diff options
Diffstat (limited to 'drivers/net/ethernet/intel/fm10k/fm10k_main.c')
| -rw-r--r-- | drivers/net/ethernet/intel/fm10k/fm10k_main.c | 52 |
1 files changed, 40 insertions, 12 deletions
diff --git a/drivers/net/ethernet/intel/fm10k/fm10k_main.c b/drivers/net/ethernet/intel/fm10k/fm10k_main.c index 21d49550935e..d422cd187101 100644 --- a/drivers/net/ethernet/intel/fm10k/fm10k_main.c +++ b/drivers/net/ethernet/intel/fm10k/fm10k_main.c @@ -1363,7 +1363,7 @@ static bool fm10k_clean_tx_irq(struct fm10k_q_vector *q_vector, **/ static void fm10k_update_itr(struct fm10k_ring_container *ring_container) { - unsigned int avg_wire_size, packets; + unsigned int avg_wire_size, packets, itr_round; /* Only update ITR if we are using adaptive setting */ if (!ITR_IS_ADAPTIVE(ring_container->itr)) @@ -1375,18 +1375,44 @@ static void fm10k_update_itr(struct fm10k_ring_container *ring_container) avg_wire_size = ring_container->total_bytes / packets; - /* Add 24 bytes to size to account for CRC, preamble, and gap */ - avg_wire_size += 24; - - /* Don't starve jumbo frames */ - if (avg_wire_size > 3000) - avg_wire_size = 3000; + /* The following is a crude approximation of: + * wmem_default / (size + overhead) = desired_pkts_per_int + * rate / bits_per_byte / (size + ethernet overhead) = pkt_rate + * (desired_pkt_rate / pkt_rate) * usecs_per_sec = ITR value + * + * Assuming wmem_default is 212992 and overhead is 640 bytes per + * packet, (256 skb, 64 headroom, 320 shared info), we can reduce the + * formula down to + * + * (34 * (size + 24)) / (size + 640) = ITR + * + * We first do some math on the packet size and then finally bitshift + * by 8 after rounding up. We also have to account for PCIe link speed + * difference as ITR scales based on this. + */ + if (avg_wire_size <= 360) { + /* Start at 250K ints/sec and gradually drop to 77K ints/sec */ + avg_wire_size *= 8; + avg_wire_size += 376; + } else if (avg_wire_size <= 1152) { + /* 77K ints/sec to 45K ints/sec */ + avg_wire_size *= 3; + avg_wire_size += 2176; + } else if (avg_wire_size <= 1920) { + /* 45K ints/sec to 38K ints/sec */ + avg_wire_size += 4480; + } else { + /* plateau at a limit of 38K ints/sec */ + avg_wire_size = 6656; + } - /* Give a little boost to mid-size frames */ - if ((avg_wire_size > 300) && (avg_wire_size < 1200)) - avg_wire_size /= 3; - else - avg_wire_size /= 2; + /* Perform final bitshift for division after rounding up to ensure + * that the calculation will never get below a 1. The bit shift + * accounts for changes in the ITR due to PCIe link speed. + */ + itr_round = ACCESS_ONCE(ring_container->itr_scale) + 8; + avg_wire_size += (1 << itr_round) - 1; + avg_wire_size >>= itr_round; /* write back value and retain adaptive flag */ ring_container->itr = avg_wire_size | FM10K_ITR_ADAPTIVE; @@ -1604,6 +1630,7 @@ static int fm10k_alloc_q_vector(struct fm10k_intfc *interface, q_vector->tx.ring = ring; q_vector->tx.work_limit = FM10K_DEFAULT_TX_WORK; q_vector->tx.itr = interface->tx_itr; + q_vector->tx.itr_scale = interface->hw.mac.itr_scale; q_vector->tx.count = txr_count; while (txr_count) { @@ -1632,6 +1659,7 @@ static int fm10k_alloc_q_vector(struct fm10k_intfc *interface, /* save Rx ring container info */ q_vector->rx.ring = ring; q_vector->rx.itr = interface->rx_itr; + q_vector->rx.itr_scale = interface->hw.mac.itr_scale; q_vector->rx.count = rxr_count; while (rxr_count) { |