On Fri, 9 Feb 2024 20:41:42 +0000 Wathsala Vithanage <[email protected]> wrote:
> 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 <[email protected]> > Reviewed-by: Honnappa Nagarahalli <[email protected]> Would it be possible to do this at PCI bus layer so all PCI devices have that feature?
