On Fri, 25 Apr 2025 13:52:55 +0200 Morten Brørup <m...@smartsharesystems.com> wrote:
> 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 > Well reading each stat requires a PCI access. And PCI accesses are non-cached.
