Re: [Xen-devel] [PATCH v3] new config option vtsc_tolerance_khz to avoid TSC emulation

So, how do we address the performance regression fixed by this patch? Olaf Am Mon, 12 Mar 2018 10:15:08 +0100 schrieb Olaf Hering : > Am Tue, 6 Mar 2018 11:07:54 + > schrieb Andrew Cooper : > > > > Add a new domctl

Re: [Xen-devel] [PATCH v3] new config option vtsc_tolerance_khz to avoid TSC emulation

Am Tue, 6 Mar 2018 11:07:54 + schrieb Andrew Cooper : > > Add a new domctl XEN_DOMCTL_set_vtsc_tolerance_khz to adjust the > > tolerance value of a running domU that is supposed to be migrated. > Please can we not proliferate the domctls. > This looks like it

Re: [Xen-devel] [PATCH v3] new config option vtsc_tolerance_khz to avoid TSC emulation

>>> On 06.03.18 at 12:07, wrote: > On 06/03/18 10:41, Olaf Hering wrote: >> With this option the host admin can decide how a domU should behave when >> it is migrated across systems of the same class. Since there is always >> some jitter when Xen calibrates the cpu_khz

Re: [Xen-devel] [PATCH v3] new config option vtsc_tolerance_khz to avoid TSC emulation

Am Tue, 6 Mar 2018 11:07:54 + schrieb Andrew Cooper : > > One option to avoid the TSC option is to run domUs with tsc_mode=native. > > This has the drawback that migrating a domU from a "2.3GHz" class host > > to a "2.4GHz" class host may change the rate at wich the

Re: [Xen-devel] [PATCH v3] new config option vtsc_tolerance_khz to avoid TSC emulation

On 06/03/18 10:41, Olaf Hering wrote: > Add an option to control when vTSC emulation will be activated for a > domU with tsc_mode=default. Without such option each TSC access from > domU will be emulated, which causes a significant perfomance drop for > workloads that make use of rdtsc. > > Add a

[Xen-devel] [PATCH v3] new config option vtsc_tolerance_khz to avoid TSC emulation

Add an option to control when vTSC emulation will be activated for a domU with tsc_mode=default. Without such option each TSC access from domU will be emulated, which causes a significant perfomance drop for workloads that make use of rdtsc. Add a new domctl XEN_DOMCTL_set_vtsc_tolerance_khz to