demo: improve tranmission timing

GetTickCount64 has a documented resolution of 10-16 ms.
Switch code to QueryPerformanceCounter which like has
better resolution.

Windows/app/app.c

@@ -1,7 +1,7 @@
 /*
  * The MIT License (MIT)
  *
- * Copyright (c) 2021-2022 Jean Gressmann <[email protected]>
+ * Copyright (c) 2021-2025 Jean Gressmann <[email protected]>
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -123,3 +123,23 @@ void log_candump(
         fprintf(f, "\n");
     }
 }
+
+static uint64_t s_perf_counter_freq = 1;
+
+void app_init()
+{
+    QueryPerformanceFrequency((LARGE_INTEGER*)&s_perf_counter_freq);
+
+}
+
+uint64_t mono_ticks()
+{
+    uint64_t now;
+    QueryPerformanceCounter((LARGE_INTEGER*)&now);
+    return now;
+}
+
+uint64_t mono_millis()
+{
+    return (mono_ticks() * 1000U) / s_perf_counter_freq;
+}

Windows/app/app.h

@@ -1,7 +1,7 @@
 /*
  * The MIT License (MIT)
  *
- * Copyright (c) 2020-2022 Jean Gressmann <[email protected]>
+ * Copyright (c) 2020-2025 Jean Gressmann <[email protected]>
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -157,6 +157,11 @@ void log_candump(
     uint8_t dlc,
     uint8_t const* data);
 
+uint64_t mono_ticks();
+uint64_t mono_millis();
+
+void app_init();
+
 #ifdef __cplusplus
 } // extern "C"
 #endif

Windows/app/main.c

@@ -248,6 +248,8 @@ int main(int argc, char** argv)
 
     cia_fd_cbt_init_default_real(&ac.nominal_user_constraints, &ac.data_user_constraints);
 
+    app_init();
+
     for (int i = 1; i < argc; ) {
         if (0 == strcmp("-h", argv[i]) ||
             0 == strcmp("--help", argv[i]) ||

Windows/app/shared.cpp

@@ -1,7 +1,7 @@
 /*
  * The MIT License (MIT)
  *
- * Copyright (c) 2020-2023 Jean Gressmann <[email protected]>
+ * Copyright (c) 2020-2025 Jean Gressmann <[email protected]>
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -495,8 +495,11 @@ int run(app_ctx* ac)
     SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_HIGHEST);
 
     while (1) {
-
+        uint64_t const wait_start_time = mono_millis();
         auto r = WaitForMultipleObjects(static_cast<DWORD>(_countof(handles)), handles, FALSE, timeout_ms);
+        uint64_t const now = mono_millis();
+        DWORD const elapsed_ms = (DWORD)(now - wait_start_time);
+
         if (r >= WAIT_OBJECT_0 && r < WAIT_OBJECT_0 + _countof(handles)) {
             auto index = r - WAIT_OBJECT_0;
             auto handle = handles[index];
@@ -522,8 +525,13 @@ int run(app_ctx* ac)
         process_rx(ac);
 
         if (ac->tx_job_count) {
-            timeout_ms = 0xffffffff;
-            ULONGLONG now = GetTickCount64();
+            if (elapsed_ms >= timeout_ms) {
+                timeout_ms = 0xffffffff;
+            }
+            else {
+                timeout_ms -= elapsed_ms;
+            }
+
             bool queued = false;
 
             for (size_t i = 0; i < ac->tx_job_count; ++i) {

Windows/app/single.c

@@ -1,7 +1,7 @@
 /*
  * The MIT License (MIT)
  *
- * Copyright (c) 2020-2023 Jean Gressmann <[email protected]>
+ * Copyright (c) 2020-2025 Jean Gressmann <[email protected]>
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -695,7 +695,11 @@ int run_single(struct app_ctx* ac)
     SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_HIGHEST);
 
     while (1) {
+        uint64_t const wait_start_time = mono_millis();
         error = sc_can_stream_rx(can_state.stream, timeout_ms);
+        uint64_t const now = mono_millis();
+        DWORD const elapsed_ms = (DWORD)(now - wait_start_time);
+
         if (error) {
             if (SC_DLL_ERROR_USER_HANDLE_SIGNALED == error) {
                 break;
@@ -710,8 +714,12 @@ int run_single(struct app_ctx* ac)
         }
 
         if (ac->tx_job_count) {
-            timeout_ms = 0xffffffff;
-            ULONGLONG now = GetTickCount64();
+            if (elapsed_ms >= timeout_ms) {
+                timeout_ms = 0xffffffff;
+            }
+            else {
+                timeout_ms -= elapsed_ms;
+            }
 
             error = sc_can_stream_tx_batch_begin(can_state.stream);
             if (error) {