Date: Wed, 5 May 2010 22:52:06 +0000 (UTC) From: Navdeep Parhar <np@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r207688 - head/sys/dev/cxgb Message-ID: <201005052252.o45Mq61F087929@svn.freebsd.org>
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Author: np Date: Wed May 5 22:52:06 2010 New Revision: 207688 URL: http://svn.freebsd.org/changeset/base/207688 Log: Don't ring the tx doorbell for every frame when we know more frames will follow. Adjust the freelist and response queue doorbells too. Discussed with: kmacy Modified: head/sys/dev/cxgb/cxgb_adapter.h head/sys/dev/cxgb/cxgb_sge.c Modified: head/sys/dev/cxgb/cxgb_adapter.h ============================================================================== --- head/sys/dev/cxgb/cxgb_adapter.h Wed May 5 22:29:54 2010 (r207687) +++ head/sys/dev/cxgb/cxgb_adapter.h Wed May 5 22:52:06 2010 (r207688) @@ -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; Modified: head/sys/dev/cxgb/cxgb_sge.c ============================================================================== --- head/sys/dev/cxgb/cxgb_sge.c Wed May 5 22:29:54 2010 (r207687) +++ head/sys/dev/cxgb/cxgb_sge.c Wed May 5 22:52:06 2010 (r207688) @@ -696,7 +696,7 @@ refill_fl(adapter_t *sc, struct sge_fl * 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 * 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_ 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_seg * 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 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 mbu 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 mbu 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 mbu 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 mbu 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, (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_ 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, struc r = rspq->desc; } - if (++rspq->credits >= (rspq->size / 4)) { + if (++rspq->credits >= 64) { refill_rspq(adap, rspq, rspq->credits); rspq->credits = 0; }
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