Re: [RFC PATCH v4] ptp: Add vDSO-style vmclock support

2024-07-17 Thread David Woodhouse
On Tue, 2024-07-16 at 15:20 +0200, Peter Hilber wrote: > On 16.07.24 14:32, David Woodhouse wrote: > > On 16 July 2024 12:54:52 BST, Peter Hilber > > wrote: > > > On 11.07.24 09:50, David Woodhouse wrote: > > > > On Thu, 2024-07-11 at 09:25 +0200, Peter Hilber wrote: > > > > > > > > > > IMHO

Re: [RFC PATCH v4] ptp: Add vDSO-style vmclock support

2024-07-17 Thread David Woodhouse
On Tue, 2024-07-16 at 13:54 +0200, Peter Hilber wrote: > On 08.07.24 11:27, David Woodhouse wrote: > > + > > +   /* > > +    * Time according to time_type field above. > > +    */ > > +   uint64_t time_sec;  /* Seconds since time_type epoch */ > > +   uint64_t

Re: [RFC PATCH v4] ptp: Add vDSO-style vmclock support

2024-07-16 Thread Peter Hilber
On 16.07.24 14:32, David Woodhouse wrote: > On 16 July 2024 12:54:52 BST, Peter Hilber > wrote: >> On 11.07.24 09:50, David Woodhouse wrote: >>> On Thu, 2024-07-11 at 09:25 +0200, Peter Hilber wrote: IMHO this phrasing is better, since it directly refers to the state of the

Re: [RFC PATCH v4] ptp: Add vDSO-style vmclock support

2024-07-16 Thread David Woodhouse
On 16 July 2024 12:54:52 BST, Peter Hilber wrote: >On 11.07.24 09:50, David Woodhouse wrote: >> On Thu, 2024-07-11 at 09:25 +0200, Peter Hilber wrote: >>> >>> IMHO this phrasing is better, since it directly refers to the state of the >>> structure. >> >> Thanks. I'll update it. >> >>> AFAIU if

Re: [RFC PATCH v4] ptp: Add vDSO-style vmclock support

2024-07-16 Thread Peter Hilber
On 08.07.24 11:27, David Woodhouse wrote: > + > + /* > + * Time according to time_type field above. > + */ > + uint64_t time_sec; /* Seconds since time_type epoch */ > + uint64_t time_frac_sec; /* (seconds >> 64) */ > + uint64_t time_esterror_picosec;

Re: [RFC PATCH v4] ptp: Add vDSO-style vmclock support

2024-07-16 Thread Peter Hilber
On 11.07.24 09:50, David Woodhouse wrote: > On Thu, 2024-07-11 at 09:25 +0200, Peter Hilber wrote: >> >> IMHO this phrasing is better, since it directly refers to the state of the >> structure. > > Thanks. I'll update it. > >> AFAIU if there would be abnormal delays in store buffers, causing

Re: [RFC PATCH v4] ptp: Add vDSO-style vmclock support

2024-07-11 Thread David Woodhouse
On Thu, 2024-07-11 at 09:25 +0200, Peter Hilber wrote: > > IMHO this phrasing is better, since it directly refers to the state of the > structure. Thanks. I'll update it. > AFAIU if there would be abnormal delays in store buffers, causing some > driver to still see the old clock for some time,

Re: [RFC PATCH v4] ptp: Add vDSO-style vmclock support

2024-07-11 Thread Peter Hilber
On 10.07.24 18:01, David Woodhouse wrote: > On Wed, 2024-07-10 at 15:07 +0200, Peter Hilber wrote: >> On 08.07.24 11:27, David Woodhouse wrote: >>> From: David Woodhouse >>> >>> The vmclock "device" provides a shared memory region with precision clock >>> information. By using shared memory, it

Re: [RFC PATCH v4] ptp: Add vDSO-style vmclock support

2024-07-10 Thread David Woodhouse
On Wed, 2024-07-10 at 15:07 +0200, Peter Hilber wrote: > On 08.07.24 11:27, David Woodhouse wrote: > > From: David Woodhouse > > > > The vmclock "device" provides a shared memory region with precision clock > > information. By using shared memory, it is safe across Live Migration. > > > > Like

Re: [RFC PATCH v4] ptp: Add vDSO-style vmclock support

2024-07-10 Thread Peter Hilber
On 08.07.24 11:27, David Woodhouse wrote: > From: David Woodhouse > > The vmclock "device" provides a shared memory region with precision clock > information. By using shared memory, it is safe across Live Migration. > > Like the KVM PTP clock, this can convert TSC-based cross timestamps into >

[RFC PATCH v4] ptp: Add vDSO-style vmclock support

2024-07-08 Thread David Woodhouse
From: David Woodhouse The vmclock "device" provides a shared memory region with precision clock information. By using shared memory, it is safe across Live Migration. Like the KVM PTP clock, this can convert TSC-based cross timestamps into KVM clock values. Unlike the KVM PTP clock, it does so