git: c81f8c26115a - main - ena: Avoid unnecessary mbuf collapses for LLQ condition
Marcin Wojtas
mw at FreeBSD.org
Wed Sep 1 23:07:32 UTC 2021
The branch main has been updated by mw:
URL: https://cgit.FreeBSD.org/src/commit/?id=c81f8c26115a64b9a97ecdb2a64e824dd839ee73
commit c81f8c26115a64b9a97ecdb2a64e824dd839ee73
Author: Artur Rojek <ar at semihalf.com>
AuthorDate: 2021-08-12 08:34:17 +0000
Commit: Marcin Wojtas <mw at FreeBSD.org>
CommitDate: 2021-09-01 23:05:38 +0000
ena: Avoid unnecessary mbuf collapses for LLQ condition
In case of Low-latency Queue, one small enough descriptor can be pushed
directly to the ENA hw, thus saving one fragment. Check for this
condition before performing collapse.
Obtained from: Semihalf
MFC after: 2 weeks
Sponsored by: Amazon, Inc.
---
sys/dev/ena/ena_datapath.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/sys/dev/ena/ena_datapath.c b/sys/dev/ena/ena_datapath.c
index 15bd09c489cf..c0066b1209cc 100644
--- a/sys/dev/ena/ena_datapath.c
+++ b/sys/dev/ena/ena_datapath.c
@@ -801,6 +801,11 @@ ena_check_and_collapse_mbuf(struct ena_ring *tx_ring, struct mbuf **mbuf)
/* One segment must be reserved for configuration descriptor. */
if (num_frags < adapter->max_tx_sgl_size)
return (0);
+
+ if ((num_frags == adapter->max_tx_sgl_size) &&
+ ((*mbuf)->m_pkthdr.len < tx_ring->tx_max_header_size))
+ return (0);
+
counter_u64_add(tx_ring->tx_stats.collapse, 1);
collapsed_mbuf = m_collapse(*mbuf, M_NOWAIT,
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