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Diffstat (limited to 'share/man/man4/iflib.4')
| -rw-r--r-- | share/man/man4/iflib.4 | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/share/man/man4/iflib.4 b/share/man/man4/iflib.4 index 0114263e6ca2..2040698f0087 100644 --- a/share/man/man4/iflib.4 +++ b/share/man/man4/iflib.4 @@ -1,4 +1,4 @@ -.Dd September 27, 2018 +.Dd August 20, 2025 .Dt IFLIB 4 .Os .Sh NAME @@ -64,6 +64,18 @@ If this is zero or not set, an RX and TX queue pair will be assigned to each core. When set to a non-zero value, TX queues are assigned to cores following the last RX queue. +.It Va simple_tx +When set to one, iflib uses a simple transmit routine with no queuing at all. +By default, iflib uses a highly optimized, lockless, transmit queue called +mp_ring. +This performs well when there are more CPU cores than NIC +queues and prevents lock contention for transmit resources. +Unfortunately, mp_ring incurs unneeded overheads on workloads where +resource contention is not a problem (well behaved applications on +systems where there are as many NIC queues as CPU cores). +Note that when this is enabled, the tx_abdicate sysctl is no longer +applicable and is ignored. +Defaults to zero. .El .Pp These |