Merge branch 'tracing_test_fixes_v6.0' into 'release/v6.0'

Tracing test fixes (v6.0)

See merge request espressif/esp-idf!52328

examples/system/.build-test-rules.yml

@@ -1,17 +1,5 @@
 # Documentation: .gitlab/ci/README.md#manifest-file-to-control-the-buildtest-apps
 
-examples/system/app_trace_basic:
-  disable_test:
-    - if: IDF_TARGET == "esp32h21"
-      temporary: true
-      reason: not supported yet #TODO: OCD-1081
-    - if: IDF_TARGET == "esp32h4"
-      temporary: true
-      reason: not supported yet #TODO: OCD-1137
-  depends_components:
-    - esp_trace
-    - app_trace
-
 examples/system/base_mac_address:
   depends_components:
     - *common_components
@@ -68,21 +56,6 @@ examples/system/esp_timer:
     - *common_components
     - esp_timer
 
-examples/system/esp_trace_custom_library:
-  disable:
-    - if: SOC_USB_SERIAL_JTAG_SUPPORTED != 1
-      reason: example transport is USB Serial JTAG
-  disable_test:
-    - if: IDF_TARGET == "esp32h21"
-      temporary: true
-      reason: lack of runners
-    - if: IDF_TARGET == "esp32h4"
-      temporary: true
-      reason: lack of runners
-  depends_components:
-    - esp_trace
-    - freertos
-
 examples/system/eventfd:
   disable:
     - if: SOC_GPTIMER_SUPPORTED != 1 and (IDF_TARGET != "esp32" and (NIGHTLY_RUN != "1" or IDF_TARGET == "linux"))
@@ -116,21 +89,6 @@ examples/system/freertos/real_time_stats:
     - *common_components
     - freertos
 
-examples/system/gcov:
-  disable_test:
-    - if: IDF_TARGET == "esp32h21"
-      temporary: true
-      reason: not supported yet #TODO: OCD-1079
-    - if: IDF_TARGET == "esp32h4"
-      temporary: true
-      reason: not supported yet #TODO: OCD-1138
-    - if: IDF_TARGET == "esp32p4"
-      temporary: true
-      reason: p4 rev3 migration # TODO: IDF-14440
-  depends_components:
-    - esp_trace
-    - app_trace
-
 examples/system/heap_task_tracking:
   disable:
     - if: IDF_TARGET != "esp32c3" and (NIGHTLY_RUN != "1" or IDF_TARGET == "linux")
@@ -299,34 +257,6 @@ examples/system/select:
     - *common_components
     - vfs
 
-examples/system/sysview_tracing:
-  disable:
-    - if: SOC_GPTIMER_SUPPORTED != 1
-  disable_test:
-    - if: IDF_TARGET == "esp32h21"
-      temporary: true
-      reason: not supported yet #TODO: OCD-1082
-    - if: IDF_TARGET == "esp32h4"
-      temporary: true
-      reason: not supported yet #TODO: OCD-1136
-  depends_components:
-    - esp_trace
-    - app_trace
-
-examples/system/sysview_tracing_heap_log:
-  disable:
-    - if: SOC_GPTIMER_SUPPORTED != 1
-  disable_test:
-    - if: IDF_TARGET == "esp32h21"
-      temporary: true
-      reason: not supported yet #TODO: OCD-1082
-    - if: IDF_TARGET == "esp32h4"
-      temporary: true
-      reason: not supported yet #TODO: OCD-1136
-  depends_components:
-    - esp_trace
-    - app_trace
-
 examples/system/task_watchdog:
   disable:
     - if: IDF_TARGET != "esp32" and (NIGHTLY_RUN != "1" or IDF_TARGET == "linux")

examples/system/gcov/main/gcov_example_func.c

@@ -1,8 +0,0 @@
-#include <stdio.h>
-
-
-void blink_dummy_func(void)
-{
-    static int i;
-    printf("blink_dummy_func: Counter = %d\n", i++);
-}

