diff mbox series

[v2,5/5] net/ena: prevent double doorbell

Message ID 20210126183226.2420903-6-mk@semihalf.com (mailing list archive)
State Accepted, archived
Delegated to: Ferruh Yigit
Headers
Series net/ena: minor bug fixes and improvements |

Checks

Context Check Description
ci/checkpatch success coding style OK
ci/iol-broadcom-Performance success Performance Testing PASS
ci/iol-broadcom-Functional success Functional Testing PASS
ci/Intel-compilation success Compilation OK
ci/iol-intel-Performance success Performance Testing PASS
ci/intel-Testing success Testing PASS
ci/iol-testing warning Testing issues

Commit Message

Michal Krawczyk Jan. 26, 2021, 6:32 p.m. UTC 
  From: Igor Chauskin <igorch@amazon.com>

Add per-tx-ring flag for packets that were pushed to HW but await
doorbell. That is to prevent a situation when a doorbell is sent due to
reaching Tx burst threshold and next send fails (e.g., due to queue
full). In such case we shouldn't send another doorbell because there are
no actual packets waiting for transmission.

Signed-off-by: Igor Chauskin <igorch@amazon.com>
Reviewed-by: Michal Krawczyk <mk@semihalf.com>
---
 drivers/net/ena/ena_ethdev.c | 7 +++++--
 drivers/net/ena/ena_ethdev.h | 4 ++++
 2 files changed, 9 insertions(+), 2 deletions(-)

Comments

Ferruh Yigit Jan. 29, 2021, 12:07 p.m. UTC | #1 
On 1/26/2021 6:32 PM, Michal Krawczyk wrote:
> From: Igor Chauskin <igorch@amazon.com>
> 
> Add per-tx-ring flag for packets that were pushed to HW but await
> doorbell. That is to prevent a situation when a doorbell is sent due to
> reaching Tx burst threshold and next send fails (e.g., due to queue
> full). In such case we shouldn't send another doorbell because there are
> no actual packets waiting for transmission.
> 
> Signed-off-by: Igor Chauskin <igorch@amazon.com>
> Reviewed-by: Michal Krawczyk <mk@semihalf.com>

Same here, can you please provide fixes line for the patch?
diff mbox series

Patch

diff --git a/drivers/net/ena/ena_ethdev.c b/drivers/net/ena/ena_ethdev.c
index 4083568d5d..8baec80040 100644
--- a/drivers/net/ena/ena_ethdev.c
+++ b/drivers/net/ena/ena_ethdev.c
@@ -1282,6 +1282,7 @@  static int ena_tx_queue_setup(struct rte_eth_dev *dev,
 	txq->ring_size = nb_desc;
 	txq->size_mask = nb_desc - 1;
 	txq->numa_socket_id = socket_id;
+	txq->pkts_without_db = false;
 
 	txq->tx_buffer_info = rte_zmalloc("txq->tx_buffer_info",
 					  sizeof(struct ena_tx_buffer) *
@@ -2522,6 +2523,7 @@  static int ena_xmit_mbuf(struct ena_ring *tx_ring, struct rte_mbuf *mbuf)
 			tx_ring->id);
 		ena_com_write_sq_doorbell(tx_ring->ena_com_io_sq);
 		tx_ring->tx_stats.doorbells++;
+		tx_ring->pkts_without_db = false;
 	}
 
 	/* prepare the packet's descriptors to dma engine */
@@ -2603,7 +2605,7 @@  static uint16_t eth_ena_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
 	for (sent_idx = 0; sent_idx < nb_pkts; sent_idx++) {
 		if (ena_xmit_mbuf(tx_ring, tx_pkts[sent_idx]))
 			break;
-
+		tx_ring->pkts_without_db = true;
 		rte_prefetch0(tx_pkts[ENA_IDX_ADD_MASKED(sent_idx, 4,
 			tx_ring->size_mask)]);
 	}
@@ -2612,10 +2614,11 @@  static uint16_t eth_ena_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
 		ena_com_free_q_entries(tx_ring->ena_com_io_sq);
 
 	/* If there are ready packets to be xmitted... */
-	if (sent_idx > 0) {
+	if (likely(tx_ring->pkts_without_db)) {
 		/* ...let HW do its best :-) */
 		ena_com_write_sq_doorbell(tx_ring->ena_com_io_sq);
 		tx_ring->tx_stats.doorbells++;
+		tx_ring->pkts_without_db = false;
 	}
 
 	ena_tx_cleanup(tx_ring);
diff --git a/drivers/net/ena/ena_ethdev.h b/drivers/net/ena/ena_ethdev.h
index 7bb74a1d06..ae235897ee 100644
--- a/drivers/net/ena/ena_ethdev.h
+++ b/drivers/net/ena/ena_ethdev.h
@@ -100,6 +100,10 @@  struct ena_ring {
 
 	enum ena_ring_type type;
 	enum ena_admin_placement_policy_type tx_mem_queue_type;
+
+	/* Indicate there are Tx packets pushed to the device and wait for db */
+	bool pkts_without_db;
+
 	/* Holds the empty requests for TX/RX OOO completions */
 	union {
 		uint16_t *empty_tx_reqs;