From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754030AbbDHMtT (ORCPT ); Wed, 8 Apr 2015 08:49:19 -0400 Received: from mail-ig0-f171.google.com ([209.85.213.171]:36532 "EHLO mail-ig0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752886AbbDHMtR (ORCPT ); Wed, 8 Apr 2015 08:49:17 -0400 Message-ID: <552523CA.8040106@gmail.com> Date: Wed, 08 Apr 2015 08:49:14 -0400 From: Austin S Hemmelgarn User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: Richard Weinberger , Pengfei Yuan <0xcoolypf@gmail.com> CC: Mike Galbraith , LKML Subject: Re: Why not build kernel with -O3 References: <1428388995.3152.10.camel@gmail.com> <1428401356.3152.38.camel@gmail.com> <55241C51.8040107@gmail.com> In-Reply-To: x-hashcash: 1:21:150408:richard.weinberger@gmail.com::e637938d4efb8260d29dcf678f701695:1cf86e348c1b909d x-hashcash: 1:21:150408:0xcoolypf@gmail.com::20fbae0fe21028296097aec39e04f577:48f53c463d1a2764 x-hashcash: 1:21:150408:umgwanakikbuti@gmail.com::8361e8926c065ae6c0696328c23d1ff7:4e5c835e256304f7 x-hashcash: 1:21:150408:linux-kernel@vger.kernel.org::bc70fe3ec79cc0f6b9d31d96ed0cf8a9:17a4e5d6276b0511 x-stampprotocols: hashcash:1:17;mbound:0:10:3000:5000 Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha1; boundary="------------ms020609060109020301060704" X-Antivirus: avast! (VPS 150408-1, 2015-04-08), Outbound message X-Antivirus-Status: Clean Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is a cryptographically signed message in MIME format. --------------ms020609060109020301060704 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable On 2015-04-08 08:19, Richard Weinberger wrote: > On Wed, Apr 8, 2015 at 3:00 AM, Pengfei Yuan <0xcoolypf@gmail.com> wrot= e: >> Could you please provide some examples that I can investigate? >> Thanks! > > It would be awesome if you could find out which gcc optimizations > cause the speed up. > "gcc -c -Q -O3 --help=3Doptimizers" will help you. > > Please also double check your results. > You need do to multiple runs, etc... > Especially the redis speed up looks odd. Does redis really spend that m= uch time > in the kernel? > My guess would be that much of the speed up