examples/system/tracing/.build-test-rules.yml

@@ -0,0 +1,71 @@
+# Documentation: .gitlab/ci/README.md#manifest-file-to-control-the-buildtest-apps
+
+examples/system/tracing/app_trace_basic:
+  disable_test:
+    - if: IDF_TARGET == "esp32h21"
+      temporary: true
+      reason: not supported yet #TODO: OCD-1081
+    - if: IDF_TARGET == "esp32h4"
+      temporary: true
+      reason: not supported yet #TODO: OCD-1137
+  depends_components:
+    - esp_trace
+    - app_trace
+
+examples/system/tracing/esp_trace_custom_library:
+  disable:
+    - if: SOC_USB_SERIAL_JTAG_SUPPORTED != 1
+      reason: example transport is USB Serial JTAG
+  disable_test:
+    - if: IDF_TARGET == "esp32h21"
+      temporary: true
+      reason: lack of runners
+    - if: IDF_TARGET == "esp32h4"
+      temporary: true
+      reason: lack of runners
+  depends_components:
+    - esp_trace
+    - freertos
+
+examples/system/tracing/gcov:
+  disable_test:
+    - if: IDF_TARGET == "esp32h21"
+      temporary: true
+      reason: not supported yet #TODO: OCD-1079
+    - if: IDF_TARGET == "esp32h4"
+      temporary: true
+      reason: not supported yet #TODO: OCD-1138
+    - if: IDF_TARGET == "esp32p4"
+      temporary: true
+      reason: p4 rev3 migration # TODO: IDF-14440
+  depends_components:
+    - esp_trace
+    - app_trace
+
+examples/system/tracing/sysview_tracing:
+  disable:
+    - if: SOC_GPTIMER_SUPPORTED != 1
+  disable_test:
+    - if: IDF_TARGET == "esp32h21"
+      temporary: true
+      reason: not supported yet #TODO: OCD-1082
+    - if: IDF_TARGET == "esp32h4"
+      temporary: true
+      reason: not supported yet #TODO: OCD-1136
+  depends_components:
+    - esp_trace
+    - app_trace
+
+examples/system/tracing/sysview_tracing_heap_log:
+  disable:
+    - if: SOC_GPTIMER_SUPPORTED != 1
+  disable_test:
+    - if: IDF_TARGET == "esp32h21"
+      temporary: true
+      reason: not supported yet #TODO: OCD-1082
+    - if: IDF_TARGET == "esp32h4"
+      temporary: true
+      reason: not supported yet #TODO: OCD-1136
+  depends_components:
+    - esp_trace
+    - app_trace

examples/system/tracing/app_trace_to_plot/README.md

@@ -23,7 +23,7 @@ This example will assume that an ESP-WROVER-KIT is used.
 
 1. Connect the JTAG interface to the target board. For details about how to set up JTAG interface, please see [JTAG Debugging](https://docs.espressif.com/projects/esp-idf/en/latest/api-guides/jtag-debugging/index.html). Power up both the JTAG debugger and target board.
 
-2. To start the tcp socket server, you need to run `read_trace.py` tool under the `esp-idf/examples/system/app_trace_to_plot` path.
+2. To start the tcp socket server, you need to run `read_trace.py` tool under the `esp-idf/examples/system/tracing/app_trace_to_plot` path.
 
 3. After connecting JTAG interface and starting the tcp socket server, you need to [Run OpenOCD](https://docs.espressif.com/projects/esp-idf/en/latest/api-guides/jtag-debugging/index.html#run-openocd).
 
@@ -46,7 +46,7 @@ idf.py -p PORT flash monitor
 
 (Replace PORT with the name of the serial port to use.)
 
