Commit 3f8b826d authored by Ioana Radulescu's avatar Ioana Radulescu Committed by David S. Miller
Browse files

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: default avatarIoana Radulescu <ruxandra.radulescu@nxp.com>
Signed-off-by: default avatarIoana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2c8d1c8d

drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h

+11 −12
Original line number Diff line number Diff line
@@ -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

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