From owner-freebsd-current@FreeBSD.ORG Wed Jan 21 21:58:07 2015 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 1BF29E5C; Wed, 21 Jan 2015 21:58:07 +0000 (UTC) Received: from vps.rulingia.com (vps.rulingia.com [103.243.244.15]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "vps.rulingia.com", Issuer "CAcert Class 3 Root" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 488F03ED; Wed, 21 Jan 2015 21:58:05 +0000 (UTC) Received: from server.rulingia.com (c220-239-242-83.belrs5.nsw.optusnet.com.au [220.239.242.83]) by vps.rulingia.com (8.14.9/8.14.9) with ESMTP id t0LLF8JR030205 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 22 Jan 2015 08:15:13 +1100 (AEDT) (envelope-from peter@rulingia.com) X-Bogosity: Ham, spamicity=0.000000 Received: from server.rulingia.com (localhost.rulingia.com [127.0.0.1]) by server.rulingia.com (8.14.9/8.14.9) with ESMTP id t0LLF21G032529 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Thu, 22 Jan 2015 08:15:02 +1100 (AEDT) (envelope-from peter@server.rulingia.com) Received: (from peter@localhost) by server.rulingia.com (8.14.9/8.14.9/Submit) id t0LLF0bn032528; Thu, 22 Jan 2015 08:15:00 +1100 (AEDT) (envelope-from peter) Date: Thu, 22 Jan 2015 08:15:00 +1100 From: Peter Jeremy To: Bryan Venteicher Subject: Re: [CFT] Paravirtualized KVM clock Message-ID: <20150121211500.GA32478@server.rulingia.com> References: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="x+6KMIRAuhnl3hBn" Content-Disposition: inline In-Reply-To: X-PGP-Key: http://www.rulingia.com/keys/peter.pgp User-Agent: Mutt/1.5.23 (2014-03-12) Cc: FreeBSD-current , freebsd-arch@freebsd.org X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 21 Jan 2015 21:58:07 -0000 --x+6KMIRAuhnl3hBn Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2015-Jan-04 11:56:14 -0600, Bryan Venteicher wrote: >For the last few weeks, I've been working on adding support for KVM clock >in the projects/paravirt branch. Currently, a KVM VM guest will end up >selecting either the HPET or ACPI as the timecounter source. Unfortunately, >this is very costly since every timecounter fetch causes a VM exit. KVM >clock allows the guest to use the TSC instead; it is very similar to the >existing Xen timer. A somewhat late response but have you looked at https://github.com/blitz/freebsd/commit/cdc5f872b3e48cc0dda031fc7d6bdedc65c= 3148f I've been running this[*] on a Google Compute Engine instance for about 6 months without problems. [*] I had to patch out the test for KVM_FEATURE_CLOCKSOURCE_STABLE_BIT but I think that's a GCE issue. --=20 Peter Jeremy --x+6KMIRAuhnl3hBn Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQJ8BAEBCgBmBQJUwBbUXxSAAAAAAC4AKGlzc3Vlci1mcHJAbm90YXRpb25zLm9w ZW5wZ3AuZmlmdGhob3JzZW1hbi5uZXRFRUIyOTg2QzMwNjcxRTc0RTY1QzIyN0Ux NkE1OTdBMEU0QTIwQjM0AAoJEBall6Dkogs0EPcP/1rx8DK61b3Bz7Oiju0gbkXd OJrhFO/WVuJ6P7yRW3Feg17C2+FVMqnqPZ5XyaaQNBGnUuHuEYx4o5JM7OlrfeLW WVog+gr0Gg7th/lMPkFFy+WK7QlX/nDFLbRnkcOdiuqGIJZ4EDqYTwkmJxCWqNOv ynlq8BrKUMV2Ff2NeUFx8EnoqxYiuP48ExpLTlJcbHylRKFWkBPUOjKX97ljsO9o X1WPzGH3XmHzEVkEANlwTDqV/hYVwKxcLuyTVsmxn5K0L/XV/jn/qI7ukWfWk0VO WDFXkZUZ4WkrrP5O/5C/7j7GjvPOk0JYK9YnI7wzrh9x5BI86L5PH//1CqL/splo 9MeiS95Pm8LVqK0ggjNt+kYhail1DdCrufH8OdPcE9/rQVCEXKTsxPygz3sdW5AE ttQlikoh2rXFfyPbJlYxTTpoJx6lHhx/eBlhTVgMoX32bAYlR4h7laXJ1q2/Mb1w FtzjKRjHGso2iiFiP+NsomHWNhJRGKTT/gcQnJ33xCa6B6Asew+UpeCAVM4brGxg NWeAkL6nt3JsOBgEKiuNksp7HZituMYRpEai2fkKCcqPcHplutD8qSd93ALO8anY M0Iggid9bE/zfMDQltm6A/SdYFb0HrXEFCDzQffLbU3nwOGi+CSM2BnoV/1uZggn 9v+JtxMBJBKhL+W20HK2 =PgOy -----END PGP SIGNATURE----- --x+6KMIRAuhnl3hBn--