-**Run Plotting Tool** To plot data and open TCP socket, there is a tool named `read_trace.py` under the `examples/system/app_trace_to_plot` path. Run this tool in the terminal session with configured IDF development environment by entering the command below. This command opens a TCP socket and plots the given data when OpenOCD triggered to start App Trace. If you are running tool at first time, you need to install dash with `pip install dash` in the same terminal session after running configuring IDF development environment.
+**Run Plotting Tool** To plot data and open TCP socket, there is a tool named `read_trace.py` under the `examples/system/tracing/app_trace_to_plot` path. Run this tool in the terminal session with configured IDF development environment by entering the command below. This command opens a TCP socket and plots the given data when OpenOCD triggered to start App Trace. If you are running tool at first time, you need to install dash with `pip install dash` in the same terminal session after running configuring IDF development environment.
 
 ```bash
 python read_trace.py --plot-config data.json --source tcp://localhost:53535 --output-file data.log

examples/system/tracing/app_trace_to_plot/data.json

@@ -1,7 +1,7 @@
 {
   "//data.json": "Apptrace plotting config file for 'read_trace.py'",
   "//Summary and usage": "This file is used for apptrace plotting. You can use this json file with '--plot-config' parameter of the 'read_trace.py' file is to configure graphs for visualizing sensor data",
-  "//More information": "To get more information about apptrace plotting and configuration file, please check 'app_trace_to_plot' example in '../examples/system' and 'read_trace.py' file",
+  "//More information": "To get more information about apptrace plotting and configuration file, please check 'app_trace_to_plot' example in '../examples/system/tracing' and 'read_trace.py' file",
   "Temperature sensors": {
     "data_streams" : {
       "Outside temperature": {
@@ -27,7 +27,7 @@
       }
     },
     "xaxis_title": "Timestamp",
-    "yaxis_title": "Temperature in Celcius"
+    "yaxis_title": "Temperature in Celsius"
   },
   "Altitude sensors": {
     "data_streams" : {

examples/system/tracing/esp_trace_custom_library/README.md

@@ -3,7 +3,7 @@
 
 # ESP Trace External Library Integration Example
 
-This example shows the **minimal** set of files and configuration needed to plug a third-party trace library into the [`esp_trace`](../../../components/esp_trace) component using the public `CONFIG_ESP_TRACE_LIB_EXTERNAL` extension point. It is meant as a copy-paste starting point for vendors and users who want to integrate their own trace recorder (e.g. Percepio TraceRecorder, a custom CTF emitter, a printf-style logger, …) without patching ESP-IDF itself.
+This example shows the **minimal** set of files and configuration needed to plug a third-party trace library into the [`esp_trace`](../../../../components/esp_trace) component using the public `CONFIG_ESP_TRACE_LIB_EXTERNAL` extension point. It is meant as a copy-paste starting point for vendors and users who want to integrate their own trace recorder (e.g. Percepio TraceRecorder, a custom CTF emitter, a printf-style logger, …) without patching ESP-IDF itself.
 
 The example covers:
 
@@ -94,7 +94,7 @@ esp_trace_custom_library/
 
 ### 2. Providing the FreeRTOS trace hooks
 
-`esp_trace`'s public header [`esp_trace_freertos.h`](../../../components/esp_trace/include/esp_trace_freertos.h) is included from `FreeRTOSConfig.h`. When `CONFIG_ESP_TRACE_LIB_EXTERNAL=y` is set, it pulls in **your** `esp_trace_freertos_impl.h`:
+`esp_trace`'s public header [`esp_trace_freertos.h`](../../../../components/esp_trace/include/esp_trace_freertos.h) is included from `FreeRTOSConfig.h`. When `CONFIG_ESP_TRACE_LIB_EXTERNAL=y` is set, it pulls in **your** `esp_trace_freertos_impl.h`:
 
 ```c
 #if CONFIG_ESP_TRACE_LIB_EXTERNAL
@@ -177,7 +177,7 @@ Because the transport is USB-Serial-JTAG and the console is on UART (`CONFIG_ESP
 
