feat(rtps): menuconfig option for the transport task priority

components/rtps/CMakeLists.txt

@@ -91,6 +91,16 @@ foreach(knob ${RTPS_LIMIT_KNOBS})
   endif()
 endforeach()
 
+# Transport task priority (Kconfig "Transport task priority"): a nonzero value
+# overrides the selected profile's THREAD_POOL_READER_PRIO, which the transport
+# gives its worker pool and reactor tasks. 0 keeps the profile's value.
+if(DEFINED CONFIG_RTPS_THREAD_POOL_READER_PRIO
+   AND NOT "${CONFIG_RTPS_THREAD_POOL_READER_PRIO}" STREQUAL ""
+   AND NOT "${CONFIG_RTPS_THREAD_POOL_READER_PRIO}" STREQUAL "0")
+  target_compile_definitions(${COMPONENT_LIB} PUBLIC
+    "RTPS_CFG_THREAD_POOL_READER_PRIO=${CONFIG_RTPS_THREAD_POOL_READER_PRIO}")
+endif()
+
 # Cross-limit capacity check (mirrors lib/espp.cmake): every participant
 # consumes 1 stateless writer/reader + 2 stateful writers/readers from the
 # GLOBAL pools for its builtin discovery endpoints. Effective value = the

components/rtps/Kconfig

@@ -178,6 +178,29 @@ menu "RTPS"
 
     endmenu
 
+    menu "Transport task priority (advanced)"
+        config RTPS_THREAD_POOL_READER_PRIO
+            int "THREAD_POOL_READER_PRIO: worker pool and reactor (0 = profile default)"
+            default 0
+            range 0 24
+            help
+                FreeRTOS priority of the transport's tasks: the worker pool
+                ("rtps_worker_<n>"), which sends and receives all RTPS traffic
+                (publish() only queues a sample; a worker sends it) and runs
+                every reader and matched callback, and the reactor
+                ("rtps_reactor"), the select() loop that hands received
+                datagrams to the pool. 0 keeps the selected profile's value
+                (5 on the embedded profile, 3 on the host profiles).
+
+                Raise it when a busy task of higher priority (a UI renderer, a
+                long computation) can run on the same core as these tasks:
+                until it yields, nothing is sent or received. Bands (QosBand)
+                order work inside the pool and cannot help when the pool's
+                tasks are not scheduled. The callbacks then run at this
+                priority too, so keep them short.
+
+    endmenu
+
     config RTPS_STORAGE_DYNAMIC
         bool "Use dynamic (heap) history/queue storage"
         default n

components/rtps/README.md

@@ -164,6 +164,7 @@ via `include/rtps/config.hpp`.
 | `RTPS_STORAGE_DYNAMIC` | off on ESP32 / on host | Static `std::array` history (zero-heap, drop-oldest) vs heap-backed `std::deque` (grows). Orthogonal to the profile. |
 | `RTPS_ENABLE_FRAGMENTATION` | off on ESP32 / on host | DATA_FRAG for samples > ~64 KB (interoperates with FastDDS/ROS 2). |
 | `RTPS_ENABLE_RPC` | on (default) | Compile in services + actions (RMI/AMI). Disable to drop that code + its threads on a pure-pub/sub device. |
+| `RTPS_THREAD_POOL_READER_PRIO` | 0 = profile default (5 on ESP32) | FreeRTOS priority of the transport's worker pool and reactor tasks, which send and receive all traffic (see [Priority scheduling](#priority-scheduling-bands-dedicated-ports-dscp)). |
 
 The domain id, announcement/heartbeat periods, and pool sizes live in the profile
 headers.
@@ -251,6 +252,15 @@ of its underlying service/topic endpoints (note a ROS action server is ~8
 endpoints — more than the default ration, so most fall back to deferred
 dispatch unless the cap is raised).
 
