Date: Thu, 22 Jan 2015 08:15:00 +1100 From: Peter Jeremy <peter@rulingia.com> To: Bryan Venteicher <bryanv@daemoninthecloset.org> Cc: FreeBSD-current <freebsd-current@freebsd.org>, freebsd-arch@freebsd.org Subject: Re: [CFT] Paravirtualized KVM clock Message-ID: <20150121211500.GA32478@server.rulingia.com> In-Reply-To: <CAMo0n6QUp3iZ2fEqbrsD2MhEsWWOPTLisd9iB7TNEvbevcK0Fw@mail.gmail.com> References: <CAMo0n6QUp3iZ2fEqbrsD2MhEsWWOPTLisd9iB7TNEvbevcK0Fw@mail.gmail.com>
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--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 <bryanv@daemoninthecloset.o= rg> 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--
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