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Rework the tx credit mechanism between the cxgbe/tom driver

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and the card.  This helps smooth out some burstiness in the
exchange.

Approved by:	re (glebius)
This commit is contained in:
np 2013-09-09 04:38:57 +00:00
parent 279a0ac6ad
commit a9b6160aa1
3 changed files with 85 additions and 45 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

112
sys/dev/cxgbe/tom/t4_cpl_io.c
View File

@ -444,22 +444,12 @@ max_dsgl_nsegs(int tx_credits)
static inline void
write_tx_wr(void *dst, struct toepcb *toep, unsigned int immdlen,
unsigned int plen, uint8_t credits, int more_to_come)
unsigned int plen, uint8_t credits, int shove)
{
struct fw_ofld_tx_data_wr *txwr = dst;
int shove = !more_to_come;
int compl = 1;
/*
* We always request completion notifications from the firmware. The
* only exception is when we know we'll get more data to send shortly
* and that we'll have some tx credits remaining to transmit that data.
*/
if (more_to_come && toep->tx_credits - credits >= MIN_OFLD_TX_CREDITS)
compl = 0;
txwr->op_to_immdlen = htobe32(V_WR_OP(FW_OFLD_TX_DATA_WR) |
V_FW_WR_COMPL(compl) | V_FW_WR_IMMDLEN(immdlen));
V_FW_WR_IMMDLEN(immdlen));
txwr->flowid_len16 = htobe32(V_FW_WR_FLOWID(toep->tid) |
V_FW_WR_LEN16(credits));
txwr->tunnel_to_proxy =
@ -529,19 +519,26 @@ write_tx_sgl(void *dst, struct mbuf *start, struct mbuf *stop, int nsegs, int n)
* The socket's so_snd buffer consists of a stream of data starting with sb_mb
* and linked together with m_next. sb_sndptr, if set, is the last mbuf that
* was transmitted.
*
* drop indicates the number of bytes that should be dropped from the head of
* the send buffer. It is an optimization that lets do_fw4_ack avoid creating
* contention on the send buffer lock (before this change it used to do
* sowwakeup and then t4_push_frames right after that when recovering from tx
* stalls). When drop is set this function MUST drop the bytes and wake up any
* writers.
*/
static void
t4_push_frames(struct adapter *sc, struct toepcb *toep)
t4_push_frames(struct adapter *sc, struct toepcb *toep, int drop)
{
struct mbuf *sndptr, *m, *sb_sndptr;
struct fw_ofld_tx_data_wr *txwr;
struct wrqe *wr;
unsigned int plen, nsegs, credits, max_imm, max_nsegs, max_nsegs_1mbuf;
u_int plen, nsegs, credits, max_imm, max_nsegs, max_nsegs_1mbuf;
struct inpcb *inp = toep->inp;
struct tcpcb *tp = intotcpcb(inp);
struct socket *so = inp->inp_socket;
struct sockbuf *sb = &so->so_snd;
int tx_credits;
int tx_credits, shove, compl, space, sowwakeup;
struct ofld_tx_sdesc *txsd = &toep->txsd[toep->txsd_pidx];
INP_WLOCK_ASSERT(inp);
@ -557,8 +554,11 @@ t4_push_frames(struct adapter *sc, struct toepcb *toep)
* This function doesn't resume by itself. Someone else must clear the
* flag and call this function.
*/
if (__predict_false(toep->flags & TPF_TX_SUSPENDED))
if (__predict_false(toep->flags & TPF_TX_SUSPENDED)) {
KASSERT(drop == 0,
("%s: drop (%d) != 0 but tx is suspended", __func__, drop));
return;
}
do {
tx_credits = min(toep->tx_credits, MAX_OFLD_TX_CREDITS);
@ -566,6 +566,11 @@ t4_push_frames(struct adapter *sc, struct toepcb *toep)
max_nsegs = max_dsgl_nsegs(tx_credits);
SOCKBUF_LOCK(sb);
sowwakeup = drop;
if (drop) {
sbdrop_locked(sb, drop);
drop = 0;
}
sb_sndptr = sb->sb_sndptr;
sndptr = sb_sndptr ? sb_sndptr->m_next : sb->sb_mb;
plen = 0;
@ -584,7 +589,11 @@ t4_push_frames(struct adapter *sc, struct toepcb *toep)
if (plen == 0) {
/* Too few credits */
toep->flags |= TPF_TX_SUSPENDED;
