Re: [PATCH RFC 1/1] x86/paravirt: introduce param to disable pv sched_clock

2023-10-19 Thread Dongli Zhang
Hi Vitaly, Sean and David, On 10/19/23 08:40, Sean Christopherson wrote: > On Thu, Oct 19, 2023, Vitaly Kuznetsov wrote: >> Dongli Zhang writes: >> >>> As mentioned in the linux kernel development document, "sched_clock() is >>> used for scheduling and timestamping". While there is a default

Re: [PATCH RFC 1/1] x86/paravirt: introduce param to disable pv sched_clock

2023-10-19 Thread David Woodhouse
On Thu, 2023-10-19 at 08:40 -0700, Sean Christopherson wrote: > > > Normally, it should be up to the hypervisor to tell the guest which > > clock to use, i.e. if TSC is reliable or not. Let me put my question > > this way: if TSC on the particular host is good for everything, why > > does the

Re: [PATCH RFC 1/1] x86/paravirt: introduce param to disable pv sched_clock

2023-10-19 Thread Vitaly Kuznetsov
Dongli Zhang writes: > As mentioned in the linux kernel development document, "sched_clock() is > used for scheduling and timestamping". While there is a default native > implementation, many paravirtualizations have their own implementations. > > About KVM, it uses kvm_sched_clock_read() and

[PATCH RFC 1/1] x86/paravirt: introduce param to disable pv sched_clock

2023-10-18 Thread Dongli Zhang
As mentioned in the linux kernel development document, "sched_clock() is used for scheduling and timestamping". While there is a default native implementation, many paravirtualizations have their own implementations. About KVM, it uses kvm_sched_clock_read() and there is no way to only disable