dlt-qnx-system: prevent message loss in high load situations

CMakeLists.txt

@@ -82,6 +82,7 @@ option(WITH_DLT_LOG_LEVEL_APP_CONFIG "Set to ON to enable default log levels bas
 
 set(DLT_IPC "FIFO" CACHE STRING "UNIX_SOCKET,FIFO")
 set(DLT_USER "genivi" CACHE STRING "Set user for process not run as root")
+set(DLT_QNX_SLOG_ADAPTER_WAIT_BUFFER_TIMEOUT_MS "100" CACHE STRING "Timeout in milliseconds to wait before messages are dropped when input buffer is full")
 
 option(WITH_DLT_PKGCONFIG     "Set to ON to generate pkgconfig .pc files"                                        ON)
 option(WITH_DLT_CXX11_EXT     "Set to ON to build C++11 extensions"                                              OFF)
@@ -142,6 +143,7 @@ include_directories(
 add_definitions(-D_GNU_SOURCE)
 add_definitions(-DDLT_WRITEV_TIMEOUT_SEC=${DLT_WRITEV_TIMEOUT_SEC})
 add_definitions(-DDLT_WRITEV_TIMEOUT_USEC=${DLT_WRITEV_TIMEOUT_USEC})
+add_definitions(-DDLT_QNX_SLOG_ADAPTER_WAIT_BUFFER_TIMEOUT_MS=${DLT_QNX_SLOG_ADAPTER_WAIT_BUFFER_TIMEOUT_MS})
 
 if(NOT DLT_IPC STREQUAL "UNIX_SOCKET" AND NOT DLT_IPC STREQUAL "FIFO")
     message(FATAL_ERROR "${DLT_IPC} is not a valid value for DLT_IPC")
@@ -180,8 +182,8 @@ if(WITH_DLT_USE_IPv6)
     add_definitions(-DDLT_USE_IPv6)
 endif()
 
-if(WITH_DLT_QNX_SYSTEM AND NOT "${CMAKE_C_COMPILER}" MATCHES "nto-qnx|qcc")
-    message(FATAL_ERROR "Can only compile for QNX with a QNX compiler.")
+if(WITH_DLT_QNX_SYSTEM AND NOT "${CMAKE_C_COMPILER}" MATCHES "nto-qnx|qcc|ntoaarch64-gcc|ntox86_64-gcc")
+    message(FATAL_ERROR "Can only compile for QNX with a QNX compiler, but found '${CMAKE_C_COMPILER}'.")
 endif()
 
 if (WITH_DLT_FILE_LOGGING_SYSLOG_FALLBACK)

doc/dlt_build_options.md

@@ -59,6 +59,7 @@ WITH\_DLT\_DBUS                   | OFF            | Set to ON to build src/dbus
 Option | Value | Comment
 :--- | :--- | :---
 WITH\_DLT\_QNX\_SYSTEM            | OFF            | Set to ON to build QNX system binary dlt-qnx-system
+DLT\_QNX\_SLOG\_ADAPTER\_WAIT\_BUFFER\_TIMEOUT\_MS | 100 | Maximum time in milliseconds to wait for buffer space in dlt before messages from the slog will be discarded.
 
 ## Documentation Options
 

src/dlt-qnx-system/dlt-qnx-slogger2-adapter.cpp

@@ -28,9 +28,13 @@
 #include <sys/slog2.h>
 #include <sys/json.h>
 #include <slog2_parse.h>
+#include <thread>
+#include <set>
 
 #include "dlt-qnx-system.h"
 #include "dlt_cpp_extension.hpp"
+using std::chrono_literals::operator""ms;
+using std::chrono_literals::operator""s;
 
 /* Teach dlt about json_decoder_error_t */
 template<>
@@ -42,6 +46,7 @@ inline int32_t logToDlt(DltContextData &log, const json_decoder_error_t &value)
 extern DltContext dltQnxSystem;
 
 static DltContext dltQnxSlogger2Context;
+static std::set<std::string> dltWarnedMissingMappings;
 
 extern DltQnxSystemThreads g_threads;
 
@@ -121,14 +126,49 @@ static DltContext *dlt_context_from_slog2file(const char *file_name) {
 
     auto search = g_slog2file.find(name);
     if (search == g_slog2file.end()) {
-        DLT_LOG_CXX(dltQnxSlogger2Context, DLT_LOG_VERBOSE,
-                "slog2 filename not found in mapping: ", name.c_str());
+        // Only warn once about missing mapping.
+        auto it = dltWarnedMissingMappings.find(name);
+        if (it == dltWarnedMissingMappings.end()) {
+            dltWarnedMissingMappings.insert(name);
+            DLT_LOG_CXX(dltQnxSlogger2Context, DLT_LOG_INFO,
+                        "slog2 filename not found in mapping: ", name.c_str());
+        }
+
         return &dltQnxSlogger2Context;
     } else {
         return search->second;
     }
 }
 
+template <class time, class period>
+static void wait_for_buffer_space(const double max_usage_threshold,
+                                  const std::chrono::duration<time, period> max_wait_time) {
+    int total_size = 0;
+    int used_size = 0;
+    double used_percent = 100.0;
+    bool timeout = false;
+    const auto end_time = std::chrono::steady_clock::now() + max_wait_time;
+
+    do {
+        dlt_user_check_buffer(&total_size, &used_size);
+        used_percent = static_cast<double>(used_size) / total_size;
+        if (used_percent < max_usage_threshold) {
+            break;
+        }
+
+        dlt_user_log_resend_buffer();
+
+        std::this_thread::sleep_for(10ms);
+        timeout = std::chrono::steady_clock::now() < end_time;
+    } while (!timeout);
+
+    if (timeout) {
+        DLT_LOG(dltQnxSystem, DLT_LOG_ERROR,
+                DLT_STRING("failed to get enough buffer space"));
+
+    }
+}
+
 /**
  *  Function which is invoked by slog2_parse_all()
  *  See slog2_parse_all api docs on qnx.com for details
@@ -177,6 +217,8 @@ static int sloggerinfo_callback(slog2_packet_info_t *info, void *payload, void *
     DltContextData log_local; /* Used in DLT_* macros, do not rename */
     DltContext *ctxt = dlt_context_from_slog2file(info->file_name);
 
+    wait_for_buffer_space(0.8, std::chrono::milliseconds(DLT_QNX_SLOG_ADAPTER_WAIT_BUFFER_TIMEOUT_MS));
+
     int ret;
     ret = dlt_user_log_write_start(ctxt, &log_local, loglevel);