SOCKBUF_UNLOCK(sb);
if (sowwakeup)
sowwakeup_locked(so);
else
SOCKBUF_UNLOCK(sb);
SOCKBUF_UNLOCK_ASSERT(sb);
return;
}
break;
@ -601,23 +610,32 @@ t4_push_frames(struct adapter *sc, struct toepcb *toep)
}
}
shove = m == NULL && !(tp->t_flags & TF_MORETOCOME);
space = sbspace(sb);
if (space <= sb->sb_hiwat * 3 / 8 &&
toep->plen_nocompl + plen >= sb->sb_hiwat / 4)
compl = 1;
else
compl = 0;
if (sb->sb_flags & SB_AUTOSIZE &&
V_tcp_do_autosndbuf &&
sb->sb_hiwat < V_tcp_autosndbuf_max &&
sbspace(sb) < sb->sb_hiwat / 8) {
space < sb->sb_hiwat / 8) {
int newsize = min(sb->sb_hiwat + V_tcp_autosndbuf_inc,
V_tcp_autosndbuf_max);
if (!sbreserve_locked(sb, newsize, so, NULL))
sb->sb_flags &= ~SB_AUTOSIZE;
else {
sowwakeup_locked(so); /* room available */
SOCKBUF_UNLOCK_ASSERT(sb);
goto unlocked;
}
else
sowwakeup = 1; /* room available */
}
SOCKBUF_UNLOCK(sb);
unlocked:
if (sowwakeup)
sowwakeup_locked(so);
else
SOCKBUF_UNLOCK(sb);
SOCKBUF_UNLOCK_ASSERT(sb);
/* nothing to send */
if (plen == 0) {
@ -642,9 +660,9 @@ unlocked:
}
txwr = wrtod(wr);
credits = howmany(wr->wr_len, 16);
write_tx_wr(txwr, toep, plen, plen, credits,
tp->t_flags & TF_MORETOCOME);
write_tx_wr(txwr, toep, plen, plen, credits, shove);
m_copydata(sndptr, 0, plen, (void *)(txwr + 1));
nsegs = 0;
} else {
int wr_len;
@ -660,8 +678,7 @@ unlocked:
}
txwr = wrtod(wr);
credits = howmany(wr_len, 16);
write_tx_wr(txwr, toep, 0, plen, credits,
tp->t_flags & TF_MORETOCOME);
write_tx_wr(txwr, toep, 0, plen, credits, shove);
write_tx_sgl(txwr + 1, sndptr, m, nsegs,
max_nsegs_1mbuf);
if (wr_len & 0xf) {
@ -675,6 +692,17 @@ unlocked:
("%s: not enough credits", __func__));
toep->tx_credits -= credits;
toep->tx_nocompl += credits;
toep->plen_nocompl += plen;
if (toep->tx_credits <= toep->tx_total * 3 / 8 &&
toep->tx_nocompl >= toep->tx_total / 4)
compl = 1;
if (compl) {
txwr->op_to_immdlen |= htobe32(F_FW_WR_COMPL);
toep->tx_nocompl = 0;
toep->plen_nocompl = 0;
}
tp->snd_nxt += plen;
tp->snd_max += plen;
@ -685,6 +713,8 @@ unlocked:
SOCKBUF_UNLOCK(sb);
toep->flags |= TPF_TX_DATA_SENT;
if (toep->tx_credits < MIN_OFLD_TX_CREDITS)
toep->flags |= TPF_TX_SUSPENDED;
KASSERT(toep->txsd_avail > 0, ("%s: no txsd", __func__));
txsd->plen = plen;
@ -718,7 +748,7 @@ t4_tod_output(struct toedev *tod, struct tcpcb *tp)
("%s: inp %p dropped.", __func__, inp));
KASSERT(toep != NULL, ("%s: toep is NULL", __func__));
t4_push_frames(sc, toep);
t4_push_frames(sc, toep, 0);
return (0);
}
@ -738,7 +768,8 @@ t4_send_fin(struct toedev *tod, struct tcpcb *tp)
KASSERT(toep != NULL, ("%s: toep is NULL", __func__));
toep->flags |= TPF_SEND_FIN;
t4_push_frames(sc, toep);
if (tp->t_state >= TCPS_ESTABLISHED)
t4_push_frames(sc, toep, 0);
return (0);
}
@ -1369,7 +1400,16 @@ do_fw4_ack(struct sge_iq *iq, const struct rss_header *rss, struct mbuf *m)
}
}
if (plen > 0) {
if (toep->tx_credits == toep->tx_total) {
toep->tx_nocompl = 0;
toep->plen_nocompl = 0;
}
if (toep->flags & TPF_TX_SUSPENDED &&
toep->tx_credits >= toep->tx_total / 4) {
toep->flags &= ~TPF_TX_SUSPENDED;
t4_push_frames(sc, toep, plen);
} else if (plen > 0) {
struct sockbuf *sb = &so->so_snd;
SOCKBUF_LOCK(sb);
@ -1378,14 +1418,6 @@ do_fw4_ack(struct sge_iq *iq, const struct rss_header *rss, struct mbuf *m)
SOCKBUF_UNLOCK_ASSERT(sb);
}
/* XXX */
if ((toep->flags & TPF_TX_SUSPENDED &&
toep->tx_credits >= MIN_OFLD_TX_CREDITS) ||
toep->tx_credits == toep->txsd_total *
howmany((sizeof(struct fw_ofld_tx_data_wr) + 1), 16)) {
toep->flags &= ~TPF_TX_SUSPENDED;
t4_push_frames(sc, toep);
}
INP_WUNLOCK(inp);
return (0);

