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diff --git a/share/man/man4/iflib.4 b/share/man/man4/iflib.4
--- a/share/man/man4/iflib.4
+++ b/share/man/man4/iflib.4
@@ -1,4 +1,4 @@
-.Dd September 14, 2026
+.Dd September 16, 2026
.Dt IFLIB 4
.Os
.Sh NAME
@@ -79,7 +79,9 @@
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Note that when this is enabled, the tx_abdicate sysctl is no longer
applicable and is ignored.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.
+By default, this is the inverse of
+.Va net.iflib.prefer_mpring .
+An explicitly configured value takes precedence over that global default.
.El
.Pp
These
@@ -144,6 +146,17 @@
Doing so usually increases the transmit throughput by reducing the number of
transmit interrupts.
Setting this to a non-zero value will disable the use of this feature.
+.It Va net.iflib.prefer_mpring
+When set, use the
+.Va mp_ring
+transmit path by default instead of the simple transmit path.
+This is a read-only tunable that must be set before
+.Nm
+is loaded.
+An explicitly configured per-device
+.Va simple_tx
+value takes precedence.
+The default is zero.
.It Va net.iflib.simple_drain_quota
Sets the maximum number of packets that the transmit task may remove from a
simple transmit deferral ring in one drain operation.
diff --git a/sys/net/iflib.c b/sys/net/iflib.c
--- a/sys/net/iflib.c
+++ b/sys/net/iflib.c
@@ -704,6 +704,10 @@
SYSCTL_INT(_net_iflib, OID_AUTO, simple_txbr_size, CTLFLAG_RDTUN,
&iflib_simple_txbr_size, 0,
"number of entries in the simple tx deferral ring");
+static bool iflib_prefer_mpring;
+SYSCTL_BOOL(_net_iflib, OID_AUTO, prefer_mpring, CTLFLAG_RDTUN,
+ &iflib_prefer_mpring, 0,
+ "prefer the mp_ring transmit path by default");
static u_int iflib_simple_drain_quota = 8;
SYSCTL_UINT(_net_iflib, OID_AUTO, simple_drain_quota, CTLFLAG_RWTUN,
&iflib_simple_drain_quota, 0,
@@ -7641,6 +7645,7 @@
"tx_watchdog_events", CTLFLAG_RD, &ctx->ifc_tx_watchdog_events, 0,
"TX watchdog resets initiated by iflib");
+ ctx->ifc_sysctl_simple_tx = !iflib_prefer_mpring;
SYSCTL_ADD_BOOL(&ctx->ifc_sysctl_ctx, oid_list, OID_AUTO, "simple_tx",
CTLFLAG_RDTUN, &ctx->ifc_sysctl_simple_tx, 0,
"use simple tx ring");

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