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Date:      Wed, 22 Feb 2012 22:01:30 +0000 (UTC)
From:      Andrew Thompson <thompsa@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r232008 - head/sys/net
Message-ID:  <201202222201.q1MM1Ubv070934@svn.freebsd.org>
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Author: thompsa
Date: Wed Feb 22 22:01:30 2012
New Revision: 232008
URL: http://svn.freebsd.org/changeset/base/232008

Log:
  Using the flowid in the mbuf assumes the network card is giving a good hash for
  the traffic flow, this may not be the case giving poor traffic distribution.
  Add a sysctl which allows us to fall back to our own flow hash code.
  
  PR:		kern/164901
  Submitted by:	Eugene Grosbein
  MFC after:	1 week

Modified:
  head/sys/net/ieee8023ad_lacp.c
  head/sys/net/if_lagg.c
  head/sys/net/if_lagg.h

Modified: head/sys/net/ieee8023ad_lacp.c
==============================================================================
--- head/sys/net/ieee8023ad_lacp.c	Wed Feb 22 21:47:50 2012	(r232007)
+++ head/sys/net/ieee8023ad_lacp.c	Wed Feb 22 22:01:30 2012	(r232008)
@@ -812,7 +812,7 @@ lacp_select_tx_port(struct lagg_softc *s
 		return (NULL);
 	}
 
-	if (m->m_flags & M_FLOWID)
+	if (sc->use_flowid && (m->m_flags & M_FLOWID))
 		hash = m->m_pkthdr.flowid;
 	else
 		hash = lagg_hashmbuf(m, lsc->lsc_hashkey);

Modified: head/sys/net/if_lagg.c
==============================================================================
--- head/sys/net/if_lagg.c	Wed Feb 22 21:47:50 2012	(r232007)
+++ head/sys/net/if_lagg.c	Wed Feb 22 22:01:30 2012	(r232008)
@@ -262,6 +262,8 @@ lagg_clone_create(struct if_clone *ifc, 
 	struct ifnet *ifp;
 	int i, error = 0;
 	static const u_char eaddr[6];	/* 00:00:00:00:00:00 */
+	struct sysctl_oid *oid;
+	char num[14];			/* sufficient for 32 bits */
 
 	sc = malloc(sizeof(*sc), M_DEVBUF, M_WAITOK|M_ZERO);
 	ifp = sc->sc_ifp = if_alloc(IFT_ETHER);
@@ -270,6 +272,15 @@ lagg_clone_create(struct if_clone *ifc, 
 		return (ENOSPC);
 	}
 
+	sysctl_ctx_init(&sc->ctx);
+	snprintf(num, sizeof(num), "%u", unit);
+	sc->use_flowid = 1;
+	oid = SYSCTL_ADD_NODE(&sc->ctx, &SYSCTL_NODE_CHILDREN(_net_link, lagg),
+		OID_AUTO, num, CTLFLAG_RD, NULL, "");
+	SYSCTL_ADD_INT(&sc->ctx, SYSCTL_CHILDREN(oid), OID_AUTO,
+		"use_flowid", CTLTYPE_INT|CTLFLAG_RW, &sc->use_flowid, sc->use_flowid,
+		"Use flow id for load sharing");
+
 	sc->sc_proto = LAGG_PROTO_NONE;
 	for (i = 0; lagg_protos[i].ti_proto != LAGG_PROTO_NONE; i++) {
 		if (lagg_protos[i].ti_proto == LAGG_PROTO_DEFAULT) {
@@ -349,6 +360,7 @@ lagg_clone_destroy(struct ifnet *ifp)
 
 	LAGG_WUNLOCK(sc);
 
+	sysctl_ctx_free(&sc->ctx);
 	ifmedia_removeall(&sc->sc_media);
 	ether_ifdetach(ifp);
 	if_free(ifp);
@@ -1676,7 +1688,7 @@ lagg_lb_start(struct lagg_softc *sc, str
 	struct lagg_port *lp = NULL;
 	uint32_t p = 0;
 
-	if (m->m_flags & M_FLOWID)
+	if (sc->use_flowid && (m->m_flags & M_FLOWID))
 		p = m->m_pkthdr.flowid;
 	else
 		p = lagg_hashmbuf(m, lb->lb_key);

Modified: head/sys/net/if_lagg.h
==============================================================================
--- head/sys/net/if_lagg.h	Wed Feb 22 21:47:50 2012	(r232007)
+++ head/sys/net/if_lagg.h	Wed Feb 22 22:01:30 2012	(r232008)
@@ -21,6 +21,8 @@
 #ifndef _NET_LAGG_H
 #define _NET_LAGG_H
 
+#include <sys/sysctl.h>
+
 /*
  * Global definitions
  */
@@ -202,6 +204,8 @@ struct lagg_softc {
 	eventhandler_tag vlan_attach;
 	eventhandler_tag vlan_detach;
 #endif
+	struct sysctl_ctx_list		ctx;		/* sysctl variables */
+	int				use_flowid;	/* use M_FLOWID */
 };
 
 struct lagg_port {

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