sample mismatched server id in tpr stats bpf program

Summary: for easier debugging Reviewed By: avasylev Differential Revision: D65948620 fbshipit-source-id: 80a2005302b6c994c60a34859b48df9907e81bc7
facebookincubator · Nov 22, 2024 · 41de049 · 41de049
1 parent 0797b52
commit 41de049
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diff --git a/katran/decap/tc_bpf/tc_decap_stats.bpf.c b/katran/decap/tc_bpf/tc_decap_stats.bpf.c
@@ -64,6 +64,12 @@ __attribute__((__always_inline__)) static inline void validate_tpr_server_id(
         data_stats->tpr_total += 1;
         if (*server_id_host != server_id) {
           data_stats->tpr_misrouted += 1;
+          __u32 sid_sample_key = 0;
+          __u64* server_id_sample =
+              bpf_map_lookup_elem(&tpr_mism_sid, &sid_sample_key);
+          if (server_id_sample) {
+            *server_id_sample = server_id;
+          }
         }
       }
     }

diff --git a/katran/decap/tc_bpf/tc_decap_stats_maps.h b/katran/decap/tc_bpf/tc_decap_stats_maps.h
@@ -49,4 +49,13 @@ struct {
   __uint(map_flags, NO_FLAGS);
 } tpr_server_id SEC(".maps");
 
+// map for sampled tpr mismatched server ids
+struct {
+  __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
+  __type(key, __u32);
+  __type(value, __u64);
+  __uint(max_entries, DECAP_STATS_MAP_SIZE);
+  __uint(map_flags, NO_FLAGS);
+} tpr_mism_sid SEC(".maps");
+
 #endif // of __DECAP_STATS_MAPS_H