +85,78 @@ _GLOBAL(memcmp)\n \tli\tr3,0\n \tblr\n \n+.L8bytes_make_align_start:\n+\t/* attempt to compare bytes not aligned with 8 bytes so that\n+\t * left comparison can run based on 8 bytes alignment.\n+\t */\n+\tandi. r6,r3,7\n+\tbeq .L8bytes_aligned\n+\n+\t/* Try to compare the first double word which is not 8 bytes aligned:\n+\t * load the first double word at (src & ~7UL) and shift left appropriate\n+\t * bits before comparision.\n+\t */\n+\tclrlwi r6,r3,29\n+\trlwinm r6,r6,3,0,28\n+\tclrrdi\tr3,r3,3\n+\tclrrdi\tr4,r4,3\n+\tLD\trA,0,r3\n+\tLD\trB,0,r4\n+\tsld\trA,rA,r6\n+\tsld\trB,rB,r6\n+\tcmpld\tcr0,rA,rB\n+\tbne\tcr0,.LcmpAB_lightweight\n+\tsrwi\tr6,r6,3\n+\tsubfic r6,r6,8\n+\tsubfc.\tr5,r6,r5\n+\tbeq\t.Lzero\n+\taddi\tr3,r3,8\n+\taddi\tr4,r4,8\n+\n+.L8bytes_aligned:\n+\t/* now we are aligned with 8 bytes.\n+\t * Use .Llong loop if left cmp bytes are equal or greater than 32B.\n+\t */\n+\tcmpdi cr6,r5,31\n+\tbgt\tcr6,.Llong\n+\n+\tcmpdi cr6,r5,7\n+\tbgt\tcr6,.Lcmp_8bytes_31bytes\n+\n+.Lcmp_rest_lt8bytes:\n+\t/* Here we have only less than 8 bytes to compare with. Addresses\n+\t * are aligned with 8 bytes.\n+\t * The next double words are load and shift right with appropriate\n+\t * bits.\n+\t */\n+\tsubfic r6,r5,8\n+\trlwinm r6,r6,3,0,28\n+\tLD\trA,0,r3\n+\tLD\trB,0,r4\n+\tsrd\trA,rA,r6\n+\tsrd\trB,rB,r6\n+\tcmpld\tcr0,rA,rB\n+\tbne\tcr0,.LcmpAB_lightweight\n+\tbeq\t.Lzero\n+\n+.Lcmp_8bytes_31bytes:\n+\t/* compare 8 ~ 31 bytes with 8 bytes aligned */\n+\tsrdi. r0,r5,3\n+\tclrldi r5,r5,61\n+\tmtctr r0\n+831:\n+\tLD\trA,0,r3\n+\tLD\trB,0,r4\n+\tcmpld\tcr0,rA,rB\n+\tbne\tcr0,.LcmpAB_lightweight\n+\taddi\tr3,r3,8\n+\taddi\tr4,r4,8\n+\tbdnz\t831b\n+\n+\tcmpwi r5,0\n+\tbeq\t.Lzero\n+\tb\t.Lcmp_rest_lt8bytes\n+\n .Lnon_zero:\n \tmr\tr3,rC\n \tblr\n@@ -232,4 +311,12 @@ _GLOBAL(memcmp)\n \tld\tr28,-32(r1)\n \tld\tr27,-40(r1)\n \tblr\n+\n+.LcmpAB_lightweight: /* skip NV GPRS restore */\n+\tli\tr3,1\n+\tbgt\tcr0,8f\n+\tli\tr3,-1\n+8:\n+\tblr\n+\n EXPORT_SYMBOL(memcmp)\n", "prefixes": [ "v2", "1/3" ] }