is actually related to=20 context switch handling and the scheduling/statistics related code. --------------ms020609060109020301060704 Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="smime.p7s" Content-Description: S/MIME Cryptographic Signature MIAGCSqGSIb3DQEHAqCAMIACAQExCzAJBgUrDgMCGgUAMIAGCSqGSIb3DQEHAQAAoIIGuDCC BrQwggScoAMCAQICAxBuVTANBgkqhkiG9w0BAQ0FADB5MRAwDgYDVQQKEwdSb290IENBMR4w HAYDVQQLExVodHRwOi8vd3d3LmNhY2VydC5vcmcxIjAgBgNVBAMTGUNBIENlcnQgU2lnbmlu ZyBBdXRob3JpdHkxITAfBgkqhkiG9w0BCQEWEnN1cHBvcnRAY2FjZXJ0Lm9yZzAeFw0xNTAz MjUxOTM0MzhaFw0xNTA5MjExOTM0MzhaMGMxGDAWBgNVBAMTD0NBY2VydCBXb1QgVXNlcjEj MCEGCSqGSIb3DQEJARYUYWhmZXJyb2luN0BnbWFpbC5jb20xIjAgBgkqhkiG9w0BCQEWE2Fo ZW1tZWxnQG9oaW9ndC5jb20wggIiMA0GCSqGSIb3DQEBAQUAA4ICDwAwggIKAoICAQCdD/zW 2rRAFCLnDfXpWxU1+ODqRVUgzHvrRO7ADUxRo1CBDc3JSX5TIW2OGmQ3DAKGOACp8Z0sgxMc B05tzAZ/M7m4jajVrwwdVCdrwVGxTdAai7Kwg4ZCVfyMVhcwo8R2eW3QahBx34G0RKumK9sZ ZQSQ+zULAzpY6uz7T1sAk/erMoivRXF6u8WvOsLkOD1F/Xyv1ZccSUG5YeDgZgc0nZUBvyIp zXSHjgWerFkrxEM3y2z/Ff3eL1sgGYecV/I1F+I5S01V7Kclt/qRW10c/4JEGRcI1FmrJBPu BtMYPbg/3Y9LZROYN+mVIFxZxOfrmjfFZ96xt/TaMXo8vcEKtWcNEjhGBjEbfMUEm4aq8ygQ 4MuEcpJc8DJCHBkg2KBk13DkbU2qNepTD6Uip1C+g+KMr0nd6KOJqSH27ZuNY4xqV4hIxFHp ex0zY7mq6fV2o6sKBGQzRdI20FDYmNjsLJwjH6qJ8laxFphZnPRpBThmu0AjuBWE72GnI1oA aO+bs92MQGJernt7hByCnDO82W/ykbVz+Ge3Sax8NY0m2Xdvp6WFDY/PjD9CdaJ9nwQGsUSa N54lrZ2qMTeCI9Vauwf6U69BA42xgk65VvxvTNqji+tZ4aZbarZ7el2/QDHOb/rRwlCFplS/ z4l1f1nOrE6bnDl5RBJyW3zi74P6GwIDAQABo4IBWTCCAVUwDAYDVR0TAQH/BAIwADBWBglg hkgBhvhCAQ0ESRZHVG8gZ2V0IHlvdXIgb3duIGNlcnRpZmljYXRlIGZvciBGUkVFIGhlYWQg b3ZlciB0byBodHRwOi8vd3d3LkNBY2VydC5vcmcwDgYDVR0PAQH/BAQDAgOoMEAGA1UdJQQ5 MDcGCCsGAQUFBwMEBggrBgEFBQcDAgYKKwYBBAGCNwoDBAYKKwYBBAGCNwoDAwYJYIZIAYb4 QgQBMDIGCCsGAQUFBwEBBCYwJDAiBggrBgEFBQcwAYYWaHR0cDovL29jc3AuY2FjZXJ0Lm9y ZzAxBgNVHR8EKjAoMCagJKAihiBodHRwOi8vY3JsLmNhY2VydC5vcmcvcmV2b2tlLmNybDA0 BgNVHREELTArgRRhaGZlcnJvaW43QGdtYWlsLmNvbYETYWhlbW1lbGdAb2hpb2d0LmNvbTAN BgkqhkiG9w0BAQ0FAAOCAgEAGvl7xb42JMRH5D/vCIDYvFY3dR2FPd5kmOqpKU/fvQ8ovmJa p5N/FDrsCL+YdslxPY+AAn78PYmL5pFHTdRadT++07DPIMtQyy2qd+XRmz6zP8Il7vGcEDmO WmMLYMq4xV9s/N7t7JJp6ftdIYUcoTVChUgilDaRWMLidtslCdRsBVfUjPb1bF5Ua31diKDP