 ## Runtime Control — `esp_trace_start` / `_stop` / `_flush`
 
-[`esp_trace.h`](../../../components/esp_trace/include/esp_trace.h) exposes three generic lifecycle calls that dispatch to the active encoder's vtable. The application uses only the public API — it never reaches into the external library:
+[`esp_trace.h`](../../../../components/esp_trace/include/esp_trace.h) exposes three generic lifecycle calls that dispatch to the active encoder's vtable. The application uses only the public API — it never reaches into the external library:
 
 ```c
 esp_trace_start();    // resume emission (also resets the delta baseline)
@@ -194,7 +194,7 @@ In this example the library boots with `s_enabled = false`, so nothing is emitte
 
 ## Other `esp_trace` Helpers
 
-Beyond what this example uses, [`esp_trace.h`](../../../components/esp_trace/include/esp_trace.h) and [`esp_trace_util.h`](../../../components/esp_trace/include/esp_trace_util.h) also expose:
+Beyond what this example uses, [`esp_trace.h`](../../../../components/esp_trace/include/esp_trace.h) and [`esp_trace_util.h`](../../../../components/esp_trace/include/esp_trace_util.h) also expose:
 
 * `esp_trace_is_host_connected()` — gate expensive work when no host is listening.
 * `esp_trace_get_link_type()` — returns `ESP_TRACE_LINK_DEBUG_PROBE`, `_UART`, or `_USB_SERIAL_JTAG`.
@@ -203,5 +203,5 @@ Beyond what this example uses, [`esp_trace.h`](../../../components/esp_trace/inc
 
 ## See Also
 
-* [`components/esp_trace/README.md`](../../../components/esp_trace/README.md) — full architecture overview and adapter API reference.
+* [`components/esp_trace/README.md`](../../../../components/esp_trace/README.md) — full architecture overview and adapter API reference.
 * [`examples/system/sysview_tracing`](../sysview_tracing) — a production-grade integration of SEGGER SystemView built on the same extension points.

examples/system/tracing/esp_trace_custom_library/components/ext_trace_lib/include/trace_FreeRTOS.h

@@ -36,6 +36,9 @@ void init_trace_lib(esp_trace_encoder_t *enc);
 void trace_lib_start(void);
 void trace_lib_stop(void);
 
+/* @brief Get the number of trace lines written to and dropped by the transport */
+void trace_lib_get_stats(uint32_t *written, uint32_t *dropped);
+
 /* Hook implementations — defined in trace_FreeRTOS.c.
  * Kept void*-typed to avoid depending on FreeRTOS types in this header. */
 void trace_lib_task_switched_in(void);

examples/system/tracing/esp_trace_custom_library/components/ext_trace_lib/src/adapter_encoder_ext_trace_lib.c

@@ -85,14 +85,6 @@ static esp_err_t stop(esp_trace_encoder_t *enc)
     return ESP_OK;
 }
 
-static esp_err_t flush(esp_trace_encoder_t *enc)
-{
-    if (!enc || !enc->tp || !enc->tp->vt->flush_nolock) {
-        return ESP_ERR_NOT_SUPPORTED;
-    }
-    return enc->tp->vt->flush_nolock(enc->tp);
-}
-
 /**
  * @brief Panic handler
  *
@@ -104,7 +96,11 @@ static esp_err_t flush(esp_trace_encoder_t *enc)
 static void panic_handler(esp_trace_encoder_t *enc, const void *info)
 {
     (void)info;
-    flush(enc);
+
+    /* No lock here, the panicking core may already hold it */
+    if (enc && enc->tp && enc->tp->vt->flush_nolock) {
+        enc->tp->vt->flush_nolock(enc->tp);
+    }
 }
 
 static unsigned int take_lock(esp_trace_encoder_t *enc, uint32_t tmo_us)
@@ -127,6 +123,34 @@ static void give_lock(esp_trace_encoder_t *enc, unsigned int int_state)
     esp_trace_lock_give(&ctx->lock);
 }
 
+/* Total time for the flush, split over several flush_nolock() calls */
+#define EXT_TRACE_LIB_FLUSH_TMO_US  (1000000)
+
+static esp_err_t flush(esp_trace_encoder_t *enc)
+{
+    if (!enc || !enc->tp || !enc->tp->vt->flush_nolock) {
