> On Jan 18, 2017, at 05:43, Miroslav Lichvar <mlich...@redhat.com> wrote:
> Denny,
> 
> there is apparently a new ioctl for measuring the offset between the
> NIC clock and system clock, which is supported on some onboard NICs
> (that share clock with the CPU?). It's called PTP_SYS_OFFSET_PRECISE
> and if I understand how it works correctly, it should solve all these
> problems with delay and asymmetry. Is it supported on the i211 or
> i350?


Miroslav,

Unfortunately, no. PTP_SYS_OFFSET_PRECISE uses PCIE_PTM (Precise Time 
Measurement) which requires newer PCIe chipsets. I don’t have a system that 
supports PTM. Best that I can tell, the only Ethernet driver in the kernel that 
currently offers PTM support is the Intel PCI-Express pro/1000 (E1000E), and I 
don’t have one of those either. Otherwise I would have added support for it in 
ethtscal. :)

https://pcisig.com/sites/default/files/specification_documents/ECN_PTM_Revision1a_31_Mar_2013.pdf
 
<https://pcisig.com/sites/default/files/specification_documents/ECN_PTM_Revision1a_31_Mar_2013.pdf>

Denny

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