e0M9/e2CU36rbcTtiNCXhptMigzuL3zJXUf2B9jyUV8pnqNEQH36fqJ7YTBLcpq3aYa2XbAH Hgx9GehJBIqwspDmhPCFZ/QmqUXCkt+XfvinQ2NzKR6P3+OdYbwqzVX8BdMeojh7Ig8x/nIx mQ+/ufstL1ZYp0bg13fyK/hPYSIBpayaC76vzWovkIm70DIDRIFLi20p/qTd7rfDYy831Hjm +lDdCECF9bIXEWFk33kA97dgQIMbf5chEmlFg8S0e4iw7LMjvRqMX3eCD8GJ2+oqyZUwzZxy S0Mx+rBld5rrN7LsXwZ671HsGqNeYbYeU25e7t7/Gcc6Bd/kPfA+adEuUGFcvUKH3trDYqNq 6mOkAd8WO/mQadlc3ztS++XDMhmIpfBre9MPAr6usqf+wc+R8Nk9KLK39kEgrqVfzc/fgf8L MaD4rHnusdg4gca6Yi+kNrm99anw7SwaBrBvULYBp7ixNRUhaYiNW4YjTrYxggShMIIEnQIB ATCBgDB5MRAwDgYDVQQKEwdSb290IENBMR4wHAYDVQQLExVodHRwOi8vd3d3LmNhY2VydC5v cmcxIjAgBgNVBAMTGUNBIENlcnQgU2lnbmluZyBBdXRob3JpdHkxITAfBgkqhkiG9w0BCQEW EnN1cHBvcnRAY2FjZXJ0Lm9yZwIDEG5VMAkGBSsOAwIaBQCgggH1MBgGCSqGSIb3DQEJAzEL BgkqhkiG9w0BBwEwHAYJKoZIhvcNAQkFMQ8XDTE1MDQwODEyNDkxNFowIwYJKoZIhvcNAQkE MRYEFI+tu6YoFMyZnaRB/uZ2UAxGczDJMGwGCSqGSIb3DQEJDzFfMF0wCwYJYIZIAWUDBAEq MAsGCWCGSAFlAwQBAjAKBggqhkiG9w0DBzAOBggqhkiG9w0DAgICAIAwDQYIKoZIhvcNAwIC AUAwBwYFKw4DAgcwDQYIKoZIhvcNAwICASgwgZEGCSsGAQQBgjcQBDGBgzCBgDB5MRAwDgYD VQQKEwdSb290IENBMR4wHAYDVQQLExVodHRwOi8vd3d3LmNhY2VydC5vcmcxIjAgBgNVBAMT GUNBIENlcnQgU2lnbmluZyBBdXRob3JpdHkxITAfBgkqhkiG9w0BCQEWEnN1cHBvcnRAY2Fj ZXJ0Lm9yZwIDEG5VMIGTBgsqhkiG9w0BCRACCzGBg6CBgDB5MRAwDgYDVQQKEwdSb290IENB MR4wHAYDVQQLExVodHRwOi8vd3d3LmNhY2VydC5vcmcxIjAgBgNVBAMTGUNBIENlcnQgU2ln bmluZyBBdXRob3JpdHkxITAfBgkqhkiG9w0BCQEWEnN1cHBvcnRAY2FjZXJ0Lm9yZwIDEG5V MA0GCSqGSIb3DQEBAQUABIICACkYe468tykaegFXl2gj7AJuICzRFgTAbc5lA4mhmSI9JUy7 ftKBKx83WlE5XzrXXR0HsiLlWFHwqroGuc3CwIZmef6fUTJWfh15VH8UwuE/3WgxKIPXGMNb 8QWzpCc+Soi3xITY/D8r2DU0Glfuqs9OYBrqXVCpr0i5w9oRgeAvdf0wc1UlVXl0VLTaJ0r9 oJ0KGIOnBX2sip8qPeoEeg4h0FdLJQ13ldUgutI2XpXr/Kv4y9pTTrdQ/blkhvDlRbHVgSs9 gF0Cacdz50BpLja+sV3sH9s50IuBOeQNK9mPoNS9sMAh5oK3H2pK5H3yycmTIT4QSLQWlgLG 68cxSJpKVfZyoFhpCzt+Dn19RaCwFC0qs65RZ11pow2Ohpcmduj3SYsLUe5n70kMlCjlLd5y /Cmc9/6SQc6qlfchx0iMUgKURLhs+xLCar8GEJj6yGRadDOPz6MGYmfUxDwKTw2eWVEXHcQG HPfBqyGUIQAxK3DgC/NKsW3Z5hX7gytlXFpzERV+Rk+n2pLvi8bf7TLSWHOzwnl+2cZZTXA8 UHoHehSvy2FIIXvEan/2v3SBUtmKJiflJYMO7fgxmkb6ON/ZhlDgT2gl/WAS20sL0l/+ulYP +GwGcLC8kcoPcNpQo17mEiZxWnPRch+vs8vLTZ4ROr0nWhYx/GsAZfqF+6d3AAAAAAAA --------------ms020609060109020301060704--