+        return ESP_ERR_NOT_SUPPORTED;
+    }
+
+    /* One call may be too short to send all the data, so repeat it and release
+     * the lock in between to keep interrupts enabled */
+    esp_trace_tmo_t tmo;
+    esp_trace_tmo_init(&tmo, EXT_TRACE_LIB_FLUSH_TMO_US);
+
+    esp_err_t err;
+    do {
+        unsigned int int_state = take_lock(enc, ESP_TRACE_TMO_INFINITE);
+        err = enc->tp->vt->flush_nolock(enc->tp);
+        give_lock(enc, int_state);
+
+        if (err != ESP_ERR_TIMEOUT) {
+            break;  /* done, or an error that repeating cannot fix */
+        }
+    } while (esp_trace_tmo_check(&tmo) == ESP_OK);
+
+    return err;
+}
+
 static const esp_trace_encoder_vtable_t s_ext_trace_lib_vt = {
     .init                  = init,
     .write                 = write,

examples/system/tracing/esp_trace_custom_library/components/ext_trace_lib/src/trace_FreeRTOS.c

@@ -35,6 +35,8 @@ static esp_trace_encoder_t *s_enc = NULL;
 static uint32_t s_ts_freq_hz = 1000000;   /* default assume 1 MHz */
 static uint32_t s_last_ts = 0;
 static volatile bool s_enabled = false;
+static uint32_t s_written = 0;
+static uint32_t s_dropped = 0;
 
 void init_trace_lib(esp_trace_encoder_t *enc)
 {
@@ -87,12 +89,26 @@ static void encode(const char *type, const char *detail)
         if (n >= (int)sizeof(line)) {
             n = (int)sizeof(line) - 1;
         }
-        esp_trace_write(s_esp_trace_handle, line, (size_t)n, 0);
+        if (esp_trace_write(s_esp_trace_handle, line, (size_t)n, 0) == ESP_OK) {
+            s_written++;
+        } else {
+            s_dropped++;  /* transport buffer was full, line dropped */
+        }
     }
 
     s_enc->vt->give_lock(s_enc, int_state);
 }
 
+void trace_lib_get_stats(uint32_t *written, uint32_t *dropped)
+{
+    if (written) {
+        *written = s_written;
+    }
+    if (dropped) {
+        *dropped = s_dropped;
+    }
+}
+
 void trace_lib_task_switched_in(void)
 {
     TaskHandle_t h = xTaskGetCurrentTaskHandle();

examples/system/tracing/esp_trace_custom_library/main/app_main.c

@@ -5,6 +5,7 @@
  */
 #include "sdkconfig.h"
 
+#include <inttypes.h>
 #include <stdio.h>
 #include <string.h>
 
@@ -13,6 +14,7 @@
 #include "freertos/queue.h"
 #include "esp_log.h"
 #include "esp_trace.h"
+#include "trace_FreeRTOS.h"
 
 static const char *TAG = "main";
 
@@ -70,7 +72,16 @@ void app_main(void)
     vTaskDelay(1000 / portTICK_PERIOD_MS);
 
     esp_trace_stop();
-    esp_trace_flush();
+    esp_err_t err = esp_trace_flush();
+
+    /* Logged from task context, so it goes to the console UART and not to the
+     * trace port. Shows whether the device sent the trace data or not. */
+    uint32_t written = 0;
+    uint32_t dropped = 0;
+    trace_lib_get_stats(&written, &dropped);
+    ESP_LOGI(TAG, "Trace flush: %s, host connected: %d, lines written: %" PRIu32 ", dropped: %" PRIu32,
+             esp_err_to_name(err), (int)esp_trace_is_host_connected(esp_trace_get_active_handle()),
+             written, dropped);
 
     ESP_LOGI(TAG, "End of trace session");
 }

examples/system/tracing/esp_trace_custom_library/pytest_esp_trace_custom_library.py

@@ -76,7 +76,6 @@ def _validate_trace_data(trace_log_path: str) -> None:
 
 def _capture_trace(ser: serial.Serial, trace_log_path: str, capture_s: float = 5.0) -> None:
     """Capture trace output from the USB-Serial-JTAG endpoint."""
-    ser.reset_input_buffer()
     with open(trace_log_path, 'w+b') as f:
         end_time = time.time() + capture_s
         while time.time() < end_time:
@@ -107,10 +106,13 @@ def _capture_trace(ser: serial.Serial, trace_log_path: str, capture_s: float = 5