1
sys/dev/cxgbe/tom/t4_tom.c
View File

@ -148,6 +148,7 @@ alloc_toepcb(struct port_info *pi, int txqid, int rxqid, int flags)
toep->td = sc->tom_softc;
toep->port = pi;
toep->tx_total = tx_credits;
toep->tx_credits = tx_credits;
toep->ofld_txq = &sc->sge.ofld_txq[txqid];
toep->ofld_rxq = &sc->sge.ofld_rxq[rxqid];

17
sys/dev/cxgbe/tom/t4_tom.h
View File

@ -99,7 +99,7 @@ struct ddp_buffer {
struct toepcb {
TAILQ_ENTRY(toepcb) link; /* toep_list */
unsigned int flags; /* miscellaneous flags */
u_int flags; /* miscellaneous flags */
struct tom_data *td;
struct inpcb *inp; /* backpointer to host stack's PCB */
struct port_info *port; /* physical port */
@ -109,13 +109,20 @@ struct toepcb {
struct l2t_entry *l2te; /* L2 table entry used by this connection */
struct clip_entry *ce; /* CLIP table entry used by this tid */
int tid; /* Connection identifier */
unsigned int tx_credits;/* tx WR credits (in 16 byte units) remaining */
unsigned int sb_cc; /* last noted value of so_rcv->sb_cc */
/* tx credit handling */
u_int tx_total; /* total tx WR credits (in 16B units) */
u_int tx_credits; /* tx WR credits (in 16B units) available */
u_int tx_nocompl; /* tx WR credits since last compl request */
u_int plen_nocompl; /* payload since last compl request */
/* rx credit handling */
u_int sb_cc; /* last noted value of so_rcv->sb_cc */
int rx_credits; /* rx credits (in bytes) to be returned to hw */
unsigned int ulp_mode; /* ULP mode */
u_int ulp_mode; /* ULP mode */
unsigned int ddp_flags;
u_int ddp_flags;
struct ddp_buffer *db[2];
time_t ddp_disabled;
uint8_t ddp_score;