Make some small performance tweaks to the tl driver. This should hopefully

close PR #13757, however I'm waiting on user feedback before declaring the
PR officially closed. Among other things, this improves UDP transmit
performance, and tx underruns are now detected and the TX start threshold
adjusted accordingly.

1 files changed, 30 insertions, 39 deletions

diff --git a/sys/pci/if_tl.c b/sys/pci/if_tl.c
index b642e93..ed43a81 100644
--- a/sys/pci/if_tl.c
+++ b/sys/pci/if_tl.c
@@ -1058,9 +1058,6 @@ static void tl_softreset(sc, internal)
 	if (sc->tl_bitrate)
 		tl_dio_setbit16(sc, TL_NETCONFIG, TL_CFG_BITRATE);
 
-        /* Set PCI burst size */
-	tl_dio_write8(sc, TL_BSIZEREG, 0x33);
-
 	/*
 	 * Load adapter irq pacing timer and tx threshold.
 	 * We make the transmit threshold 1 initially but we may
@@ -1116,8 +1113,6 @@ static int tl_attach(dev)
 	struct tl_type		*t;
 	struct ifnet		*ifp;
 	struct tl_softc		*sc;
-	unsigned int		round;
-	caddr_t			roundptr;
 	int			unit, error = 0, rid;
 
 	s = splimp();
@@ -1229,21 +1224,12 @@ static int tl_attach(dev)
 	}
 
 	/*
-	 * Now allocate memory for the TX and RX lists. Note that
-	 * we actually allocate 8 bytes more than we really need:
-	 * this is because we need to adjust the final address to
-	 * be aligned on a quadword (64-bit) boundary in order to
-	 * make the chip happy. If the list structures aren't properly
-	 * aligned, DMA fails and the chip generates an adapter check
-	 * interrupt and has to be reset. If you set up the softc struct
-	 * just right you can sort of obtain proper alignment 'by chance.'
-	 * But I don't want to depend on this, so instead the alignment
-	 * is forced here.
+	 * Now allocate memory for the TX and RX lists.
 	 */
-	sc->tl_ldata_ptr = malloc(sizeof(struct tl_list_data) + 8,
-				M_DEVBUF, M_NOWAIT);
+	sc->tl_ldata = contigmalloc(sizeof(struct tl_list_data), M_DEVBUF,
+	    M_NOWAIT, 0x100000, 0xffffffff, PAGE_SIZE, 0);
 
-	if (sc->tl_ldata_ptr == NULL) {
+	if (sc->tl_ldata == NULL) {
 		bus_teardown_intr(dev, sc->tl_irq, sc->tl_intrhand);
 		bus_release_resource(dev, SYS_RES_IRQ, 0, sc->tl_irq);
 		bus_release_resource(dev, TL_RES, TL_RID, sc->tl_res);
@@ -1252,23 +1238,6 @@ static int tl_attach(dev)
 		goto fail;
 	}
 
-	/*
-	 * Convoluted but satisfies my ANSI sensibilities. GCC lets
-	 * you do casts on the LHS of an assignment, but ANSI doesn't
-	 * allow that.
-	 */
-	sc->tl_ldata = (struct tl_list_data *)sc->tl_ldata_ptr;
-	round = (uintptr_t)sc->tl_ldata_ptr & 0xF;
-	roundptr = sc->tl_ldata_ptr;
-	for (i = 0; i < 8; i++) {
-		if (round % 8) {
-			round++;
-			roundptr++;
-		} else
-			break;
-	}
-	sc->tl_ldata = (struct tl_list_data *)roundptr;
-
 	bzero(sc->tl_ldata, sizeof(struct tl_list_data));
 
 	sc->tl_unit = unit;
@@ -1291,7 +1260,8 @@ static int tl_attach(dev)
 		bus_teardown_intr(dev, sc->tl_irq, sc->tl_intrhand);
 		bus_release_resource(dev, SYS_RES_IRQ, 0, sc->tl_irq);
 		bus_release_resource(dev, TL_RES, TL_RID, sc->tl_res);
-		free(sc->tl_ldata_ptr, M_DEVBUF);
+		contigfree(sc->tl_ldata,
+		    sizeof(struct tl_list_data), M_DEVBUF);
 		printf("tl%d: failed to read station address\n", unit);
 		error = ENXIO;
 		goto fail;
@@ -1336,7 +1306,7 @@ static int tl_attach(dev)
 	ifp->if_watchdog = tl_watchdog;
 	ifp->if_init = tl_init;
 	ifp->if_mtu = ETHERMTU;
-	ifp->if_snd.ifq_maxlen = IFQ_MAXLEN;
+	ifp->if_snd.ifq_maxlen = TL_TX_LIST_CNT - 1;
 	callout_handle_init(&sc->tl_stat_ch);
 
 	/* Reset the adapter again. */
@@ -1399,7 +1369,7 @@ static int tl_detach(dev)
 	bus_generic_detach(dev);
 	device_delete_child(dev, sc->tl_miibus);
 
-	free(sc->tl_ldata_ptr, M_DEVBUF);
+	contigfree(sc->tl_ldata, sizeof(struct tl_list_data), M_DEVBUF);
 	if (sc->tl_bitrate)
 		ifmedia_removeall(&sc->ifmedia);
 
@@ -1713,7 +1683,7 @@ static int tl_intvec_txeoc(xsc, type)
 		CMD_PUT(sc, TL_CMD_ACK | 0x00000001 | type);
 		/* Then load the address of the next TX list. */
 		CSR_WRITE_4(sc, TL_CH_PARM,
-				vtophys(sc->tl_cdata.tl_tx_head->tl_ptr));
+		    vtophys(sc->tl_cdata.tl_tx_head->tl_ptr));
 		/* Restart TX channel. */
 		cmd = CSR_READ_4(sc, TL_HOSTCMD);
 		cmd &= ~TL_CMD_RT;
@@ -1868,6 +1838,20 @@ static void tl_stats_update(xsc)
 			    tl_rx_overrun(tl_stats);
 	ifp->if_oerrors += tl_tx_underrun(tl_stats);
 
+	if (tl_tx_underrun(tl_stats)) {
+		u_int8_t		tx_thresh;
+		tx_thresh = tl_dio_read8(sc, TL_ACOMMIT) & TL_AC_TXTHRESH;
+		if (tx_thresh != TL_AC_TXTHRESH_WHOLEPKT) {
+			tx_thresh >>= 4;
+			tx_thresh++;
+			printf("tl%d: tx underrun -- increasing "
+			    "tx threshold to %d bytes\n", sc->tl_unit,
+			    (64 * (tx_thresh * 4)));
+			tl_dio_clrbit(sc, TL_ACOMMIT, TL_AC_TXTHRESH);
+			tl_dio_setbit(sc, TL_ACOMMIT, tx_thresh << 4);
+		}
+	}
+
 	sc->tl_stat_ch = timeout(tl_stats_update, sc, hz);
 
 	if (!sc->tl_bitrate) {
@@ -2088,6 +2072,13 @@ static void tl_init(xsc)
 	 */
 	tl_stop(sc);
 
+	/* Initialize TX FIFO threshold */
+	tl_dio_clrbit(sc, TL_ACOMMIT, TL_AC_TXTHRESH);
+	tl_dio_setbit(sc, TL_ACOMMIT, TL_AC_TXTHRESH_16LONG);
+
+        /* Set PCI burst size */
+	tl_dio_write8(sc, TL_BSIZEREG, TL_RXBURST_16LONG|TL_TXBURST_16LONG);
+
 	/*
 	 * Set 'capture all frames' bit for promiscuous mode.
 	 */