 def test_esp_trace_ext_lib_usj(dut: IdfDut) -> None:
     dut.expect('Start of trace session', timeout=5)
 
-    time.sleep(1)  # wait for USJ port to be ready
+    # Open the port before the DUT starts tracing
     usj_port = '/dev/serial_ports/ttyACM-esp32'
-    ser = serial.Serial(usj_port, baudrate=1000000, timeout=10)
     trace_log_path = os.path.join(dut.logdir, 'ext_trace.log')
+    time.sleep(1)  # Wait for the USJ port to be ready
+    with serial.Serial(usj_port, baudrate=1000000, timeout=10) as ser:
+        # Discard data from before this test, the DUT is not tracing yet
+        ser.reset_input_buffer()
+        _capture_trace(ser, trace_log_path)
 
-    _capture_trace(ser, trace_log_path)
     _validate_trace_data(trace_log_path)

examples/system/tracing/esp_trace_custom_library/sdkconfig.defaults

@@ -3,4 +3,4 @@ CONFIG_ESP_TRACE_LIB_EXTERNAL=y
 CONFIG_ESP_TRACE_TS_SOURCE_ESP_TIMER=y
 CONFIG_ESP_CONSOLE_SECONDARY_NONE=y
 CONFIG_ESP_TRACE_TRANSPORT_USB_SERIAL_JTAG=y
-CONFIG_ESP_TRACE_USJ_TX_BUFFER_SIZE=32768
+CONFIG_ESP_TRACE_USJ_TX_BUFFER_SIZE=16384

examples/system/tracing/gcov/components/sample/some_funcs.c

@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Unlicense OR CC0-1.0
+ */
 #include <stdio.h>
 
 

examples/system/tracing/gcov/main/gcov_example_func.c

@@ -0,0 +1,13 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Unlicense OR CC0-1.0
+ */
+#include <stdio.h>
+
+
+void blink_dummy_func(void)
+{
+    static int i;
+    printf("blink_dummy_func: Counter = %d\n", i++);
+}

examples/system/tracing/gcov/main/gcov_example_main.c

@@ -1,11 +1,8 @@
-/* Blink Example with covergae info
-
-   This example code is in the Public Domain (or CC0 licensed, at your option.)
-
-   Unless required by applicable law or agreed to in writing, this
-   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
-   CONDITIONS OF ANY KIND, either express or implied.
-*/
+/*
+ * SPDX-FileCopyrightText: 2026 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Unlicense OR CC0-1.0
+ */
 #include <stdio.h>
 #include "freertos/FreeRTOS.h"
 #include "freertos/task.h"

examples/system/tracing/sysview_tracing/main/sysview_tracing.c

@@ -1,11 +1,8 @@
-/* Application Trace to Host Example
-
-   This example code is in the Public Domain (or CC0 licensed, at your option.)
-
-   Unless required by applicable law or agreed to in writing, this
-   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
-   CONDITIONS OF ANY KIND, either express or implied.
-*/
+/*
+ * SPDX-FileCopyrightText: 2026 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Unlicense OR CC0-1.0
+ */
 
 #include "esp_err.h"
 #include "sdkconfig.h"

examples/system/tracing/sysview_tracing/pytest_sysview_tracing.py

@@ -16,6 +16,24 @@ if typing.TYPE_CHECKING:
     from conftest import OpenOCD
 
 
+STOP_EVENT_ID = 0x0B  # SYSVIEW_EVTID_TRACE_STOP
+
+
+def _assert_has_stop_record(segment: bytes, label: str) -> None:
+    """Assert a SysView data segment ends with a TRACE_STOP record.
+
+    A STOP record is the STOP event ID followed by a variable-length timestamp
+    delta. Walk back over the trailing continuation bytes (0x80 bit set) to find
+    the event ID, since its offset is not fixed.
+    """
+    size = len(segment)
+    assert size >= 2, f'{label}: segment too small to contain STOP record'
+    i = size - 2
+    while i >= 0 and (segment[i] & 0x80):
+        i -= 1
+    assert i >= 0 and segment[i] == STOP_EVENT_ID, f'{label}: does not end with a TRACE_STOP record'
+
+
 def _validate_trace_data(trace_log: list[str], target: str, is_uart: bool = False) -> None:
     """Validate SysView trace data in log file(s).
 
