Date: Tue, 21 Dec 2010 13:32:16 +0600 From: Eugene Grosbein <egrosbein@rdtc.ru> To: Shtorm <admin@shtorm.com> Cc: net@freebsd.org Subject: Re: lagg/lacp poor traffic distribution Message-ID: <4D105800.2070808@rdtc.ru> In-Reply-To: <1292844095.1917.136.camel@stormi> References: <4D0CFEFF.3000902@rdtc.ru> <1292844095.1917.136.camel@stormi>
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On 20.12.2010 17:21, Shtorm wrote:
> I had this problem with igb driver, and I found, that lagg selects
> outgoing interface based on packet header flowid field if M_FLOWID field
> is set. And in the igb driver code flowid is set as
>
> #if __FreeBSD_version >= 800000
> <------><------><------>rxr->fmp->m_pkthdr.flowid = que->msix;
> <------><------><------>rxr->fmp->m_flags |= M_FLOWID;
> #endif
>
> The same thing in em driver with MULTIQUEUE
>
> That does not give enough number of flows to balance traffic well, so I
> commented check in if_lagg.c
>
> lagg_lb_start(struct lagg_softc *sc, struct mbuf *m)
> {
> <------>struct lagg_lb *lb = (struct lagg_lb *)sc->sc_psc;
> <------>struct lagg_port *lp = NULL;
> <------>uint32_t p = 0;
>
> //<---->if (m->m_flags & M_FLOWID)
> //<----><------>p = m->m_pkthdr.flowid;
> //<---->else
>
> and with this change I have much better load distribution across interfaces.
>
> Hope it helps.
>
I've made new sysctl net.link.lagg.use_flows to enable/disable
this code in run time and disabled it. No change.
--- if_lagg.c.orig 2010-12-20 22:53:21.000000000 +0600
+++ if_lagg.c 2010-12-20 22:57:50.000000000 +0600
@@ -168,6 +168,11 @@
&lagg_failover_rx_all, 0,
"Accept input from any interface in a failover lagg");
+static int lagg_use_flows = 1;
+SYSCTL_INT(_net_link_lagg, OID_AUTO, use_flows, CTLFLAG_RW,
+ &lagg_use_flows, 1,
+ "Use flows for load sharing");
+
static int
lagg_modevent(module_t mod, int type, void *data)
{
@@ -1666,7 +1671,7 @@
struct lagg_port *lp = NULL;
uint32_t p = 0;
- if (m->m_flags & M_FLOWID)
+ if (lagg_use_flows && (m->m_flags & M_FLOWID))
p = m->m_pkthdr.flowid;
else
p = lagg_hashmbuf(m, lb->lb_key);
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