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Don't ring the tx doorbell for every frame when we know more frames

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will follow.  Adjust the freelist and response queue doorbells too.

Discussed with:	kmacy
This commit is contained in:
np 2010-05-05 22:52:06 +00:00
parent eaf3456250
commit c7a40a3bf1
2 changed files with 32 additions and 18 deletions
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2
sys/dev/cxgb/cxgb_adapter.h
View File

@ -204,6 +204,7 @@ struct sge_fl {
uint32_t cidx;
uint32_t pidx;
uint32_t gen;
uint32_t db_pending;
bus_addr_t phys_addr;
uint32_t cntxt_id;
uint32_t empty;
@ -232,6 +233,7 @@ struct sge_txq {
uint32_t pidx;
uint32_t gen;
uint32_t unacked;
uint32_t db_pending;
struct tx_desc *desc;
struct tx_sw_desc *sdesc;
uint32_t token;

48
sys/dev/cxgb/cxgb_sge.c
View File

@ -696,7 +696,7 @@ refill_fl(adapter_t *sc, struct sge_fl *q, int n)
struct refill_fl_cb_arg cb_arg;
struct mbuf *m;
caddr_t cl;
int err, count = 0;
int err;
cb_arg.error = 0;
while (n--) {
@ -754,12 +754,14 @@ refill_fl(adapter_t *sc, struct sge_fl *q, int n)
d = q->desc;
}
q->credits++;
count++;
q->db_pending++;
}
done:
if (count)
if (q->db_pending >= 32) {
q->db_pending = 0;
t3_write_reg(sc, A_SG_KDOORBELL, V_EGRCNTX(q->cntxt_id));
}
}
@ -810,8 +812,10 @@ __refill_fl(adapter_t *adap, struct sge_fl *fl)
static __inline void
__refill_fl_lt(adapter_t *adap, struct sge_fl *fl, int max)
{
if ((fl->size - fl->credits) < max)
refill_fl(adap, fl, min(max, fl->size - fl->credits));
uint32_t reclaimable = fl->size - fl->credits;
if (reclaimable > 0)
refill_fl(adap, fl, min(max, reclaimable));
}
/**
@ -1261,7 +1265,7 @@ make_sgl(struct sg_ent *sgp, bus_dma_segment_t *segs, int nsegs)
* When GTS is disabled we unconditionally ring the doorbell.
*/
static __inline void
check_ring_tx_db(adapter_t *adap, struct sge_txq *q)
check_ring_tx_db(adapter_t *adap, struct sge_txq *q, int mustring)
{
#if USE_GTS
clear_bit(TXQ_LAST_PKT_DB, &q->flags);
@ -1275,9 +1279,12 @@ check_ring_tx_db(adapter_t *adap, struct sge_txq *q)
F_SELEGRCNTX | V_EGRCNTX(q->cntxt_id));
}
#else
wmb(); /* write descriptors before telling HW */
t3_write_reg(adap, A_SG_KDOORBELL,
F_SELEGRCNTX | V_EGRCNTX(q->cntxt_id));
if (mustring || ++q->db_pending >= 32) {
wmb(); /* write descriptors before telling HW */
t3_write_reg(adap, A_SG_KDOORBELL,
F_SELEGRCNTX | V_EGRCNTX(q->cntxt_id));
q->db_pending = 0;
}
#endif
}
@ -1480,7 +1487,7 @@ t3_encap(struct sge_qset *qs, struct mbuf **m)
wmb();
ETHER_BPF_MTAP(pi->ifp, m0);
wr_gen2(txd, txqs.gen);
check_ring_tx_db(sc, txq);
check_ring_tx_db(sc, txq, 0);
return (0);
} else if (tso_info) {
int eth_type;
@ -1543,7 +1550,7 @@ t3_encap(struct sge_qset *qs, struct mbuf **m)
wmb();
ETHER_BPF_MTAP(pi->ifp, m0);
wr_gen2(txd, txqs.gen);
check_ring_tx_db(sc, txq);
check_ring_tx_db(sc, txq, 0);
m_freem(m0);
return (0);
}
@ -1574,7 +1581,7 @@ t3_encap(struct sge_qset *qs, struct mbuf **m)
wmb();
ETHER_BPF_MTAP(pi->ifp, m0);
wr_gen2(txd, txqs.gen);
check_ring_tx_db(sc, txq);
check_ring_tx_db(sc, txq, 0);
m_freem(m0);
return (0);
}
@ -1593,7 +1600,7 @@ t3_encap(struct sge_qset *qs, struct mbuf **m)
wr_lo = htonl(V_WR_TID(txq->token));
write_wr_hdr_sgl(ndesc, txd, &txqs, txq, sgl, flits,
sgl_flits, wr_hi, wr_lo);
check_ring_tx_db(sc, txq);
check_ring_tx_db(sc, txq, 0);
return (0);
}
@ -1643,7 +1650,6 @@ cxgb_start_locked(struct sge_qset *qs)
{
struct mbuf *m_head = NULL;
struct sge_txq *txq = &qs->txq[TXQ_ETH];
int in_use_init = txq->in_use;
struct port_info *pi = qs->port;
struct ifnet *ifp = pi->ifp;
@ -1655,8 +1661,7 @@ cxgb_start_locked(struct sge_qset *qs)
return;
}
TXQ_LOCK_ASSERT(qs);
while ((txq->in_use - in_use_init < TX_START_MAX_DESC) &&
!TXQ_RING_EMPTY(qs) && (ifp->if_drv_flags & IFF_DRV_RUNNING) &&
while (!TXQ_RING_EMPTY(qs) && (ifp->if_drv_flags & IFF_DRV_RUNNING) &&
pi->link_config.link_ok) {
reclaim_completed_tx(qs, cxgb_tx_reclaim_threshold, TXQ_ETH);
@ -1674,6 +1679,10 @@ cxgb_start_locked(struct sge_qset *qs)
m_head = NULL;
}
if (txq->db_pending)
check_ring_tx_db(pi->adapter, txq, 1);
if (!TXQ_RING_EMPTY(qs) && callout_pending(&txq->txq_timer) == 0 &&
pi->link_config.link_ok)
callout_reset_on(&txq->txq_timer, 1, cxgb_tx_timeout,
@ -1707,6 +1716,9 @@ cxgb_transmit_locked(struct ifnet *ifp, struct sge_qset *qs, struct mbuf *m)
(error = drbr_enqueue(ifp, br, m)) != 0)
return (error);
} else {
if (txq->db_pending)
check_ring_tx_db(pi->adapter, txq, 1);
/*
* We've bypassed the buf ring so we need to update
* the stats directly
@ -2354,7 +2366,7 @@ again: reclaim_completed_tx(qs, 16, TXQ_OFLD);
TXQ_UNLOCK(qs);
write_ofld_wr(adap, m, q, pidx, gen, ndesc, segs, nsegs);
check_ring_tx_db(adap, q);
check_ring_tx_db(adap, q, 1);
return (0);
}
@ -3033,7 +3045,7 @@ process_responses(adapter_t *adap, struct sge_qset *qs, int budget)
r = rspq->desc;
}
if (++rspq->credits >= (rspq->size / 4)) {
if (++rspq->credits >= 64) {
refill_rspq(adap, rspq, rspq->credits);
rspq->credits = 0;
}