Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752814AbdCHPJP (ORCPT ); Wed, 8 Mar 2017 10:09:15 -0500 Received: from mail-sn1nam01on0054.outbound.protection.outlook.com ([104.47.32.54]:54007 "EHLO NAM01-SN1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751578AbdCHPJM (ORCPT ); Wed, 8 Mar 2017 10:09:12 -0500 From: "Hadimani, Jagadish" To: Alexandre Belloni CC: "Shah, Nehal-bakulchandra" , "a.zummo@towertech.it" , "rtc-linux@googlegroups.com" , "linux-kernel@vger.kernel.org" Subject: Re: Kernel without RTC Thread-Topic: Kernel without RTC Thread-Index: AQHSlq51WoyjnX+SlEK+yretFlFLc6GK71AAgAAEfSY= Date: Wed, 8 Mar 2017 13:33:33 +0000 Message-ID: <016032B5-A966-48A9-B60D-AD75B8B857EE@amd.com> References: <221f9318-749f-03b8-aac8-85e9f9bec318@amd.com>,<20170308131730.zrznsnk5oldfuoib@piout.net> In-Reply-To: <20170308131730.zrznsnk5oldfuoib@piout.net> Accept-Language: en-US Content-Language: en-SG X-MS-Has-Attach: X-MS-TNEF-Correlator: authentication-results: free-electrons.com; dkim=none (message not signed) header.d=none;free-electrons.com; dmarc=none action=none header.from=amd.com; x-ms-exchange-messagesentrepresentingtype: 1 x-originating-ip: [122.171.49.155] x-microsoft-exchange-diagnostics: 1;MWHPR12MB1357;7:evH1KFr4O+4qC85VRN52rjDrQr4gnG07VUIReQni1Lhrf+NeT+66pQYDZazFbILe3Ni5TVkxXa60WIXoJJ71O6Ex+Q9RImRWu7gGR+BwrjgFzBea7WoevyW41aI+9z2Xaz5NX6+OPtG9hlGCE64ZRFnmJA82v24hPER840I2o+2mJ+9wA8RVgz37fKun/ktuM4WF7P0sgbvsoPIPQ8Wl5Wv+pSWUJoC0AvK6n/7/f8ykZ7Jwyy//hwugzSvqxEAJkEzgyCjZx57fHoIAyuZ3pkloj0uiUy9QkHF4kf0ooLtBt7LOCESB6DaM5Tby0rIKNUPiZQN5+147cII92spXdw==;20:mZLiiE7WaOwP4ByOtSgfpGEd79HCzZir4e6SUmPW/ltfF/HKOy2R0O2/NG8TsuEl0eFMbwY/MZeQQ1zNDa+sPxSK9MNX7b929VfYvnrUu8tyOZo0aT8aMRckH4SuLNO0nV7javbMjl2TYBQxZOv5QDFAW/xmrabnCafzu9z0uXcpXF6G3ZTAFygt+qFkzDLU0ZeRSrxibJ8PdzKRR5ew0peM7fZy5IqaXm3fv+73DAg4ZcFMrA8AblkOqf/IFboz x-forefront-antispam-report: SFV:SKI;SCL:-1SFV:NSPM;SFS:(10009020)(6009001)(39840400002)(39860400002)(39850400002)(39410400002)(39450400003)(209900001)(24454002)(377454003)(53376002)(3660700001)(82746002)(25786008)(110136004)(7736002)(83716003)(3480700004)(106116001)(3280700002)(305945005)(38730400002)(189998001)(8676002)(53546006)(4326008)(2950100002)(66066001)(6436002)(229853002)(5003630100001)(76176999)(50986999)(54356999)(6916009)(7116003)(33656002)(81166006)(99286003)(2906002)(9886003)(122556002)(86362001)(36756003)(8936002)(2900100001)(6306002)(53936002)(6512007)(6246003)(77096006)(102836003)(6116002)(3846002)(54906002)(6486002)(5660300001)(966004)(6506006)(104396002)(18886065003)(6606295002);DIR:OUT;SFP:1101;SCL:1;SRVR:MWHPR12MB1357;H:MWHPR12MB1533.namprd12.prod.outlook.com;FPR:;SPF:None;MLV:sfv;LANG:en; x-ms-office365-filtering-correlation-id: 2bd900f4-ef5b-4da4-8f30-08d46627b7bc x-ms-office365-filtering-ht: Tenant x-microsoft-antispam: UriScan:;BCL:0;PCL:0;RULEID:(22001)(48565401081);SRVR:MWHPR12MB1357; x-microsoft-antispam-prvs: x-exchange-antispam-report-test: UriScan:(58145275503218); x-exchange-antispam-report-cfa-test: BCL:0;PCL:0;RULEID:(6040375)(601004)(2401047)(8121501046)(5005006)(10201501046)(3002001)(6055026)(6041248)(20161123564025)(20161123558025)(20161123562025)(20161123560025)(20161123555025)(6072148);SRVR:MWHPR12MB1357;BCL:0;PCL:0;RULEID:;SRVR:MWHPR12MB1357; x-forefront-prvs: 02408926C4 spamdiagnosticoutput: 1:99 spamdiagnosticmetadata: NSPM Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-originalarrivaltime: 08 Mar 2017 13:33:33.7021 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-Transport-CrossTenantHeadersStamped: MWHPR12MB1357 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by mail.home.local id v28FAr3L024122 Content-Length: 984 Lines: 31 Hello Alexandre, I guess the Linux kernel uses HPET timer... But can we can force Linux kernel to use Tsc or per core timer... Sent from my iPhone > On 8 Mar 2017, at 6:47 PM, Alexandre Belloni wrote: > > Hi, > >> On 07/03/2017 at 00:48:18 +0530, Shah, Nehal-bakulchandra wrote: >> Hi, >> >> Currently we are having hardware which does not have RTC. It is single processor system. However it does have TSC timer. >> >> Now, how to use scheduler with only TSC as current kernel scheduler leverage the RTC for scheduling? I had seen one old patch >> >> http://marc.info/?l=linux-kernel&m=112013203625990&w=2 >> >> But i guess this patch was later on not taken, It will be great if you can some pointers to move forward? >> > > The kernel doesn't use the RTC for its time source so it can > already work without an RTC. > > > -- > Alexandre Belloni, Free Electrons > Embedded Linux and Kernel engineering > http://free-electrons.com