From 3f8b826d705fc6f0f0602fcbe6ee3b646ed3316e Mon Sep 17 00:00:00 2001 From: Ioana Radulescu Date: Sun, 31 May 2020 00:08:12 +0300 Subject: dpaa2-eth: Update FQ taildrop threshold and buffer pool count Now that we have congestion group taildrop configured at all times, we can afford to increase the frame queue taildrop threshold; this will ensure a better response when receiving bursts of large-sized frames. Also decouple the buffer pool count from the Rx FQ taildrop threshold, as above change would increase it too much. Instead, keep the old count as a hardcoded value. With the new limits, we try to ensure that: * we allow enough leeway for large frame bursts (by buffering enough of them in queues to avoid heavy dropping in case of bursty traffic, but when overall ingress bandwidth is manageable) * allow pending frames to be evenly spread between ingress FQs, regardless of frame size * avoid dropping frames due to the buffer pool being empty; this is not a bad behaviour per se, but system overall response is more linear and predictable when frames are dropped at frame queue/group level. Signed-off-by: Ioana Radulescu Signed-off-by: Ioana Ciornei Signed-off-by: David S. Miller --- drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h | 23 +++++++++++------------ 1 file changed, 11 insertions(+), 12 deletions(-) (limited to 'drivers/net') diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h index 184d5d83e497..02c0eea69a23 100644 --- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h +++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h @@ -36,24 +36,24 @@ /* Convert L3 MTU to L2 MFL */ #define DPAA2_ETH_L2_MAX_FRM(mtu) ((mtu) + VLAN_ETH_HLEN) -/* Set the taildrop threshold (in bytes) to allow the enqueue of several jumbo - * frames in the Rx queues (length of the current frame is not - * taken into account when making the taildrop decision) +/* Set the taildrop threshold (in bytes) to allow the enqueue of a large + * enough number of jumbo frames in the Rx queues (length of the current + * frame is not taken into account when making the taildrop decision) */ -#define DPAA2_ETH_FQ_TAILDROP_THRESH (64 * 1024) +#define DPAA2_ETH_FQ_TAILDROP_THRESH (1024 * 1024) /* Maximum number of Tx confirmation frames to be processed * in a single NAPI call */ #define DPAA2_ETH_TXCONF_PER_NAPI 256 -/* Buffer quota per queue. Must be large enough such that for minimum sized - * frames taildrop kicks in before the bpool gets depleted, so we compute - * how many 64B frames fit inside the taildrop threshold and add a margin - * to accommodate the buffer refill delay. +/* Buffer qouta per channel. We want to keep in check number of ingress frames + * in flight: for small sized frames, congestion group taildrop may kick in + * first; for large sizes, Rx FQ taildrop threshold will ensure only a + * reasonable number of frames will be pending at any given time. + * Ingress frame drop due to buffer pool depletion should be a corner case only */ -#define DPAA2_ETH_MAX_FRAMES_PER_QUEUE (DPAA2_ETH_FQ_TAILDROP_THRESH / 64) -#define DPAA2_ETH_NUM_BUFS (DPAA2_ETH_MAX_FRAMES_PER_QUEUE + 256) +#define DPAA2_ETH_NUM_BUFS 1280 #define DPAA2_ETH_REFILL_THRESH \ (DPAA2_ETH_NUM_BUFS - DPAA2_ETH_BUFS_PER_CMD) @@ -63,8 +63,7 @@ * taildrop kicks in */ #define DPAA2_ETH_CG_TAILDROP_THRESH(priv) \ - (DPAA2_ETH_MAX_FRAMES_PER_QUEUE * dpaa2_eth_queue_count(priv) / \ - dpaa2_eth_tc_count(priv)) + (1024 * dpaa2_eth_queue_count(priv) / dpaa2_eth_tc_count(priv)) /* Maximum number of buffers that can be acquired/released through a single * QBMan command -- cgit v1.2.3-59-g8ed1b