move retransmits back into tcp_stats_t

DataDog · Nov 5, 2024 · 5917430 · 5917430
1 parent 4314c5f
commit 5917430
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Showing 6 changed files with 16 additions and 15 deletions.
diff --git a/pkg/network/ebpf/c/tracer/events.h b/pkg/network/ebpf/c/tracer/events.h
@@ -64,7 +64,7 @@ static __always_inline void cleanup_conn(void *ctx, conn_tuple_t *tup, struct so
         conn.tup.pid = 0;
         retrans = bpf_map_lookup_elem(&tcp_retransmits, &(conn.tup));
         if (retrans) {
-            conn.tcp_retransmits = *retrans;
+            conn.tcp_stats.retransmits = *retrans;
             bpf_map_delete_elem(&tcp_retransmits, &(conn.tup));
         }
         conn.tup.pid = tup->pid;

diff --git a/pkg/network/ebpf/c/tracer/tracer.h b/pkg/network/ebpf/c/tracer/tracer.h
@@ -66,6 +66,7 @@ typedef enum {
 typedef struct {
     __u32 rtt;
     __u32 rtt_var;
+    __u32 retransmits;
 
     // Bit mask containing all TCP state transitions tracked by our tracer
     __u16 state_transitions;
@@ -74,9 +75,9 @@ typedef struct {
 // Full data for a tcp connection
 typedef struct {
     conn_tuple_t tup;
-    conn_stats_ts_t conn_stats;
+    // move tcp_stats here to align conn_stats on a cacheline boundary
     tcp_stats_t tcp_stats;
-    __u32 tcp_retransmits;
+    conn_stats_ts_t conn_stats;
 } conn_t;
 
 typedef struct {

diff --git a/pkg/network/ebpf/kprobe_types_linux.go b/pkg/network/ebpf/kprobe_types_linux.go
diff --git a/pkg/network/tracer/connection/ebpf_tracer.go b/pkg/network/tracer/connection/ebpf_tracer.go
@@ -427,10 +427,10 @@ func (t *ebpfTracer) GetConnections(buffer *network.ConnectionBuffer, filter fun
 		}
 
 		if t.getTCPStats(tcp, key) {
-			updateTCPStats(conn, tcp, 0)
+			updateTCPStats(conn, tcp)
 		}
-		if retrans, ok := t.getTCPRetransmits(key, seen); ok {
-			updateTCPStats(conn, nil, retrans)
+		if retrans, ok := t.getTCPRetransmits(key, seen); ok && conn.Type == network.TCP {
+			conn.Monotonic.Retransmits = retrans
 		}
 
 		*buffer.Next() = *conn
@@ -791,13 +791,13 @@ func populateConnStats(stats *network.ConnectionStats, t *netebpf.ConnTuple, s *
 	}
 }
 
-func updateTCPStats(conn *network.ConnectionStats, tcpStats *netebpf.TCPStats, retransmits uint32) {
+func updateTCPStats(conn *network.ConnectionStats, tcpStats *netebpf.TCPStats) {
 	if conn.Type != network.TCP {
 		return
 	}
 
-	conn.Monotonic.Retransmits = retransmits
 	if tcpStats != nil {
+		conn.Monotonic.Retransmits = tcpStats.Retransmits
 		conn.Monotonic.TCPEstablished = tcpStats.State_transitions >> netebpf.Established & 1
 		conn.Monotonic.TCPClosed = tcpStats.State_transitions >> netebpf.Close & 1
 		conn.RTT = tcpStats.Rtt

diff --git a/pkg/network/tracer/connection/perf_batching.go b/pkg/network/tracer/connection/perf_batching.go
@@ -62,7 +62,7 @@ func (p *perfBatchManager) ExtractBatchInto(buffer *network.ConnectionBuffer, b
 	for rc := p.extractor.NextConnection(b); rc != nil; rc = p.extractor.NextConnection(b) {
 		conn := buffer.Next()
 		populateConnStats(conn, &rc.Tup, &rc.Conn_stats, p.ch)
-		updateTCPStats(conn, &rc.Tcp_stats, rc.Tcp_retransmits)
+		updateTCPStats(conn, &rc.Tcp_stats)
 	}
 }
 
@@ -80,7 +80,7 @@ func (p *perfBatchManager) GetPendingConns(buffer *network.ConnectionBuffer) {
 		for rc := p.extractor.NextConnection(b); rc != nil; rc = p.extractor.NextConnection(b) {
 			c := buffer.Next()
 			populateConnStats(c, &rc.Tup, &rc.Conn_stats, p.ch)
-			updateTCPStats(c, &rc.Tcp_stats, rc.Tcp_retransmits)
+			updateTCPStats(c, &rc.Tcp_stats)
 		}
 	}
 	p.extractor.CleanupExpiredState(time.Now())

diff --git a/pkg/network/tracer/connection/tcp_close_consumer.go b/pkg/network/tracer/connection/tcp_close_consumer.go
@@ -85,7 +85,7 @@ func (c *tcpCloseConsumer) extractConn(data []byte) {
 	ct := (*netebpf.Conn)(unsafe.Pointer(&data[0]))
 	conn := c.buffer.Next()
 	populateConnStats(conn, &ct.Tup, &ct.Conn_stats, c.ch)
-	updateTCPStats(conn, &ct.Tcp_stats, ct.Tcp_retransmits)
+	updateTCPStats(conn, &ct.Tcp_stats)
 }
 
 func (c *tcpCloseConsumer) Start(callback func(*network.ConnectionStats)) {