@@ -24,23 +42,14 @@ def _validate_trace_data(trace_log: list[str], target: str, is_uart: bool = Fals
         target: Target chip name (e.g., 'esp32', 'esp32s3')
         is_uart: If True, also validate STOP record at end of file
     """
-    STOP_EVENT_ID = 0x0B  # SYSVIEW_EVTID_TRACE_STOP
-
     for idx, log in enumerate(trace_log):
         with open(log, 'rb') as f:
             content = f.read()
-            search_str = f'N=FreeRTOS Application,D={target},C=core{idx},O=FreeRTOS'.encode()
-            assert search_str in content, f'SysView trace data not found in {log}'
-            # The file must end with a TRACE_STOP record: the STOP event ID
-            # followed by a variable-length timestamp delta. Walk back
-            # over the trailing continuation bytes (0x80 bit set)
-            # to find the event ID, since its offset is not fixed.
-            size = len(content)
-            assert size >= 2, 'Trace file too small to contain STOP record'
-            i = size - 2
-            while i >= 0 and (content[i] & 0x80):
-                i -= 1
-            assert i >= 0 and content[i] == STOP_EVENT_ID, 'STOP record does not start with STOP eventID'
+        search_str = f'N=FreeRTOS Application,D={target},C=core{idx},O=FreeRTOS'.encode()
+        assert search_str in content, f'SysView trace data not found in {log}'
+        # Each core is captured to its own file; require each to end
+        # with its own TRACE_STOP record.
+        _assert_has_stop_record(content, f'core{idx}')
 
 
 def _capture_sysview_trace(ser: serial.Serial, trace_log_path: str) -> None:
@@ -125,8 +134,9 @@ def _test_sysview_tracing_jtag(openocd_dut: 'OpenOCD', dut: IdfDut) -> None:
         dut.expect('example: Created task')  # dut has been restarted by gdb since the last dut.expect()
         dut_expect_task_event()
 
-        # Do a sleep while sysview samples are captured.
-        time.sleep(3)
+        # Capture sysview samples and keep reading telnet so OpenOCD's blocking log writes don't stall its
+        # main loop and leave the 'stop' below unserviced.
+        openocd.consume_output(3)
         openocd.write('esp sysview stop')
         openocd.apptrace_wait_stop()
 
@@ -173,7 +183,7 @@ def test_sysview_tracing_uart(dut: IdfDut) -> None:
 def test_sysview_tracing_usj_serial(dut: IdfDut) -> None:
     time.sleep(1)  # wait for USJ port to be ready
     usj_port = '/dev/serial_ports/ttyACM-esp32'
-    ser = serial.Serial(usj_port, baudrate=1000000, timeout=10)
     trace_log = [os.path.join(dut.logdir, 'sys_log_usj.svdat')]  # pylint: disable=protected-access
-    _capture_sysview_trace(ser, trace_log[0])
-    _validate_trace_data(trace_log, dut.target, is_uart=True)
+    with serial.Serial(usj_port, baudrate=1000000, timeout=10) as ser:
+        _capture_sysview_trace(ser, trace_log[0])
+        _validate_trace_data(trace_log, dut.target, is_uart=True)

examples/system/tracing/sysview_tracing/sdkconfig.ci.sysview_usj

@@ -1,3 +1,4 @@
 CONFIG_ESP_CONSOLE_SECONDARY_NONE=y
 CONFIG_ESP_TRACE_TRANSPORT_USB_SERIAL_JTAG=y
 CONFIG_USE_CUSTOM_EVENT_ID=y
+CONFIG_ESP_TRACE_USJ_TX_BUFFER_SIZE=16384

examples/system/tracing/sysview_tracing_heap_log/main/sysview_heap_log.c

@@ -1,11 +1,8 @@
-/* Application Trace to Host Example
-
-   This example code is in the Public Domain (or CC0 licensed, at your option.)
-
-   Unless required by applicable law or agreed to in writing, this
-   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
-   CONDITIONS OF ANY KIND, either express or implied.
-*/
+/*
+ * SPDX-FileCopyrightText: 2026 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Unlicense OR CC0-1.0
+ */
 
 #include "sdkconfig.h"
 #include <inttypes.h>