From: claudio <claudio@openbsd.org>
Date: Thu, 9 Mar 2023 10:29:04 +0000 (+0000)
Subject: Improve vnet(4) to work better in busy conditions.
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=63d58f049f57fa2f436a2cdd6f9b36a44b048a1d;p=openbsd

Improve vnet(4) to work better in busy conditions.
No longer limit the ifq size to a low number, increase the slots on the
DMA Ring a bit and abstract the VNET buffer size into a define.
Enqueue packets on the ring but mark the initial packet ready at the end.
This way the other ldom is not able to rush ahead and overconsume packets.
The dring indexes are passed between ldoms and can get out of sync with
causes the TX ring to stall.
Tested by myself and jan@
OK kettenis@ jan@ kn@
---

diff --git a/sys/arch/sparc64/dev/vnet.c b/sys/arch/sparc64/dev/vnet.c
index a147184553c..c144bcdded3 100644
--- a/sys/arch/sparc64/dev/vnet.c
+++ b/sys/arch/sparc64/dev/vnet.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: vnet.c,v 1.66 2022/07/25 14:48:24 kn Exp $	*/
+/*	$OpenBSD: vnet.c,v 1.67 2023/03/09 10:29:04 claudio Exp $	*/
 /*
  * Copyright (c) 2009, 2015 Mark Kettenis
  *
@@ -54,8 +54,11 @@
 #define DPRINTF(x)
 #endif
 
-#define VNET_TX_ENTRIES		32
-#define VNET_RX_ENTRIES		32
+#define VNET_BUF_SIZE		2048
+
+/* 128 * 64 = 8192 which is a full page */
+#define VNET_TX_ENTRIES		128
+#define VNET_RX_ENTRIES		128
 
 struct vnet_attr_info {
 	struct vio_msg_tag	tag;
@@ -304,7 +307,8 @@ vnet_attach(struct device *parent, struct device *self, void *aux)
 	/*
 	 * Each interface gets its own pool.
 	 */
-	pool_init(&sc->sc_pool, 2048, 0, IPL_NET, 0, sc->sc_dv.dv_xname, NULL);
+	pool_init(&sc->sc_pool, VNET_BUF_SIZE, 0, IPL_NET, 0,
+	    sc->sc_dv.dv_xname, NULL);
 
 	ifp = &sc->sc_ac.ac_if;
 	ifp->if_softc = sc;
@@ -314,7 +318,6 @@ vnet_attach(struct device *parent, struct device *self, void *aux)
 	ifp->if_start = vnet_start;
 	ifp->if_watchdog = vnet_watchdog;
 	strlcpy(ifp->if_xname, sc->sc_dv.dv_xname, IFNAMSIZ);
-	ifq_set_maxlen(&ifp->if_snd, 31); /* XXX */
 
 	ifmedia_init(&sc->sc_media, 0, vnet_media_change, vnet_media_status);
 	ifmedia_add(&sc->sc_media, IFM_ETHER | IFM_AUTO, 0, NULL);
@@ -725,14 +728,14 @@ vnet_rx_vio_desc_data(struct vnet_softc *sc, struct vio_msg_tag *tag)
 
 	switch(tag->stype) {
 	case VIO_SUBTYPE_INFO:
-		buf = pool_get(&sc->sc_pool, PR_NOWAIT|PR_ZERO);
-		if (buf == NULL) {
+		nbytes = roundup(dm->nbytes, 8);
+		if (nbytes > VNET_BUF_SIZE) {
 			ifp->if_ierrors++;
 			goto skip;
 		}
-		nbytes = roundup(dm->nbytes, 8);
 
-		if (dm->nbytes > (ETHER_MAX_LEN - ETHER_CRC_LEN)) {
+		buf = pool_get(&sc->sc_pool, PR_NOWAIT|PR_ZERO);
+		if (buf == NULL) {
 			ifp->if_ierrors++;
 			goto skip;
 		}
@@ -822,7 +825,7 @@ vnet_rx_vio_dring_data(struct vnet_softc *sc, struct vio_msg_tag *tag)
 			err = hv_ldc_copy(lc->lc_id, LDC_COPY_IN, cookie,
 			    desc_pa, nbytes, &nbytes);
 			if (err != H_EOK) {
-				printf("hv_ldc_copy_in %d\n", err);
+				printf("hv_ldc_copy in %d\n", err);
 				break;
 			}
 
