[PATCH net-next] r8169: Add some tracepoints for watching rx/tx events

From: David Howells <dhowells@redhat.com>
Date: 2018-10-04 08:31:13
Also in: lkml
Subsystem: 8169 10/100/1000 gigabit ethernet driver, networking drivers, the rest, tracing · Maintainers: Heiner Kallweit, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Steven Rostedt, Masami Hiramatsu

Add some tracepoints into the Realtek r8169 driver to watch events involved
in the reception and transmission of packets, including:

 (1) Interrupts occurring.  The device status is logged.

 (2) NAPI polling.  The device status is logged.

 (3) Packet received and about to be handed off.  The sk_buff address is
     logged.

 (4) Packet queued for transmission and device poked.  The sk_buff address
     is logged along with the revised Tx ring indices.

 (5) Packet removed from Tx ring after transmission.  The sk_buff address
     is logged along with the Tx ring slot number.

Signed-off-by: David Howells <dhowells@redhat.com>
---

 drivers/net/ethernet/realtek/r8169.c |    9 ++
 include/trace/events/net_rtl8169.h   |  125 ++++++++++++++++++++++++++++++++++
 2 files changed, 134 insertions(+)
 create mode 100644 include/trace/events/net_rtl8169.h

diff --git a/drivers/net/ethernet/realtek/r8169.c b/drivers/net/ethernet/realtek/r8169.c
index 9a5e2969df61..1d4d3d953628 100644
--- a/drivers/net/ethernet/realtek/r8169.c
+++ b/drivers/net/ethernet/realtek/r8169.c

@@ -31,6 +31,9 @@
 #include <linux/ipv6.h>
 #include <net/ip6_checksum.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/net_rtl8169.h>
+
 #define MODULENAME "r8169"
 
 #define FIRMWARE_8168D_1	"rtl_nic/rtl8168d-1.fw"

@@ -6192,6 +6195,7 @@ static netdev_tx_t rtl8169_start_xmit(struct sk_buff *skb,
 	RTL_W8(tp, TxPoll, NPQ);
 
 	mmiowb();
+	trace_net_rtl8169_tx(tp->dev, tp->dirty_tx, tp->cur_tx, skb);
 
 	if (!TX_FRAGS_READY_FOR(tp, MAX_SKB_FRAGS)) {
 		/* Avoid wrongly optimistic queue wake-up: rtl_tx thread must

@@ -6297,6 +6301,7 @@ static void rtl_tx(struct net_device *dev, struct rtl8169_private *tp)
 		rtl8169_unmap_tx_skb(tp_to_dev(tp), tx_skb,
 				     tp->TxDescArray + entry);
 		if (status & LastFrag) {
+			trace_net_rtl8169_tx_done(dev, dirty_tx, tx_skb->skb);
 			u64_stats_update_begin(&tp->tx_stats.syncp);
 			tp->tx_stats.packets++;
 			tp->tx_stats.bytes += tx_skb->skb->len;

@@ -6447,6 +6452,7 @@ static int rtl_rx(struct net_device *dev, struct rtl8169_private *tp, u32 budget
 			if (skb->pkt_type == PACKET_MULTICAST)
 				dev->stats.multicast++;
 
+			trace_net_rtl8169_rx(dev, skb);
 			napi_gro_receive(&tp->napi, skb);
 
 			u64_stats_update_begin(&tp->rx_stats.syncp);

@@ -6473,6 +6479,8 @@ static irqreturn_t rtl8169_interrupt(int irq, void *dev_instance)
 	if (status == 0xffff || !(status & (RTL_EVENT_NAPI | tp->event_slow)))
 		return IRQ_NONE;
 
+	trace_net_rtl8169_interrupt(tp->napi.dev, status);
+
 	rtl_irq_disable(tp);
 	napi_schedule_irqoff(&tp->napi);

