rfnoc: Enable drop counter on chdr_ctrl_endpoint

This class has a member _num_drops, which can be read out using the
get_num_drops() API call. However, when dropping packets, this counter
was not incremented, which is fixed now.

This also includes a very minor optimization from 2 map<> lookups to
1 lookup (they are in O(log N)). Since there are usually a small
two-digit number of endpoints connected to the async message receiver,
this change is not expected to yield major improvements, but the lookup
*is* in a hot loop.

2 files changed, 23 insertions, 4 deletions

diff --git a/host/lib/include/uhdlib/rfnoc/chdr_ctrl_endpoint.hpp b/host/lib/include/uhdlib/rfnoc/chdr_ctrl_endpoint.hpp
index 61358fa2f..65db20e5a 100644
--- a/host/lib/include/uhdlib/rfnoc/chdr_ctrl_endpoint.hpp
+++ b/host/lib/include/uhdlib/rfnoc/chdr_ctrl_endpoint.hpp
@@ -42,6 +42,11 @@ public:
         const clock_iface& timebase_clk) = 0;
 
     //! Returns the number of dropped packets due to misclassification
+    //
+    // This includes packets that are not valid CHDR as well as packets that
+    // are valid CHDR, but have no known/valid endpoint. Correctly classified
+    // packets may still be invalid, but they don't get counted here, they are
+    // handled in ctrlport_endpoint.
     virtual size_t get_num_drops() const = 0;
 
     //! Creates a control endpoint object
diff --git a/host/lib/rfnoc/chdr_ctrl_endpoint.cpp b/host/lib/rfnoc/chdr_ctrl_endpoint.cpp
index 7d9bb8d1b..8194c7a93 100644
--- a/host/lib/rfnoc/chdr_ctrl_endpoint.cpp
+++ b/host/lib/rfnoc/chdr_ctrl_endpoint.cpp
@@ -32,6 +32,7 @@ public:
         sep_id_t my_epid)
         : _my_epid(my_epid)
         , _xport(xport)
+        , _num_drops(0)
         , _send_pkt(pkt_factory.make_ctrl())
         , _recv_pkt(pkt_factory.make_ctrl())
         , _stop_recv_thread(false)
@@ -135,11 +136,23 @@ private:
                     _recv_pkt->refresh(buff->data());
                     const ctrl_payload payload = _recv_pkt->get_payload();
                     ep_map_key_t key{payload.src_epid, payload.dst_port};
-                    if (_endpoint_map.find(key) != _endpoint_map.end()) {
-                        _endpoint_map.at(key)->handle_recv(payload);
+                    auto ep_iter = _endpoint_map.find(key);
+                    if (ep_iter != _endpoint_map.end()) {
+                        ep_iter->second->handle_recv(payload);
+                    } else {
+                        UHD_LOG_WARNING("RFNOC",
+                            "chdr_ctrl_endpoint: Received async message for unknown "
+                            "destination. Source EPID: "
+                                << payload.src_epid
+                                << " Destination Port: " << payload.dst_port);
+                        _num_drops++;
                     }
                 } catch (...) {
                     // Ignore all errors
+                    UHD_LOG_DEBUG("RFNOC",
+                        "chdr_ctrl_endpoint: Unidentified error in async message handler "
+                        "loop.");
+                    _num_drops++;
                 }
                 _xport->release_recv_buff(std::move(buff));
             } else {
@@ -170,8 +183,9 @@ private:
     chdr_ctrl_xport::sptr _xport;
     // The curent sequence number for a send packet
     size_t _send_seqnum = 0;
-    // The number of packets dropped
-    size_t _num_drops = 0;
+    // The number of packets dropped due to misclassification. See also
+    // get_num_drops()
+    std::atomic<size_t> _num_drops;
     // Packet containers
     chdr_ctrl_packet::uptr _send_pkt;
     chdr_ctrl_packet::cuptr _recv_pkt;