Add ethtool support to configure the IRQ coalescing behavior. Support
separate timers for Rx and Tx for time based coalescing. For frame based
configuration, currently we only support the Rx side.
The hardware allows configuration of descriptor count instead of frame
count requiring conversion between the two. We assume 2 descriptors
per frame, one for the metadata and one for the data segment.
When rx-frames are not configured, we set the RX descriptor count to
half the ring size as a fail safe.
Default configuration:
ethtool -c eth0 | grep -E "rx-usecs:|tx-usecs:|rx-frames:"
rx-usecs: 30
rx-frames: 0
tx-usecs: 35
IRQ rate test:
With single iperf flow we monitor IRQ rate while changing the tx-usesc and
rx-usecs to high and low values.
ethtool -C eth0 rx-frames 8192 rx-usecs 150 tx-usecs 150
irq/sec 13k
irq/sec 14k
irq/sec 14k
ethtool -C eth0 rx-frames 8192 rx-usecs 10 tx-usecs 10
irq/sec 27k
irq/sec 28k
irq/sec 28k
Validating the use of extack:
ethtool -C eth0 rx-frames 16384
netlink error: fbnic: rx_frames is above device max
netlink error: Invalid argument
Signed-off-by: Mohsin Bashir <mohsin.bashr@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Brett Creeley <brett.creeley@amd.com>
Reviewed-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Link: https://patch.msgid.link/20250218023520.2038010-1-mohsin.bashr@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
7b5b7a597f