+Bands order work *inside* the transport's worker pool. The pool's tasks
+themselves (`rtps_worker_<n>`, plus the `rtps_reactor` `select()` loop) run at
+the profile's `THREAD_POOL_READER_PRIO` (5 on ESP32) on no particular core.
+Every send and receive goes through them (`publish()` only queues the sample),
+so a busy task of higher priority on their core stalls all traffic until it
+yields. On ESP-IDF, menuconfig `RTPS -> Transport task priority (advanced)`
+sets their priority; `0` keeps the profile default. The reader and matched
+callbacks then run at that priority too, so keep them short.
+
 ---
 
 ## ESPP component dependencies

components/rtps/include/rtps/config_desktop.hpp

@@ -188,7 +188,12 @@ const int MAX_NUM_UDP_CONNECTIONS = RTPS_CFG_MAX_NUM_UDP_CONNECTIONS;
 const int THREAD_POOL_NUM_WRITERS = 2;
 const int THREAD_POOL_NUM_READERS = 2;
 const int THREAD_POOL_WRITER_PRIO = 3;
-const int THREAD_POOL_READER_PRIO = 3;
+// The transport's worker pool and reactor tasks (EsppTransport). On ESP-IDF,
+// menuconfig RTPS -> Transport task priority overrides it.
+#ifndef RTPS_CFG_THREAD_POOL_READER_PRIO
+#define RTPS_CFG_THREAD_POOL_READER_PRIO 3
+#endif
+const int THREAD_POOL_READER_PRIO = RTPS_CFG_THREAD_POOL_READER_PRIO;
 const int THREAD_POOL_WORKLOAD_QUEUE_LENGTH_USERTRAFFIC = 32;
 const int THREAD_POOL_WORKLOAD_QUEUE_LENGTH_METATRAFFIC = 32;
 

components/rtps/include/rtps/config_esp32.hpp

@@ -163,7 +163,12 @@ const int MAX_NUM_UDP_CONNECTIONS = RTPS_CFG_MAX_NUM_UDP_CONNECTIONS;
 const int THREAD_POOL_NUM_WRITERS = 2;
 const int THREAD_POOL_NUM_READERS = 2;
 const int THREAD_POOL_WRITER_PRIO = 5;
-const int THREAD_POOL_READER_PRIO = 5;
+// The transport's worker pool and reactor tasks (EsppTransport). On ESP-IDF,
+// menuconfig RTPS -> Transport task priority overrides it.
+#ifndef RTPS_CFG_THREAD_POOL_READER_PRIO
+#define RTPS_CFG_THREAD_POOL_READER_PRIO 5
+#endif
+const int THREAD_POOL_READER_PRIO = RTPS_CFG_THREAD_POOL_READER_PRIO;
 const int THREAD_POOL_WORKLOAD_QUEUE_LENGTH_USERTRAFFIC = 60;
 const int THREAD_POOL_WORKLOAD_QUEUE_LENGTH_METATRAFFIC = 60;
 

components/rtps/include/rtps/config_host_large.hpp

@@ -182,7 +182,12 @@ const int MAX_NUM_UDP_CONNECTIONS = RTPS_CFG_MAX_NUM_UDP_CONNECTIONS;
 const int THREAD_POOL_NUM_WRITERS = 2;
 const int THREAD_POOL_NUM_READERS = 2;
 const int THREAD_POOL_WRITER_PRIO = 3;
-const int THREAD_POOL_READER_PRIO = 3;
+// The transport's worker pool and reactor tasks (EsppTransport). On ESP-IDF,
+// menuconfig RTPS -> Transport task priority overrides it.
+#ifndef RTPS_CFG_THREAD_POOL_READER_PRIO
+#define RTPS_CFG_THREAD_POOL_READER_PRIO 3
+#endif
+const int THREAD_POOL_READER_PRIO = RTPS_CFG_THREAD_POOL_READER_PRIO;
 const int THREAD_POOL_WORKLOAD_QUEUE_LENGTH_USERTRAFFIC = 64;
 const int THREAD_POOL_WORKLOAD_QUEUE_LENGTH_METATRAFFIC = 64;