@@ -857,7 +860,7 @@ vnet_rx_vio_dring_data(struct vnet_softc *sc, struct vio_msg_tag *tag)
 			err = hv_ldc_copy(lc->lc_id, LDC_COPY_OUT, cookie,
 			    desc_pa, nbytes, &nbytes);
 			if (err != H_EOK)
-				printf("hv_ldc_copy_out %d\n", err);
+				printf("hv_ldc_copy out %d\n", err);
 
 			ack_end_idx = idx;
 			if (++idx == sc->sc_peer_dring_nentries)
@@ -897,12 +900,12 @@ vnet_rx_vio_dring_data(struct vnet_softc *sc, struct vio_msg_tag *tag)
 			sc->sc_tx_cons++;
 			cons = sc->sc_tx_cons & (sc->sc_vd->vd_nentries - 1);
 		}
-
+ 
+		KERNEL_LOCK();
 		count = sc->sc_tx_prod - sc->sc_tx_cons;
 		if (count > 0 && sc->sc_peer_state != VIO_DP_ACTIVE)
 			vnet_send_dring_data(sc, cons);
 
-		KERNEL_LOCK();
 		if (count < (sc->sc_vd->vd_nentries - 1))
 			ifq_clr_oactive(&ifp->if_snd);
 		if (count == 0)
@@ -1138,6 +1141,12 @@ vnet_start(struct ifnet *ifp)
 			break;
 		}
 
+		if (m->m_pkthdr.len > VNET_BUF_SIZE - VNET_ETHER_ALIGN) {
+			ifp->if_oerrors++;
+			pool_put(&sc->sc_pool, buf);
+			m_freem(m);
+			break;
+		}
 		m_copydata(m, 0, m->m_pkthdr.len, buf + VNET_ETHER_ALIGN);
 
 #if NBPFILTER > 0
@@ -1163,9 +1172,9 @@ vnet_start(struct ifnet *ifp)
 		sc->sc_vd->vd_desc[prod].ncookies = 1;
 		sc->sc_vd->vd_desc[prod].cookie[0].addr =
 		    map->lm_next << PAGE_SHIFT | (pa & PAGE_MASK);
-		sc->sc_vd->vd_desc[prod].cookie[0].size = 2048;
-		membar_producer();
-		sc->sc_vd->vd_desc[prod].hdr.dstate = VIO_DESC_READY;
+		sc->sc_vd->vd_desc[prod].cookie[0].size = VNET_BUF_SIZE;
+		if (prod != start)
+			sc->sc_vd->vd_desc[prod].hdr.dstate = VIO_DESC_READY;
 
 		sc->sc_vsd[prod].vsd_map_idx = map->lm_next;
 		sc->sc_vsd[prod].vsd_buf = buf;
@@ -1176,11 +1185,14 @@ vnet_start(struct ifnet *ifp)
 		m_freem(m);
 	}
 
-	membar_producer();
 
-	if (start != prod && sc->sc_peer_state != VIO_DP_ACTIVE) {
-		vnet_send_dring_data(sc, start);
-		ifp->if_timer = 5;
+	if (start != prod) {
+		membar_producer();
+		sc->sc_vd->vd_desc[start].hdr.dstate = VIO_DESC_READY;
+		if (sc->sc_peer_state != VIO_DP_ACTIVE) {
+			vnet_send_dring_data(sc, start);
+			ifp->if_timer = 10;
+		}
 	}
 }
 
@@ -1251,7 +1263,7 @@ vnet_start_desc(struct ifnet *ifp)
 		dm.ncookies = 1;
 		dm.cookie[0].addr =
 			map->lm_next << PAGE_SHIFT | (pa & PAGE_MASK);
-		dm.cookie[0].size = 2048;
+		dm.cookie[0].size = VNET_BUF_SIZE;
 		vnet_sendmsg(sc, &dm, sizeof(dm));
 
 		sc->sc_tx_prod++;