Multi-queue NIC drivers and multi-port lagg tend to use the same lower

bits of the flowid as each other, resulting in a poor distribution of
packets among queues in certain cases.  Work around this by adding a
set of sysctls for controlling a bit-shift on the flowid when doing
multi-port aggrigation in lagg and lacp.  By default, lagg/lacp will
now use bits 16 and higher instead of 0 and higher.

Reviewed by:	max
Obtained from:	Netflix
MFC after:	3 days

1 files changed, 1 insertions, 0 deletions

diff --git a/sys/net/if_lagg.h b/sys/net/if_lagg.h
index 0db8da8..e52f901 100644
--- a/sys/net/if_lagg.h
+++ b/sys/net/if_lagg.h
@@ -231,6 +231,7 @@ struct lagg_softc {
 	struct sysctl_ctx_list		ctx;		/* sysctl variables */
 	struct sysctl_oid		*sc_oid;	/* sysctl tree oid */
 	int				use_flowid;	/* use M_FLOWID */
+	int				flowid_shift;	/* shift the flowid */
 };
 
 struct lagg_port {