rte_eth_stats_get seems slow

[Morten Brørup]

Bruce,

rte_eth_stats_get() on Intel NICs seems slow to me.

E.g. getting the stats on a single port takes ~132 us (~451,000 CPU cycles) using the igb driver, and ~50 us using the i40e driver.

Referring to the igb driver source code [1], it's 44 calls to E1000_READ_REG(), so the math says that each one takes 3 us (~10,000 CPU cycles).

Is this expected behavior?

It adds up, e.g. it takes a full millisecond to fetch the stats from eight ports using the igb driver.

[1]: https://elixir.bootlin.com/dpdk/v24.11.1/source/drivers/net/e1000/igb_ethdev.c#L1724


Med venlig hilsen / Kind regards,
-Morten Brørup