Azure: mlx5e: Add support for PCI relaxed ordering (RO) for better performance

Bug #2039208 reported by Tim Gardner
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
linux-azure (Ubuntu)
Fix Released
Undecided
Unassigned
Jammy
In Progress
Medium
Tim Gardner
Lunar
In Progress
Medium
Tim Gardner

Bug Description

SRU Justification

[Impact]
On Azure, the VM SKU Standard_NC64as_T4_v3's bandwidth is 30 Gbps, but we can only reach 15~20 Gbps with the 5.15.0-1049-azure kernel in Ubuntu 20.04 or the 6.2.0-1014-azure kernel in Ubuntu 22.04.

After I pick up the upstream patch(es) to enable PCI relaxed ordering (RO) for the Mellanox VF NIC, the throughput goes up to 30.4 Gbps.

[Fix]

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=17347d5430c4e4e1a3c58ffa2732746bd26a9c02

[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e2351e517068718724f1d3b4010e2a41ec91fa76

[3] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=77528e2aed9246cf8017b8a6f1b658a264d6f2b2

[4] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ed4b0661cce119870edb1994fd06c9cbc1dc05c3

[Test Plan]

Microsoft tested

[Regression Potential]

Mellanox connections could be corrupted or run slower.

[Other Info]

SF: #00370735

Tim Gardner (timg-tpi)
affects: linux (Ubuntu) → linux-azure (Ubuntu)
Changed in linux-azure (Ubuntu):
status: New → Fix Released
description: updated
Revision history for this message
Tim Gardner (timg-tpi) wrote :
Changed in linux-azure (Ubuntu Jammy):
assignee: nobody → Tim Gardner (timg-tpi)
importance: Undecided → Medium
status: New → In Progress
Changed in linux-azure (Ubuntu Lunar):
assignee: nobody → Tim Gardner (timg-tpi)
importance: Undecided → Medium
status: New → In Progress
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