On Mon, 2015-09-28 at 15:13 +0800, Haozhong Zhang wrote: > This patch adds an option 'vtsc_khz' to allow users to set vcpu's TSC > rate in KHz. In the case that tsc_mode = 'default', the default value of > 'vtsc_khz' option is the host TSC rate which is used when 'vtsc_khz' > option is set to 0 or does not appear in the configuration. In all other > cases of tsc_mode, 'vtsc_khz' option is just ignored. > > Another purpose of adding this option is to keep vcpu's TSC rate across > guest reboot. In existing code, a new domain is created from the > configuration of the previous domain which was just rebooted. vcpu's TSC > rate is not stored in the configuration and the host TSC rate is the > used as vcpu's TSC rate. This works fine unless the previous domain was > migrated from another host machine with a different host TSC rate than > the current one.
I understand why this is necessary over a migration, but why is it important to be able to retain the TSC rate across a reboot? What is the usecase there? > Signed-off-by: Haozhong Zhang <haozhong.zh...@intel.com> > --- > tools/libxl/libxl_types.idl | 1 + > tools/libxl/libxl_x86.c | 4 +++- > tools/libxl/xl_cmdimpl.c | 22 ++++++++++++++++++++++ The documentation should be patched at the same time. At least the xl.cfg manpage, but I think there is also a specific document about time and the TSC which should also be updated. Ian. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
