From: Jakub Kicinski <kuba@kernel.org>
To: Rahul Rameshbabu <rrameshbabu@nvidia.com>
Cc: Jacob Keller <jacob.e.keller@intel.com>,
Saeed Mahameed <saeed@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
Paolo Abeni <pabeni@redhat.com>,
Eric Dumazet <edumazet@google.com>,
Saeed Mahameed <saeedm@nvidia.com>, <netdev@vger.kernel.org>,
Tariq Toukan <tariqt@nvidia.com>, Gal Pressman <gal@nvidia.com>,
Richard Cochran <richardcochran@gmail.com>,
Vincent Cheng <vincent.cheng.xh@renesas.com>
Subject: Re: [net-next 03/15] net/mlx5: Add adjphase function to support hardware-only offset control
Date: Thu, 19 Jan 2023 21:45:16 -0800 [thread overview]
Message-ID: <20230119214516.59adab05@kernel.org> (raw)
In-Reply-To: <87k01hu6fb.fsf@nvidia.com>
On Thu, 19 Jan 2023 21:22:00 -0800 Rahul Rameshbabu wrote:
> > Hm, so are you saying that:
> >
> > adjtime(delta):
> > clock += delta
> >
> > but:
> >
> > adjfreq(delta):
>
> Did you mean adjphase here?
Yes, sorry
> > on clock tick & while delta > 0:
> > clock += small_value
> > delta -= small_value
> >
> > because from looking at mlx5 driver code its unclear whether the
> > implementation does a precise but one shot adjustment or gradual
> > adjustments.
>
> The pseudo code your drafted is accurate otherwise. The lack of clarity
> in our driver comes from leaving the responsibility of that smooth
> gradual transition (to keep in sync with the clock frequency while
> running) up to the device.
Ah, I see. That makes sense. This is how system clocks react too
or is it a local PTP invention? I think it may be worth documenting
in ptp_clock_kernel.h, most driver authors may not understand
the difference between adjtime and adjphase :(
next prev parent reply other threads:[~2023-01-20 5:45 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-18 18:35 [pull request][net-next 00/15] mlx5 updates 2023-01-18 Saeed Mahameed
2023-01-18 18:35 ` [net-next 01/15] net/mlx5e: Suppress Send WQEBB room warning for PAGE_SIZE >= 16KB Saeed Mahameed
2023-01-18 21:31 ` Jacob Keller
2023-01-20 4:00 ` patchwork-bot+netdevbpf
2023-01-18 18:35 ` [net-next 02/15] net/mlx5: Suppress error logging on UCTX creation Saeed Mahameed
2023-01-18 21:32 ` Jacob Keller
2023-01-18 18:35 ` [net-next 03/15] net/mlx5: Add adjphase function to support hardware-only offset control Saeed Mahameed
2023-01-18 21:33 ` Jacob Keller
2023-01-20 3:46 ` Jakub Kicinski
2023-01-20 3:56 ` Rahul Rameshbabu
2023-01-20 4:03 ` Jakub Kicinski
2023-01-20 4:26 ` Rahul Rameshbabu
2023-01-20 5:08 ` Jakub Kicinski
2023-01-20 5:22 ` Rahul Rameshbabu
2023-01-20 5:45 ` Jakub Kicinski [this message]
2023-01-20 6:02 ` Rahul Rameshbabu
2023-01-20 17:21 ` Jacob Keller
2023-01-20 18:00 ` Rahul Rameshbabu
2023-01-20 23:58 ` Jacob Keller
2023-01-21 0:06 ` Jakub Kicinski
2023-01-22 21:11 ` Rahul Rameshbabu
2023-01-23 2:22 ` Richard Cochran
2023-01-23 2:48 ` Rahul Rameshbabu
2023-01-23 2:58 ` Richard Cochran
2023-01-23 18:44 ` Rahul Rameshbabu
2023-01-23 19:13 ` Jacob Keller
2023-01-23 22:39 ` Richard Cochran
2023-01-23 22:36 ` Richard Cochran
2023-01-24 10:33 ` Bar Shapira
2023-01-24 19:15 ` Richard Cochran
2023-01-25 0:48 ` Jakub Kicinski
2023-01-25 2:26 ` Rahul Rameshbabu
2023-01-25 8:28 ` Gal Pressman
2023-01-23 2:15 ` Richard Cochran
2023-01-23 18:14 ` Jacob Keller
2023-01-18 18:35 ` [net-next 04/15] net/mlx5: Add hardware extended range support for PTP adjtime and adjphase Saeed Mahameed
2023-01-18 21:35 ` Jacob Keller
2023-01-18 18:35 ` [net-next 05/15] net/mlx5: E-switch, Remove redundant comment about meta rules Saeed Mahameed
2023-01-18 21:40 ` Jacob Keller
2023-01-18 18:35 ` [net-next 06/15] net/mlx5e: Fail with messages when params are not valid for XSK Saeed Mahameed
2023-01-18 21:41 ` Jacob Keller
2023-01-18 18:35 ` [net-next 07/15] net/mlx5e: Add warning when log WQE size is smaller than log stride size Saeed Mahameed
2023-01-18 21:42 ` Jacob Keller
2023-01-18 18:35 ` [net-next 08/15] net/mlx5e: TC, Pass flow attr to attach/detach mod hdr functions Saeed Mahameed
2023-01-18 21:42 ` Jacob Keller
2023-01-18 18:35 ` [net-next 09/15] net/mlx5e: TC, Add tc prefix to attach/detach " Saeed Mahameed
2023-01-18 21:44 ` Jacob Keller
2023-01-18 18:35 ` [net-next 10/15] net/mlx5e: TC, Use common function allocating flow mod hdr or encap mod hdr Saeed Mahameed
2023-01-18 21:45 ` Jacob Keller
2023-01-18 18:35 ` [net-next 11/15] net/mlx5e: Warn when destroying mod hdr hash table that is not empty Saeed Mahameed
2023-01-18 21:45 ` Jacob Keller
2023-01-18 18:35 ` [net-next 12/15] net/mlx5: E-Switch, Fix typo for egress Saeed Mahameed
2023-01-18 21:46 ` Jacob Keller
2023-01-18 18:36 ` [net-next 13/15] net/mlx5e: Support Geneve and GRE with VF tunnel offload Saeed Mahameed
2023-01-18 21:48 ` Jacob Keller
2023-01-18 18:36 ` [net-next 14/15] net/mlx5e: Remove redundant allocation of spec in create indirect fwd group Saeed Mahameed
2023-01-18 21:50 ` Jacob Keller
2023-01-18 18:36 ` [net-next 15/15] net/mlx5e: Use read lock for eswitch get callbacks Saeed Mahameed
2023-01-18 21:51 ` Jacob Keller
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