tree cb1429713cc1e92b871de63978e027ed5566470a
parent 45bd634131fd17d5761876e09f81b921534bc2c4
author Petr Machata <petrm@mellanox.com> 1567007677 +0300
committer David S. Miller <davem@davemloft.net> 1567041844 -0700

mlxsw: spectrum_ptp: Add counters for GC events

On Spectrum-1, timestamped PTP packets and the corresponding timestamps need to
be kept in caches until both are available, at which point they are matched up
and packets forwarded as appropriate. However, not all packets will ever see
their timestamp, and not all timestamps will ever see their packet. It is
necessary to dispose of such abandoned entries, so a garbage collector was
introduced in commit 5d23e4159772 ("mlxsw: spectrum: PTP: Garbage-collect
unmatched entries").

If these GC events happen often, it is a sign of a problem. However because this
whole mechanism is taking place behind the scenes, there is no direct way to
determine whether garbage collection took place.

Therefore to fix this, on Spectrum-1 only, expose four artificial ethtool
counters for the GC events: GCd timestamps and packets, in TX and RX directions.

Cc: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>