try optimizing alignment

bpf/types.h

@@ -75,51 +75,51 @@ typedef enum direction_t {
 const u8 ip4in6[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff};
 
 typedef struct flow_metrics_t {
-    struct bpf_spin_lock lock;
+    // Flow start and end times as monotomic timestamps in nanoseconds
+    // as output from bpf_ktime_get_ns()
+    u64 start_mono_time_ts;
+    u64 end_mono_time_ts;
+    u64 bytes;
+    u32 packets;
     u16 eth_protocol;
+    // TCP Flags from https://www.ietf.org/rfc/rfc793.txt
+    u16 flags;
     // L2 data link layer
     u8 src_mac[ETH_ALEN];
     u8 dst_mac[ETH_ALEN];
     // OS interface index
     u32 if_index_first_seen;
+    struct bpf_spin_lock lock;
     u8 direction_first_seen;
-    u32 packets;
-    u64 bytes;
-    // Flow start and end times as monotomic timestamps in nanoseconds
-    // as output from bpf_ktime_get_ns()
-    u64 start_mono_time_ts;
-    u64 end_mono_time_ts;
-    // TCP Flags from https://www.ietf.org/rfc/rfc793.txt
-    u16 flags;
     // The positive errno of a failed map insertion that caused a flow
     // to be sent via ringbuffer.
     // 0 otherwise
     // https://chromium.googlesource.com/chromiumos/docs/+/master/constants/errnos.md
     u8 errno;
     u8 dscp;
     struct dns_record_t {
+        u64 latency;
         u16 id;
         u16 flags;
-        u64 latency;
         u8 errno;
     } dns_record;
 } flow_metrics;
 
 typedef struct additional_metrics_t {
     struct pkt_drops_t {
-        u32 packets;
         u64 bytes;
+        u32 packets;
+        u32 latest_drop_cause;
         u16 latest_flags;
         u8 latest_state;
-        u32 latest_drop_cause;
     } pkt_drops;
     u64 flow_rtt;
-    u8 network_events_idx;
     u8 network_events[MAX_NETWORK_EVENTS][MAX_EVENT_MD];
     struct observed_intf_t {
         u8 direction;
         u32 if_index;
     } __attribute__((packed)) observed_intf[MAX_OBSERVED_INTERFACES];
+    u8 network_events_idx;
     u8 nb_observed_intf;
 } additional_metrics;