From: Mohammad Heib <[email protected]> This series makes the Flow Director ATR sample rate configurable at runtime through a devlink parameter.
On systems with many queues and high-rate TCP workloads, the fixed default sampling interval can cause frequent Flow Director reprogramming and TCP packet reordering. The optimal interval depends on the workload and system configuration. Patch 1 moves atr_sample_rate from per-ring to PF level, since it is a global policy. It also triggers a PF reset when re-enabling ATR via ethtool private flags so that fd_ena is reprogrammed in the TX queue HW context. Patch 2 exposes atr_sample_rate as a devlink runtime parameter so administrators can tune it without rebuilding the driver. Testing with iperf3 -t 60 showed ~7k TCP reordering events at the default sample rate (20). Setting atr_sample_rate to 10000 reduced reordering to ~769 (~90% reduction). Changes since v4: - Folded the PF reset patch into patch 1 for bisect cleanliness (was patch 3/3 in v4) - Skip PF reset when FD_SB (ntuple) already holds fd_ena high, avoiding unnecessary traffic disruption - Fix LLDP EEXIST path to not drop unrelated reset requests (reset_needed &= ~REBUILD_FLAG instead of = 0) - Flush existing ATR entries when setting atr_sample_rate to 0 via devlink, so stale filters do not persist on devices without HW ATR eviction - Documentation: clarify that the sampling interval is per Tx queue and counts TCP packets only; fix formatting Mohammad Heib (2): i40e: move ATR sample rate from ring to PF level i40e: add devlink parameter for Flow Director ATR sample rate Documentation/networking/devlink/i40e.rst | 21 +++++++++ drivers/net/ethernet/intel/i40e/i40e.h | 1 + .../net/ethernet/intel/i40e/i40e_devlink.c | 46 +++++++++++++++++++ .../net/ethernet/intel/i40e/i40e_ethtool.c | 12 ++++- drivers/net/ethernet/intel/i40e/i40e_main.c | 9 ++-- drivers/net/ethernet/intel/i40e/i40e_txrx.c | 6 ++- drivers/net/ethernet/intel/i40e/i40e_txrx.h | 3 +- 7 files changed, 87 insertions(+), 11 deletions(-) -- 2.56.0
