Date: Fri, 10 Apr 2015 18:26:42 -0500 From: Bryan Venteicher <bryanv@daemoninthecloset.org> To: Ryan Stone <rysto32@gmail.com> Cc: "freebsd-virtualization@freebsd.org" <freebsd-virtualization@freebsd.org>, Allan Jude <allanjude@freebsd.org> Subject: Re: bhyve clock problem, solved by kern.timecounter.hardware="TSC-low" in /etc/sysctl.conf Message-ID: <CAMo0n6T0dCpkg4qUsJNh=t6g0o1S5k9CpJRLPn7sWXvCj4MHSg@mail.gmail.com> In-Reply-To: <CAFMmRNyp_m4m7H1u5N4O1B35Rt3H_HcL-rUDRMMyY6a6FOtB%2Bw@mail.gmail.com> References: <552809F4.6070206@redbarn.org> <CAOb7DXGAWiTUvmq5xJT8Z8W9D3hFuWeHQ-vbADw2AP0Fv4e8Lw@mail.gmail.com> <552810CE.7020502@redbarn.org> <5528115B.7060509@freebsd.org> <CAFMmRNyp_m4m7H1u5N4O1B35Rt3H_HcL-rUDRMMyY6a6FOtB%2Bw@mail.gmail.com>
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On Fri, Apr 10, 2015 at 4:36 PM, Ryan Stone <rysto32@gmail.com> wrote: > Using the TSC as the default timecounter in a VM is dangerous. On some > hardware, the TSC is not synchronized across all CPU cores. This means > that if a VM migrates from one core to another, it could see the > timecounter value go backwards. Time jumping backwards can cause all kin= ds > of hilarity. > > What's really needed is for bhyve to support KVM clock or a similar schem= e > (brianv@ might also still need to commit the guest side of KVM clock as > well). > =E2=80=8BI still need to after addressing some review comments first, but I= 've been perpetually busy with my job. I hope to get to it RealSoon.=E2=80=8B _______________________________________________ > freebsd-virtualization@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-virtualization > To unsubscribe, send any mail to " > freebsd-virtualization-unsubscribe@freebsd.org" >
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