Author: np
Date: Fri Mar 6 20:39:19 2015
New Revision: 279700
URL: https://svnweb.freebsd.org/changeset/base/279700
Log:
cxgbe(4): knobs to experiment with the interrupt coalescing timer for
netmap rx queues, and the "batchiness" of rx updates sent to the chip.
These knobs will probably become per-rxq in the near future and will be
documented only after their final form is decided.
MFC after: 1 month
Modified:
head/sys/dev/cxgbe/t4_netmap.c
Modified: head/sys/dev/cxgbe/t4_netmap.c
==============================================================================
--- head/sys/dev/cxgbe/t4_netmap.c Fri Mar 6 20:34:28 2015
(r279699)
+++ head/sys/dev/cxgbe/t4_netmap.c Fri Mar 6 20:39:19 2015
(r279700)
@@ -58,6 +58,16 @@ extern int fl_pad; /* XXXNM */
extern int spg_len; /* XXXNM */
extern int fl_pktshift; /* XXXNM */
+SYSCTL_NODE(_hw, OID_AUTO, cxgbe, CTLFLAG_RD, 0, "cxgbe netmap parameters");
+
+int rx_ndesc = 256;
+SYSCTL_INT(_hw_cxgbe, OID_AUTO, nm_rx_ndesc, CTLFLAG_RWTUN,
+ &rx_ndesc, 0, "# of rx descriptors after which the hw cidx is updated.");
+
+int holdoff_tmr_idx = 2;
+SYSCTL_INT(_hw_cxgbe, OID_AUTO, nm_holdoff_tmr_idx, CTLFLAG_RWTUN,
+ &holdoff_tmr_idx, 0, "Holdoff timer index for netmap rx queues.");
+
/* netmap ifnet routines */
static void cxgbe_nm_init(void *);
static int cxgbe_nm_ioctl(struct ifnet *, unsigned long, caddr_t);
@@ -344,8 +354,8 @@ alloc_nm_rxq_hwq(struct port_info *pi, s
}
t4_write_reg(sc, MYPF_REG(A_SGE_PF_GTS),
- V_SEINTARM(V_QINTR_TIMER_IDX(1)) |
- V_INGRESSQID(nm_rxq->iq_cntxt_id));
+ V_INGRESSQID(nm_rxq->iq_cntxt_id) |
+ V_SEINTARM(V_QINTR_TIMER_IDX(holdoff_tmr_idx)));
return (rc);
}
@@ -491,13 +501,14 @@ cxgbe_netmap_on(struct adapter *sc, stru
/* We deal with 8 bufs at a time */
MPASS((na->num_rx_desc & 7) == 0);
MPASS(na->num_rx_desc == nm_rxq->fl_sidx);
- for (j = 0; j < nm_rxq->fl_sidx - 8; j++) {
+ for (j = 0; j < nm_rxq->fl_sidx; j++) {
uint64_t ba;
PNMB(na, &slot[j], &ba);
+ MPASS(ba != 0);
nm_rxq->fl_desc[j] = htobe64(ba | hwidx);
}
- nm_rxq->fl_pidx = j;
+ j = nm_rxq->fl_pidx = nm_rxq->fl_sidx - 8;
MPASS((j & 7) == 0);
j /= 8; /* driver pidx to hardware pidx */
wmb();
@@ -708,6 +719,7 @@ cxgbe_nm_tx(struct adapter *sc, struct s
for (i = 0; i < n; i++) {
slot = &ring->slot[kring->nr_hwcur];
PNMB(kring->na, slot, &ba);
+ MPASS(ba != 0);
cpl->ctrl0 = nm_txq->cpl_ctrl0;
cpl->pack = 0;
@@ -933,6 +945,7 @@ cxgbe_netmap_rxsync(struct netmap_kring
while (n > 0) {
for (i = 0; i < 8; i++, fl_pidx++, slot++) {
PNMB(na, slot, &ba);
+ MPASS(ba != 0);
nm_rxq->fl_desc[fl_pidx] = htobe64(ba | hwidx);
slot->flags &= ~NS_BUF_CHANGED;
MPASS(fl_pidx <= nm_rxq->fl_sidx);
@@ -1107,8 +1120,7 @@ t4_nm_intr(void *arg)
struct netmap_ring *ring = kring->ring;
struct iq_desc *d = &nm_rxq->iq_desc[nm_rxq->iq_cidx];
uint32_t lq;
- u_int n = 0;
- int processed = 0;
+ u_int n = 0, work = 0;
uint8_t opcode;
uint32_t fl_cidx = atomic_load_acq_32(&nm_rxq->fl_cidx);
@@ -1164,7 +1176,10 @@ t4_nm_intr(void *arg)
nm_rxq->iq_gen ^= F_RSPD_GEN;
}
- if (__predict_false(++n == 64)) { /* XXXNM: tune */
+ if (__predict_false(++n == rx_ndesc)) {
+ atomic_store_rel_32(&nm_rxq->fl_cidx, fl_cidx);
+ netmap_rx_irq(ifp, nm_rxq->nid, &work);
+ MPASS(work != 0);
t4_write_reg(sc, MYPF_REG(A_SGE_PF_GTS),
V_CIDXINC(n) | V_INGRESSQID(nm_rxq->iq_cntxt_id) |
V_SEINTARM(V_QINTR_TIMER_IDX(X_TIMERREG_UPDATE_CIDX)));
@@ -1173,10 +1188,10 @@ t4_nm_intr(void *arg)
}
if (fl_cidx != nm_rxq->fl_cidx) {
atomic_store_rel_32(&nm_rxq->fl_cidx, fl_cidx);
- netmap_rx_irq(ifp, nm_rxq->nid, &processed);
+ netmap_rx_irq(ifp, nm_rxq->nid, &work);
}
t4_write_reg(sc, MYPF_REG(A_SGE_PF_GTS), V_CIDXINC(n) |
V_INGRESSQID((u32)nm_rxq->iq_cntxt_id) |
- V_SEINTARM(V_QINTR_TIMER_IDX(1)));
+ V_SEINTARM(V_QINTR_TIMER_IDX(holdoff_tmr_idx)));
}
#endif
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