Re: [patch 5/5] PTP: add kvm PTP driver

2017-01-21 Thread Paolo Bonzini
On 20/01/2017 19:08, Radim Krcmar wrote: > 2017-01-20 13:00-0200, Marcelo Tosatti: >> On Fri, Jan 20, 2017 at 03:12:56PM +0100, Radim Krcmar wrote: >>> 2017-01-20 10:20-0200, Marcelo Tosatti: + do { + /* + * We are measuring the delay between + *

Re: [patch 5/5] PTP: add kvm PTP driver

2017-01-21 Thread Paolo Bonzini
On 20/01/2017 19:08, Radim Krcmar wrote: > 2017-01-20 13:00-0200, Marcelo Tosatti: >> On Fri, Jan 20, 2017 at 03:12:56PM +0100, Radim Krcmar wrote: >>> 2017-01-20 10:20-0200, Marcelo Tosatti: + do { + /* + * We are measuring the delay between + *

Re: [patch 5/5] PTP: add kvm PTP driver

2017-01-20 Thread Marcelo Tosatti
On Fri, Jan 20, 2017 at 07:08:49PM +0100, Radim Krcmar wrote: > 2017-01-20 13:00-0200, Marcelo Tosatti: > > On Fri, Jan 20, 2017 at 03:12:56PM +0100, Radim Krcmar wrote: > >> 2017-01-20 10:20-0200, Marcelo Tosatti: > >> > +do { > >> > +/* > >> > + * We are

Re: [patch 5/5] PTP: add kvm PTP driver

2017-01-20 Thread Marcelo Tosatti
On Fri, Jan 20, 2017 at 07:08:49PM +0100, Radim Krcmar wrote: > 2017-01-20 13:00-0200, Marcelo Tosatti: > > On Fri, Jan 20, 2017 at 03:12:56PM +0100, Radim Krcmar wrote: > >> 2017-01-20 10:20-0200, Marcelo Tosatti: > >> > +do { > >> > +/* > >> > + * We are

Re: [patch 5/5] PTP: add kvm PTP driver

2017-01-20 Thread Radim Krcmar
2017-01-20 13:00-0200, Marcelo Tosatti: > On Fri, Jan 20, 2017 at 03:12:56PM +0100, Radim Krcmar wrote: >> 2017-01-20 10:20-0200, Marcelo Tosatti: >> > + do { >> > + /* >> > + * We are measuring the delay between >> > + * kvm_hypercall and rdtsc using TSC, >> > +

Re: [patch 5/5] PTP: add kvm PTP driver

2017-01-20 Thread Radim Krcmar
2017-01-20 13:00-0200, Marcelo Tosatti: > On Fri, Jan 20, 2017 at 03:12:56PM +0100, Radim Krcmar wrote: >> 2017-01-20 10:20-0200, Marcelo Tosatti: >> > + do { >> > + /* >> > + * We are measuring the delay between >> > + * kvm_hypercall and rdtsc using TSC, >> > +

Re: [patch 5/5] PTP: add kvm PTP driver

2017-01-20 Thread Paolo Bonzini
On 20/01/2017 16:00, Marcelo Tosatti wrote: >>> + system_counter->cs = get_kvmclock_cs(); >> >> Can't we use clocksource_tsc and just pass the tsc without kvmclock in >> the middle? > > No, it has to be the kvmclock value. And that would be too tricky anyway. :) Paolo

Re: [patch 5/5] PTP: add kvm PTP driver

2017-01-20 Thread Paolo Bonzini
On 20/01/2017 16:00, Marcelo Tosatti wrote: >>> + system_counter->cs = get_kvmclock_cs(); >> >> Can't we use clocksource_tsc and just pass the tsc without kvmclock in >> the middle? > > No, it has to be the kvmclock value. And that would be too tricky anyway. :) Paolo

