[PATCH v2 0/4] nvme-cli: NIC topology aware I/O queue scaling

[Nilay Shroff]

Hi,

This series is a rework of the earlier patchset[1]. The main
difference is that --nr-io-queues is now calculated in nvme-cli
instead of in the kernel when establishing an NVMe/TCP connection.

This rework is based on the feedback received[2] from the netdev
maintainers.

The original patchset determined the number of NVMe/TCP I/O queues
based on the number of online CPUs and the number of hardware queues
available on the NIC in kernel driver. This series moves that logic
to nvme-cli.

When --nr-io-queues is not explicitly specified, nvme-cli determines
the egress netdev for the NVMe/TCP connection, retrieves its current
hardware queue count, and calculates the default as:

	min(nr_hw_queues, num_online_cpus)

If nr_hw_queues cannot be retrieved, or the NIC only supports one
hardware queue, do not calculate nr-io-queues and let the host
determine the value.

The remaining patches from the original series, which expose NVMe/TCP
queue and flow information through debugfs, are still useful for
subsequent CPU/NIC topology tuning. I will send those changes as a
separate patchset.

The two patchsets are independent and can be reviewed and merged
separately.

As usual, comments, feedback, and suggestions are most welcome!

Thanks!

[1] https://lore.kernel.org/all/20260731073918.614014-1-nilay@linux.ibm.com/
[2] https://lore.kernel.org/all/20260807160904.2eb1b3d1@kernel.org/

Changes since v1:
  - Added new patch 3/4 for covering unit test cases for 
    shr_route_get_egress_iface() and shr_netdev_get_hw_queues()
    helpers (Daniel Wagner)
  - If nr_hw_queues cannot be retrieved, or the NIC only supports
    one hardware queue, do not calculate nr-io-queues and let the
    host determine the value.

Nilay Shroff (4):
  shared/net-util-linux: add support for retrieving egress netdev
  shared/net-util-linux: add support for retrieving NIC h/w queues
  shared: add more test coverage for net-util
  fabrics: determine --nr-io-queues when not explicitly specified

 shared/net-util-linux.c      | 265 +++++++++++++++++++++++++++++++++++
 shared/net-util.h            |  32 +++++
 shared/tests/test-net-util.c | 117 ++++++++++++++++
 src/fabrics.c                |  79 ++++++++++-
 4 files changed, 490 insertions(+), 3 deletions(-)

-- 
2.53.0