From owner-freebsd-hackers@FreeBSD.ORG Fri Mar 18 16:15:29 2011 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 2E4071065670; Fri, 18 Mar 2011 16:15:29 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from mail.zoral.com.ua (mx0.zoral.com.ua [91.193.166.200]) by mx1.freebsd.org (Postfix) with ESMTP id 7A0248FC16; Fri, 18 Mar 2011 16:15:28 +0000 (UTC) Received: from deviant.kiev.zoral.com.ua (root@deviant.kiev.zoral.com.ua [10.1.1.148]) by mail.zoral.com.ua (8.14.2/8.14.2) with ESMTP id p2IGFOxb049492 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Fri, 18 Mar 2011 18:15:24 +0200 (EET) (envelope-from kostikbel@gmail.com) Received: from deviant.kiev.zoral.com.ua (kostik@localhost [127.0.0.1]) by deviant.kiev.zoral.com.ua (8.14.4/8.14.4) with ESMTP id p2IGFOuM078066; Fri, 18 Mar 2011 18:15:24 +0200 (EET) (envelope-from kostikbel@gmail.com) Received: (from kostik@localhost) by deviant.kiev.zoral.com.ua (8.14.4/8.14.4/Submit) id p2IGFOPI078065; Fri, 18 Mar 2011 18:15:24 +0200 (EET) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: deviant.kiev.zoral.com.ua: kostik set sender to kostikbel@gmail.com using -f Date: Fri, 18 Mar 2011 18:15:24 +0200 From: Kostik Belousov To: Andriy Gapon Message-ID: <20110318161524.GC78089@deviant.kiev.zoral.com.ua> References: <201103171436.22283.jkim@FreeBSD.org> <20110318162252.S984@besplex.bde.org> <20110318135647.GY78089@deviant.kiev.zoral.com.ua> <4D837F7F.2060403@freebsd.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="gL219CPYpMREpKpt" Content-Disposition: inline In-Reply-To: <4D837F7F.2060403@freebsd.org> User-Agent: Mutt/1.4.2.3i X-Virus-Scanned: clamav-milter 0.95.2 at skuns.kiev.zoral.com.ua X-Virus-Status: Clean X-Spam-Status: No, score=-3.4 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00, DNS_FROM_OPENWHOIS autolearn=no version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on skuns.kiev.zoral.com.ua Cc: freebsd-hackers@freebsd.org, Jung-uk Kim , Bruce Evans , Maxim Dounin Subject: Re: get_cyclecount(9) deprecation X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 18 Mar 2011 16:15:29 -0000 --gL219CPYpMREpKpt Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Mar 18, 2011 at 05:51:27PM +0200, Andriy Gapon wrote: > on 18/03/2011 15:56 Kostik Belousov said the following: > > On Fri, Mar 18, 2011 at 05:26:53PM +1100, Bruce Evans wrote: > > ... > >> - set cputicker() has some design bugs. It assumes that the tick freq= uency > >> is the same across all CPUs, but the TSC is per-CPU. I have an old = SMP > >> system with CPUs of different frequency that can demonstrate bugs fr= om > >> this. > > We definitely do not support configurations with different models of > > CPUs in SMP, this is what Simmetric is about. Different as in frequency > > or stepping. >=20 > Are there any fundamental reasons for us to not support that configuratio= n in > situations where hardware and BIOS (in x86 case) happen to support it? >=20 > I am personally more interested in non-uniform topologies like one packag= e having > two cores and another having four. We do not handle CPU errata/quirks individually per-core. I think that we assume that all cores have the same stepping and thus require the same workarounds, if any, as BSP. Also, I think tsc calibration is done only on BSP, but I may be wrong there. --gL219CPYpMREpKpt Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (FreeBSD) iEYEARECAAYFAk2DhRwACgkQC3+MBN1Mb4jtmACguqAsvWYeXb6Y23NHLqnblNiC UMEAoIu/L8aaw1tE+X5gnCw0Ir3euF7i =QS5W -----END PGP SIGNATURE----- --gL219CPYpMREpKpt--