[dpdk-dev] [PATCH] net/bnx2x: Fix transmit queue free threshold

[Charles (Chas) Williams]

The default tx_free_thresh is potentially larger than the allocated queue
which will result in TX queue cleanup never happening.  To fix this,
lower the default free threshold and ensure that the free threshold is
never greater than the maximum outstanding transmit buffers.

Fixes: 827ed2a118cc ("net/bnx2x: restructure Tx routine")

Signed-off-by: Chas Williams <ciwillia at brocade.com>
---
 drivers/net/bnx2x/bnx2x_rxtx.c | 2 ++
 drivers/net/bnx2x/bnx2x_rxtx.h | 2 +-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/bnx2x/bnx2x_rxtx.c b/drivers/net/bnx2x/bnx2x_rxtx.c
index 170e48f..adf0309 100644
--- a/drivers/net/bnx2x/bnx2x_rxtx.c
+++ b/drivers/net/bnx2x/bnx2x_rxtx.c
@@ -273,6 +273,8 @@ bnx2x_dev_tx_queue_setup(struct rte_eth_dev *dev,
 
 	txq->tx_free_thresh = tx_conf->tx_free_thresh ?
 		tx_conf->tx_free_thresh : DEFAULT_TX_FREE_THRESH;
+	txq->tx_free_thresh = min(txq->tx_free_thresh,
+				  txq->nb_tx_desc - BDS_PER_TX_PKT);
 
 	PMD_INIT_LOG(DEBUG, "fp[%02d] req_bd=%u, thresh=%u, usable_bd=%lu, "
 		     "total_bd=%lu, tx_pages=%u",
diff --git a/drivers/net/bnx2x/bnx2x_rxtx.h b/drivers/net/bnx2x/bnx2x_rxtx.h
index dd251aa..2e38ec2 100644
--- a/drivers/net/bnx2x/bnx2x_rxtx.h
+++ b/drivers/net/bnx2x/bnx2x_rxtx.h
@@ -11,7 +11,7 @@
 #ifndef _BNX2X_RXTX_H_
 #define _BNX2X_RXTX_H_
 
-#define DEFAULT_TX_FREE_THRESH   512
+#define DEFAULT_TX_FREE_THRESH   64
 #define RTE_PMD_BNX2X_TX_MAX_BURST 1
 
 /**
-- 
2.1.4