diff mbox series

[net-next,6/7] dpaa2-eth: Add congestion group taildrop

Message ID 20200515165300.16125-7-ioana.ciornei@nxp.com
State Changes Requested
Delegated to: David Miller
Headers show
Series dpaa2-eth: add support for Rx traffic classes | expand

Commit Message

Ioana Ciornei May 15, 2020, 4:52 p.m. UTC 
From: Ioana Radulescu <ruxandra.radulescu@nxp.com>

The increase in number of ingress frame queues means we now risk
depleting the buffer pool before the FQ taildrop kicks in.

Congestion group taildrop allows us to control the number of frames
that can accumulate on a group of Rx frame queues belonging to the
same traffic class.

This setting coexists with the frame queue based taildrop: whichever
limit gets hit first triggers the frame drop.

Signed-off-by: Ioana Radulescu <ruxandra.radulescu@nxp.com>
Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
---
 drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c | 16 ++++++++++++++++
 drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h |  9 +++++++++
 2 files changed, 25 insertions(+)
diff mbox series

Patch

diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
index 3cdfc564a45c..624f0e4bdc6c 100644
--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
@@ -1309,6 +1309,22 @@  static void dpaa2_eth_set_rx_taildrop(struct dpaa2_eth_priv *priv,
 		}
 	}
 
+	/* Congestion group taildrop: threshold is in frames, per group
+	 * of FQs belonging to the same traffic class
+	 */
+	td.threshold = DPAA2_ETH_CG_TAILDROP_THRESH(priv);
+	td.units = DPNI_CONGESTION_UNIT_FRAMES;
+	for (i = 0; i < dpaa2_eth_tc_count(priv); i++) {
+		err = dpni_set_taildrop(priv->mc_io, 0, priv->mc_token,
+					DPNI_CP_GROUP, DPNI_QUEUE_RX,
+					i, 0, &td);
+		if (err) {
+			netdev_err(priv->net_dev,
+				   "dpni_set_taildrop(CG) failed\n");
+			return;
+		}
+	}
+
 	priv->rx_td_enabled = td.enable;
 }
 
diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h
index 1b9f6689e9ec..184d5d83e497 100644
--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h
@@ -57,6 +57,15 @@ 
 #define DPAA2_ETH_REFILL_THRESH \
 	(DPAA2_ETH_NUM_BUFS - DPAA2_ETH_BUFS_PER_CMD)
 
+/* Congestion group taildrop threshold: number of frames allowed to accumulate
+ * at any moment in a group of Rx queues belonging to the same traffic class.
+ * Choose value such that we don't risk depleting the buffer pool before the
+ * 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))
+
 /* Maximum number of buffers that can be acquired/released through a single
  * QBMan command
  */