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Implement rudimentary interrupt moderation with programmable

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countdown timer register. The timer resolution may vary among
controllers but the value would be represented by core clock
cycles. msk(4) will automatically computes number of required clock
cycles from given micro-seconds unit.
The default interrupt holdoff timer value is 100us which will
ensure less than 10k interrupts under load. The timer value can be
changed with dev.mskc.0.int_holdoff sysctl node.

Note, the interrupt moderation is shared resource on dual-port
controllers so you can't use separate interrupt moderation value
for each port. This means we can't stop interrupt moderation in
driver stop routine. Also have msk_tick() reclaim transmitted Tx
buffers as safety belt. With this change there is no need to check
missing Tx completion interrupt in watchdog handler, so remove it.
This commit is contained in:
yongari 2010-03-01 23:39:43 +00:00
parent a6965976ff
commit 2f0c753d6e
2 changed files with 23 additions and 20 deletions
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40
sys/dev/msk/if_msk.c
View File

@ -1659,6 +1659,14 @@ mskc_attach(device_t dev)
}
}
sc->msk_int_holdoff = MSK_INT_HOLDOFF_DEFAULT;
SYSCTL_ADD_INT(device_get_sysctl_ctx(dev),
SYSCTL_CHILDREN(device_get_sysctl_tree(dev)), OID_AUTO,
"int_holdoff", CTLFLAG_RW, &sc->msk_int_holdoff, 0,
"Maximum number of time to delay interrupts");
resource_int_value(device_get_name(dev), device_get_unit(dev),
"int_holdoff", &sc->msk_int_holdoff);
/* Soft reset. */
CSR_WRITE_2(sc, B0_CTST, CS_RST_SET);
CSR_WRITE_2(sc, B0_CTST, CS_RST_CLR);
@ -2801,8 +2809,6 @@ static void
msk_watchdog(struct msk_if_softc *sc_if)
{
struct ifnet *ifp;
uint32_t ridx;
int idx;
MSK_IF_LOCK_ASSERT(sc_if);
@ -2819,24 +2825,6 @@ msk_watchdog(struct msk_if_softc *sc_if)
return;
}
/*
* Reclaim first as there is a possibility of losing Tx completion
* interrupts.
*/
ridx = sc_if->msk_port == MSK_PORT_A ? STAT_TXA1_RIDX : STAT_TXA2_RIDX;
idx = CSR_READ_2(sc_if->msk_softc, ridx);
if (sc_if->msk_cdata.msk_tx_cons != idx) {
msk_txeof(sc_if, idx);
if (sc_if->msk_cdata.msk_tx_cnt == 0) {
if_printf(ifp, "watchdog timeout (missed Tx interrupts) "
"-- recovering\n");
if (!IFQ_DRV_IS_EMPTY(&ifp->if_snd))
taskqueue_enqueue(taskqueue_fast,
&sc_if->msk_tx_task);
return;
}
}
if_printf(ifp, "watchdog timeout\n");
ifp->if_oerrors++;
ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
@ -3166,6 +3154,7 @@ msk_tick(void *xsc_if)
mii_tick(mii);
if ((sc_if->msk_flags & MSK_FLAG_LINK) == 0)
msk_miibus_statchg(sc_if->msk_if_dev);
msk_handle_events(sc_if->msk_softc);
msk_watchdog(sc_if);
callout_reset(&sc_if->msk_tick_ch, hz, msk_tick, sc_if);
}
@ -3904,6 +3893,17 @@ msk_init_locked(struct msk_if_softc *sc_if)
sc->msk_intrmask |= Y2_IS_PORT_B;
sc->msk_intrhwemask |= Y2_HWE_L2_MASK;
}
/* Configure IRQ moderation mask. */
CSR_WRITE_4(sc, B2_IRQM_MSK, sc->msk_intrmask);
if (sc->msk_int_holdoff > 0) {
/* Configure initial IRQ moderation timer value. */
CSR_WRITE_4(sc, B2_IRQM_INI,
MSK_USECS(sc, sc->msk_int_holdoff));
CSR_WRITE_4(sc, B2_IRQM_VAL,
MSK_USECS(sc, sc->msk_int_holdoff));
/* Start IRQ moderation. */
CSR_WRITE_1(sc, B2_IRQM_CTRL, TIM_START);
}
CSR_WRITE_4(sc, B0_HWE_IMSK, sc->msk_intrhwemask);
CSR_READ_4(sc, B0_HWE_IMSK);
CSR_WRITE_4(sc, B0_IMSK, sc->msk_intrmask);

3
sys/dev/msk/if_mskreg.h
View File

@ -2406,6 +2406,8 @@ struct msk_ring_data {
#define MSK_PROC_MIN 30
#define MSK_PROC_MAX (MSK_RX_RING_CNT - 1)
#define MSK_INT_HOLDOFF_DEFAULT 100
#define MSK_TX_TIMEOUT 5
#define MSK_PUT_WM 10
@ -2496,6 +2498,7 @@ struct msk_softc {
bus_dmamap_t msk_stat_map;
struct msk_stat_desc *msk_stat_ring;
bus_addr_t msk_stat_ring_paddr;
int msk_int_holdoff;
int msk_process_limit;
int msk_stat_cons;
struct taskqueue *msk_tq;