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From: Ido Schimmel <idosch@nvidia.com>
To: Richard Cochran <richardcochran@gmail.com>
Cc: netdev@vger.kernel.org, davem@davemloft.net, kuba@kernel.org,
	pabeni@redhat.com, edumazet@google.com, petrm@nvidia.com,
	amcohen@nvidia.com, danieller@nvidia.com, mlxsw@nvidia.com
Subject: Re: [PATCH net-next 0/9] mlxsw: Add PTP support for Spectrum-2 and newer ASICs
Date: Wed, 27 Jul 2022 17:48:36 +0300	[thread overview]
Message-ID: <YuFQRKIy9AxLcSz8@shredder> (raw)
In-Reply-To: <YuFGN/WBzVgae/cf@hoboy.vegasvil.org>

On Wed, Jul 27, 2022 at 07:05:43AM -0700, Richard Cochran wrote:
> On Wed, Jul 27, 2022 at 09:23:19AM +0300, Ido Schimmel wrote:
> 
> > Spectrum-2 and newer ASICs essentially implement a transparent clock
> > between all the switch ports, including the CPU port. The hardware will
> > generate the UTC time stamp for transmitted / received packets at the
> 
> The PTP time scale is TAI, not UTC.
> 
> > CPU port, but will compensate for forwarding delays in the ASIC by
> > adjusting the correction field in the PTP header (for PTP events) at the
> > ingress and egress ports.
> 
> If the switch adjusts this automatcally, then the time scale in use is
> not relevant.

It is adjusted automatically by hardware. Software only needs to enable
it.

  reply	other threads:[~2022-07-27 14:48 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-27  6:23 [PATCH net-next 0/9] mlxsw: Add PTP support for Spectrum-2 and newer ASICs Ido Schimmel
2022-07-27  6:23 ` [PATCH net-next 1/9] mlxsw: spectrum_ptp: Add helper functions to configure PTP traps Ido Schimmel
2022-07-27  6:23 ` [PATCH net-next 2/9] mlxsw: Support CQEv2 for SDQ in Spectrum-2 and newer ASICs Ido Schimmel
2022-07-27  6:23 ` [PATCH net-next 3/9] mlxsw: spectrum_ptp: Add PTP initialization / finalization for Spectrum-2 Ido Schimmel
2022-07-27  6:23 ` [PATCH net-next 4/9] mlxsw: Query UTC sec and nsec PCI offsets and values Ido Schimmel
2022-07-27  6:23 ` [PATCH net-next 5/9] mlxsw: spectrum_ptp: Add implementation for physical hardware clock operations Ido Schimmel
2022-07-27  6:23 ` [PATCH net-next 6/9] mlxsw: Send PTP packets as data packets to overcome a limitation Ido Schimmel
2022-07-27  6:23 ` [PATCH net-next 7/9] mlxsw: spectrum: Support time stamping on Spectrum-2 Ido Schimmel
2022-07-27  6:23 ` [PATCH net-next 8/9] mlxsw: spectrum_ptp: Support SIOCGHWTSTAMP, SIOCSHWTSTAMP ioctls Ido Schimmel
2022-07-27  6:23 ` [PATCH net-next 9/9] mlxsw: spectrum: Support ethtool 'get_ts_info' callback in Spectrum-2 Ido Schimmel
2022-07-27 14:05 ` [PATCH net-next 0/9] mlxsw: Add PTP support for Spectrum-2 and newer ASICs Richard Cochran
2022-07-27 14:48   ` Ido Schimmel [this message]
2022-07-27 14:16 ` Richard Cochran
2022-07-27 14:44   ` Ido Schimmel
2022-07-28  3:09     ` Richard Cochran
2022-07-28  7:03       ` Ido Schimmel
2022-07-29 10:30 ` patchwork-bot+netdevbpf

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