@@ -6554,6 +6562,7 @@ static int rtl8169_poll(struct napi_struct *napi, int budget)
 
 	status = rtl_get_events(tp);
 	rtl_ack_events(tp, status & ~tp->event_slow);
+	trace_net_rtl8169_poll(dev, status);
 
 	if (status & RTL_EVENT_NAPI_RX)
 		work_done = rtl_rx(dev, tp, (u32) budget);

diff --git a/include/trace/events/net_rtl8169.h b/include/trace/events/net_rtl8169.h
new file mode 100644
index 000000000000..15b3984c3939
--- /dev/null
+++ b/include/trace/events/net_rtl8169.h

@@ -0,0 +1,125 @@
+/* Realtek RTL8169 tracepoints
+ *
+ * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM net_rtl8169
+
+#if !defined(_TRACE_NET_RTL8169_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_NET_RTL8169_H
+
+#include <linux/tracepoint.h>
+#include <linux/errqueue.h>
+
+
+TRACE_EVENT(net_rtl8169_interrupt,
+	    TP_PROTO(struct net_device *netdev, u16 status),
+
+	    TP_ARGS(netdev, status),
+
+	    TP_STRUCT__entry(
+		    __field(u16,			status		)
+		    __array(char,			name, IFNAMSIZ	)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->status = status;
+		    memcpy(__entry->name, netdev->name, IFNAMSIZ);
+			   ),
+
+	    TP_printk("%s st=%x", __entry->name, __entry->status)
+	    );
+
+TRACE_EVENT(net_rtl8169_poll,
+	    TP_PROTO(struct net_device *netdev, u16 status),
+
+	    TP_ARGS(netdev, status),
+
+	    TP_STRUCT__entry(
+		    __field(u16,			status		)
+		    __array(char,			name, IFNAMSIZ	)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->status = status;
+		    memcpy(__entry->name, netdev->name, IFNAMSIZ);
+			   ),
+
+	    TP_printk("%s st=%x", __entry->name, __entry->status)
+	    );
+
+TRACE_EVENT(net_rtl8169_rx,
+	    TP_PROTO(struct net_device *netdev, struct sk_buff *skb),
+
+	    TP_ARGS(netdev, skb),
+
+	    TP_STRUCT__entry(
+		    __field(struct sk_buff *,		skb		)
+		    __array(char,			name, IFNAMSIZ	)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->skb = skb;
+		    memcpy(__entry->name, netdev->name, IFNAMSIZ);
+			   ),
+
+	    TP_printk("%s skb=%p", __entry->name, __entry->skb)
+	    );
+
+TRACE_EVENT(net_rtl8169_tx_done,
+	    TP_PROTO(struct net_device *netdev, unsigned int dirty_tx,
+		     struct sk_buff *skb),
+
+	    TP_ARGS(netdev, dirty_tx, skb),
+
+	    TP_STRUCT__entry(
+		    __field(struct sk_buff *,		skb)
+		    __field(unsigned int,		dirty_tx)
+		    __array(char,			name, IFNAMSIZ	)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->skb = skb;
+		    __entry->dirty_tx = dirty_tx;
+		    memcpy(__entry->name, netdev->name, IFNAMSIZ);
+			   ),
+
+	    TP_printk("%s p=%u skb=%p",
+		      __entry->name, __entry->dirty_tx, __entry->skb)
+	    );
+
+TRACE_EVENT(net_rtl8169_tx,
+	    TP_PROTO(struct net_device *netdev, unsigned int dirty_tx,
+		     unsigned int cur_tx, struct sk_buff *skb),
+
+	    TP_ARGS(netdev, dirty_tx, cur_tx, skb),
+
+	    TP_STRUCT__entry(
+		    __field(struct sk_buff *,		skb		)
+		    __field(unsigned int,		dirty_tx	)
+		    __field(unsigned int,		cur_tx		)
+		    __array(char,			name, IFNAMSIZ	)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->skb = skb;
+		    __entry->dirty_tx = dirty_tx;
+		    __entry->cur_tx = cur_tx;
+		    memcpy(__entry->name, netdev->name, IFNAMSIZ);
+			   ),
+
+	    TP_printk("%s p=%u-%u skb=%p",
+		      __entry->name, __entry->dirty_tx, __entry->cur_tx,
+		      __entry->skb)
+	    );
+
+#endif /* _TRACE_NET_RTL8169_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>

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