Re: [patch 5/5] PTP: add kvm PTP driver

2017-01-20 Thread Marcelo Tosatti
On Fri, Jan 20, 2017 at 03:12:56PM +0100, Radim Krcmar wrote: > 2017-01-20 10:20-0200, Marcelo Tosatti: > > Add a driver with gettime method returning hosts realtime clock. > > This allows Chrony to synchronize host and guest clocks with > > high precision (see results below). > > > > chronyc>

Re: [patch 5/5] PTP: add kvm PTP driver

2017-01-20 Thread Marcelo Tosatti
On Fri, Jan 20, 2017 at 03:12:56PM +0100, Radim Krcmar wrote: > 2017-01-20 10:20-0200, Marcelo Tosatti: > > Add a driver with gettime method returning hosts realtime clock. > > This allows Chrony to synchronize host and guest clocks with > > high precision (see results below). > > > > chronyc>

Re: [patch 5/5] PTP: add kvm PTP driver

2017-01-20 Thread Radim Krcmar
2017-01-20 15:12+0100, Radim Krcmar: > 2017-01-20 10:20-0200, Marcelo Tosatti: >> +spin_lock(_ptp_lock); > > What does the lock prevent? clock_off/clock_off_gpa. :)

Re: [patch 5/5] PTP: add kvm PTP driver

2017-01-20 Thread Radim Krcmar
2017-01-20 15:12+0100, Radim Krcmar: > 2017-01-20 10:20-0200, Marcelo Tosatti: >> +spin_lock(_ptp_lock); > > What does the lock prevent? clock_off/clock_off_gpa. :)

Re: [patch 5/5] PTP: add kvm PTP driver

2017-01-20 Thread Radim Krcmar
2017-01-20 10:20-0200, Marcelo Tosatti: > Add a driver with gettime method returning hosts realtime clock. > This allows Chrony to synchronize host and guest clocks with > high precision (see results below). > > chronyc> sources > MS Name/IP address Stratum Poll Reach LastRx Last sample

Re: [patch 5/5] PTP: add kvm PTP driver

2017-01-20 Thread Radim Krcmar
2017-01-20 10:20-0200, Marcelo Tosatti: > Add a driver with gettime method returning hosts realtime clock. > This allows Chrony to synchronize host and guest clocks with > high precision (see results below). > > chronyc> sources > MS Name/IP address Stratum Poll Reach LastRx Last sample

Re: [patch 5/5] PTP: add kvm PTP driver

2017-01-20 Thread Marcelo Tosatti
On Fri, Jan 20, 2017 at 01:58:33PM +0100, Paolo Bonzini wrote: > > > On 20/01/2017 13:20, Marcelo Tosatti wrote: > > + ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING, > > +clock_off_gpa, > > +KVM_CLOCK_PAIRING_WALLCLOCK); > > +

Re: [patch 5/5] PTP: add kvm PTP driver

2017-01-20 Thread Marcelo Tosatti
On Fri, Jan 20, 2017 at 01:58:33PM +0100, Paolo Bonzini wrote: > > > On 20/01/2017 13:20, Marcelo Tosatti wrote: > > + ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING, > > +clock_off_gpa, > > +KVM_CLOCK_PAIRING_WALLCLOCK); > > +

Re: [patch 5/5] PTP: add kvm PTP driver

2017-01-20 Thread Paolo Bonzini
On 20/01/2017 13:20, Marcelo Tosatti wrote: > + ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING, > + clock_off_gpa, > + KVM_CLOCK_PAIRING_WALLCLOCK); > + if (ret != 0) { > + pr_err("clock

Re: [patch 5/5] PTP: add kvm PTP driver

2017-01-20 Thread Paolo Bonzini
On 20/01/2017 13:20, Marcelo Tosatti wrote: > + ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING, > + clock_off_gpa, > + KVM_CLOCK_PAIRING_WALLCLOCK); > + if (ret != 0) { > + pr_err("clock