linux-kernel - [PATCH net-next V3 0/3] mlx5 PTM cross timestamping support

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Message-ID: <20240730134055.1835261-1-tariqt@nvidia.com>
Date: Tue, 30 Jul 2024 16:40:51 +0300
From: Tariq Toukan <tariqt@...dia.com>
To: "David S. Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>, Eric Dumazet <edumazet@...gle.com>
CC: <netdev@...r.kernel.org>, Saeed Mahameed <saeedm@...dia.com>, Gal Pressman
	<gal@...dia.com>, Leon Romanovsky <leonro@...dia.com>, John Stultz
	<jstultz@...gle.com>, Thomas Gleixner <tglx@...utronix.de>, "Anna-Maria
 Behnsen" <anna-maria@...utronix.de>, Frederic Weisbecker
	<frederic@...nel.org>, <linux-kernel@...r.kernel.org>, Bjorn Helgaas
	<bhelgaas@...gle.com>, <linux-pci@...r.kernel.org>, Ingo Molnar
	<mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, Dave Hansen
	<dave.hansen@...ux.intel.com>, <x86@...nel.org>, Carolina Jubran
	<cjubran@...dia.com>, Bar Shapira <bshapira@...dia.com>, Rahul Rameshbabu
	<rrameshbabu@...dia.com>, Tariq Toukan <tariqt@...dia.com>
Subject: [PATCH net-next V3 0/3] mlx5 PTM cross timestamping support

Hi,

This is V3. You can find V2 as part of a larger series here:
https://lore.kernel.org/netdev/d1dba3e1-2ecc-4fdf-a23b-7696c4bccf45@gmail.com/T/

This patchset by Rahul and Carolina adds PTM (Precision Time Measurement)
support to the mlx5 driver.

PTM is a PCI extended capability introduced by PCI-SIG for providing an
accurate read of the device clock offset without being impacted by
asymmetric bus transfer rates.

The performance of PTM on ConnectX-7 was evaluated using both real-time
(RTC) and free-running (FRC) clocks under traffic and no traffic
conditions. Tests with phc2sys measured the maximum offset values at a 50Hz
rate, with and without PTM. 

Results:

1. No traffic
+-----+--------+--------+
|     | No-PTM | PTM    |
+-----+--------+--------+
| FRC | 125 ns | <29 ns |
+-----+--------+--------+
| RTC | 248 ns | <34 ns |
+-----+--------+--------+

2. With traffic
+-----+--------+--------+
|     | No-PTM | PTM    |
+-----+--------+--------+
| FRC | 254 ns | <40 ns |
+-----+--------+--------+
| RTC | 255 ns | <45 ns |
+-----+--------+--------+


Series generated against:
commit 1722389b0d86 ("Merge tag 'net-6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net")

Thanks,
Tariq.

V3:
- Rebased on latest. As a result, had to replace the call to the recently
  removed function convert_art_ns_to_tsc().
- Added more CCs to the series per Jakub's feedback.
- Added perf numbers.


Carolina Jubran (1):
  net/mlx5: Add support for enabling PTM PCI capability

Rahul Rameshbabu (2):
  net/mlx5: Add support for MTPTM and MTCTR registers
  net/mlx5: Implement PTM cross timestamping support

 drivers/net/ethernet/mellanox/mlx5/core/fw.c  |  1 +
 .../ethernet/mellanox/mlx5/core/lib/clock.c   | 91 +++++++++++++++++++
 .../net/ethernet/mellanox/mlx5/core/main.c    |  6 ++
 include/linux/mlx5/device.h                   |  7 +-
 include/linux/mlx5/driver.h                   |  2 +
 include/linux/mlx5/mlx5_ifc.h                 | 43 +++++++++
 6 files changed, 149 insertions(+), 1 deletion(-)

-- 
2.44.0