RE: [PATCH v3] net/mlx5: enable PCI related counters

[Raslan Darawsheh <rasland@nvidia.com>]

Hi,
> -----Original Message-----
> From: Wathsala Vithanage <wathsala.vithanage@arm.com>
> Sent: Thursday, February 15, 2024 8:27 PM
> To: NBU-Contact-Thomas Monjalon (EXTERNAL) <thomas@monjalon.net>;
> Dariusz Sosnowski <dsosnowski@nvidia.com>; Slava Ovsiienko
> <viacheslavo@nvidia.com>; Ori Kam <orika@nvidia.com>; Suanming Mou
> <suanmingm@nvidia.com>; Matan Azrad <matan@nvidia.com>
> Cc: dev@dpdk.org; nd@arm.com; Wathsala Vithanage
> <wathsala.vithanage@arm.com>; Honnappa Nagarahalli
> <honnappa.nagarahalli@arm.com>
> Subject: [PATCH v3] net/mlx5: enable PCI related counters
> 
> Versions of Mellanox NICs starting from CX5 have device counters related to
> PCI. These counters are helpful in debugging IO bottlenecks. For instance, the
> outbound_pci_stalled_rd and outbound_pci_stalled_wr counters can help
> with identifying NIC stalls due to insufficient PCI credits, which otherwise
> would have required a PCI analyzer or a sophisticated PCI root port with a
> PMU.
> Currently none of these are available in the MLX5 PMD even though ethtool is
> capable of reading some of them.
> Since PMD uses the same ioctl used by ethtool (SIOCETHTOOL) and reads via
> the kernel driver it is possible to add support with ease.
> There is one more PCI related counter and a device counter that aren't
> implemented in the Linux driver at the moment. These two are named
> outbound_pci_buffer_overflow and dev_out_of_buffer respectively. As per
> Nvidia's documentation these two counters can tell the number of packets
> dropped due to pci buffer overflow and the number of times the device
> owned queue had not enough buffers allocated.
> 
> Signed-off-by: Wathsala Vithanage <wathsala.vithanage@arm.com>
> Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
> Acked-by: Dariusz Sosnowski <dsosnowski@nvidia.com>
Patch applied to next-net-mlx,
Kindest regards
Raslan Darawsheh