On Tue, Apr 19, 2011 at 8:19 PM, Freddie Cash <fjwc...@gmail.com> wrote:
> On Tue, Apr 19, 2011 at 7:42 AM, K. Macy <km...@freebsd.org> wrote:
>>> I'm not able to find IFNET_MULTIQUEUE in a recent 8.2-STABLE, is this
>>> something
>>> present only in HEAD?
>>
>> It looks like it is now EM_MULTIQUEUE.
>
> Just curious, how would one enable this to test it? We have igb(4)
> interfaces in our new storage boxes, and it would be interesting to
> test whether or not it helps in our setup.
>
It should automatically allocate a queue per core up to the max
supported. Post 8.0 it should be enabled by default for igb:
#if __FreeBSD_version >= 800000
/*
** Multiqueue Transmit driver
**
*/
static int
igb_mq_start(struct ifnet *ifp, struct mbuf *m)
{
struct adapter *adapter = ifp->if_softc;
struct igb_queue *que;
struct tx_ring *txr;
int i = 0, err = 0;
/* Which queue to use */
if ((m->m_flags & M_FLOWID) != 0)
i = m->m_pkthdr.flowid % adapter->num_queues;
txr = &adapter->tx_rings[i];
que = &adapter->queues[i];
if (IGB_TX_TRYLOCK(txr)) {
err = igb_mq_start_locked(ifp, txr, m);
IGB_TX_UNLOCK(txr);
} else {
err = drbr_enqueue(ifp, txr->br, m);
taskqueue_enqueue(que->tq, &que->que_task);
}
return (err);
}
static int
igb_mq_start_locked(struct ifnet *ifp, struct tx_ring *txr, struct mbuf *m)
{
struct adapter *adapter = txr->adapter;
struct mbuf *next;
int err = 0, enq;
IGB_TX_LOCK_ASSERT(txr);
if ((ifp->if_drv_flags & (IFF_DRV_RUNNING | IFF_DRV_OACTIVE)) !=
IFF_DRV_RUNNING || adapter->link_active == 0) {
if (m != NULL)
err = drbr_enqueue(ifp, txr->br, m);
return (err);
}
/* Call cleanup if number of TX descriptors low */
if (txr->tx_avail <= IGB_TX_CLEANUP_THRESHOLD)
igb_txeof(txr);
enq = 0;
if (m == NULL) {
next = drbr_dequeue(ifp, txr->br);
} else if (drbr_needs_enqueue(ifp, txr->br)) {
if ((err = drbr_enqueue(ifp, txr->br, m)) != 0)
return (err);
next = drbr_dequeue(ifp, txr->br);
} else
next = m;
/* Process the queue */
while (next != NULL) {
if ((err = igb_xmit(txr, &next)) != 0) {
if (next != NULL)
err = drbr_enqueue(ifp, txr->br, next);
break;
}
enq++;
drbr_stats_update(ifp, next->m_pkthdr.len, next->m_flags);
ETHER_BPF_MTAP(ifp, next);
if ((ifp->if_drv_flags & IFF_DRV_RUNNING) == 0)
break;
if (txr->tx_avail <= IGB_TX_OP_THRESHOLD) {
ifp->if_drv_flags |= IFF_DRV_OACTIVE;
break;
}
next = drbr_dequeue(ifp, txr->br);
}
if (enq > 0) {
/* Set the watchdog */
txr->queue_status = IGB_QUEUE_WORKING;
txr->watchdog_time = ticks;
}
return (err);
}
I haven't tested this to make sure there aren't any hidden locking
performance issues.
Cheers
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