From ec837ad0fc7c6df4912cc2706b9cd54b225f4a34 Mon Sep 17 00:00:00 2001
From: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
Date: Tue, 22 Jun 2021 19:40:49 +0300
Subject: [PATCH] net/mlx5: fix multi-segment inline for the first segments
Before 19.08 release the Tx burst routines of mlx5 PMD
provided data inline for the first short segments of the
multi-segment packets. In the release 19.08 mlx5 Tx datapath
was refactored and this behavior was broken, affecting the
performance.
For example, the T-Rex traffic generator might use small
leading segments to handle packet headers and performance
degradation was noticed.
If the first segments of the multi-segment packet are short
and the overall length is below the inline threshold it
should be inline into the WQE to fix the performance.
Fixes: 18a1c20044c0 ("net/mlx5: implement Tx burst template")
Cc: stable@dpdk.org
Signed-off-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
---
drivers/net/mlx5/mlx5_tx.h | 28 +++++++++++++---------------
1 file changed, 13 insertions(+), 15 deletions(-)
diff --git a/drivers/net/mlx5/mlx5_tx.h b/drivers/net/mlx5/mlx5_tx.h
index 7d3ff8407c..634c9d754a 100644
--- a/drivers/net/mlx5/mlx5_tx.h
+++ b/drivers/net/mlx5/mlx5_tx.h
@@ -2040,6 +2040,8 @@ mlx5_tx_packet_multi_inline(struct mlx5_txq_data *__rte_restrict txq,
unsigned int nxlen;
uintptr_t start;
+ mbuf = loc->mbuf;
+ nxlen = rte_pktmbuf_data_len(mbuf);
/*
* Packet length exceeds the allowed inline data length,
* check whether the minimal inlining is required.
@@ -2049,28 +2051,23 @@ mlx5_tx_packet_multi_inline(struct mlx5_txq_data *__rte_restrict txq,
MLX5_ESEG_MIN_INLINE_SIZE);
MLX5_ASSERT(txq->inlen_mode <= txq->inlen_send);
inlen = txq->inlen_mode;
- } else {
- if (loc->mbuf->ol_flags & PKT_TX_DYNF_NOINLINE ||
- !vlan || txq->vlan_en) {
- /*
- * VLAN insertion will be done inside by HW.
- * It is not utmost effective - VLAN flag is
- * checked twice, but we should proceed the
- * inlining length correctly and take into
- * account the VLAN header being inserted.
- */
- return mlx5_tx_packet_multi_send
- (txq, loc, olx);
- }
+ } else if (vlan && !txq->vlan_en) {
+ /*
+ * VLAN insertion is requested and hardware does not
+ * support the offload, will do with software inline.
+ */
inlen = MLX5_ESEG_MIN_INLINE_SIZE;
+ } else if (mbuf->ol_flags & PKT_TX_DYNF_NOINLINE ||
+ nxlen > txq->inlen_send) {
+ return mlx5_tx_packet_multi_send(txq, loc, olx);
+ } else {
+ goto do_first;
}
/*
* Now we know the minimal amount of data is requested
* to inline. Check whether we should inline the buffers
* from the chain beginning to eliminate some mbufs.
*/
- mbuf = loc->mbuf;
- nxlen = rte_pktmbuf_data_len(mbuf);
if (unlikely(nxlen <= txq->inlen_send)) {
/* We can inline first mbuf at least. */
if (nxlen < inlen) {
@@ -2092,6 +2089,7 @@ mlx5_tx_packet_multi_inline(struct mlx5_txq_data *__rte_restrict txq,
goto do_align;
}
}
+do_first:
do {
inlen = nxlen;
mbuf = NEXT(mbuf);
--
2.39.5