Requeue some external messages if their queues were full to prevent game lockups (#125)

Author: Mr-Wiseguy

librecomp/src/flash.cpp

@@ -154,7 +154,7 @@ extern "C" void osFlashWriteBuffer_recomp(uint8_t * rdram, recomp_context * ctx)
     }
 
     // Send the message indicating write completion
-    osSendMesg(PASS_RDRAM mq, 0, OS_MESG_NOBLOCK);
+    ultramodern::enqueue_external_message(mq, 0, false, true);
 
     ctx->r2 = 0;
 }
@@ -193,7 +193,7 @@ extern "C" void osFlashReadArray_recomp(uint8_t * rdram, recomp_context * ctx) {
     save_read(PASS_RDRAM dramAddr, offset, count);
 
     // Send the message indicating read completion
-    osSendMesg(PASS_RDRAM mq, 0, OS_MESG_NOBLOCK);
+    ultramodern::enqueue_external_message(mq, 0, false, true);
 
     ctx->r2 = 0;
 }

librecomp/src/pi.cpp

@@ -275,7 +275,7 @@ void do_dma(RDRAM_ARG PTR(OSMesgQueue) mq, gpr rdram_address, uint32_t physical_
             recomp::do_rom_read(rdram, rdram_address, physical_addr, size);
 
             // Send a message to the mq to indicate that the transfer completed
-            osSendMesg(rdram, mq, 0, OS_MESG_NOBLOCK);
+            ultramodern::enqueue_external_message(mq, 0, false, true);
         } else if (physical_addr >= recomp::sram_base) {
             if (!recomp::sram_allowed()) {
                 ultramodern::error_handling::message_box("Attempted to use SRAM saving with other save type");
@@ -285,7 +285,7 @@ void do_dma(RDRAM_ARG PTR(OSMesgQueue) mq, gpr rdram_address, uint32_t physical_
             save_read(rdram, rdram_address, physical_addr - recomp::sram_base, size);
 
             // Send a message to the mq to indicate that the transfer completed
-            osSendMesg(rdram, mq, 0, OS_MESG_NOBLOCK);
+            ultramodern::enqueue_external_message(mq, 0, false, true);
         } else {
             fprintf(stderr, "[WARN] PI DMA read from unknown region, phys address 0x%08X\n", physical_addr);
         }
@@ -302,7 +302,7 @@ void do_dma(RDRAM_ARG PTR(OSMesgQueue) mq, gpr rdram_address, uint32_t physical_
             save_write(rdram, rdram_address, physical_addr - recomp::sram_base, size);
 
             // Send a message to the mq to indicate that the transfer completed
-            osSendMesg(rdram, mq, 0, OS_MESG_NOBLOCK);
+            ultramodern::enqueue_external_message(mq, 0, false, true);
         } else {
             fprintf(stderr, "[WARN] PI DMA write to unknown region, phys address 0x%08X\n", physical_addr);
         }

ultramodern/include/ultramodern/ultramodern.hpp

@@ -52,6 +52,7 @@ bool thread_queue_empty(RDRAM_ARG PTR(PTR(OSThread)) queue);
 PTR(OSThread) thread_queue_peek(RDRAM_ARG PTR(PTR(OSThread)) queue);
 
 // Message queues.
+void enqueue_external_message(PTR(OSMesgQueue) mq, OSMesg msg, bool jam, bool requeue_if_blocked);
 void wait_for_external_message(RDRAM_ARG1);
 void wait_for_external_message_timed(RDRAM_ARG1, u32 millis);
 
@@ -77,7 +78,7 @@ PTR(OSThread) this_thread();
 void set_main_thread();
 bool is_game_thread();
 void submit_rsp_task(RDRAM_ARG PTR(OSTask) task);
-void send_si_message(RDRAM_ARG1);
+void send_si_message();
 uint32_t get_speed_multiplier();
 
 // Time

ultramodern/src/events.cpp

@@ -226,21 +226,19 @@ void vi_thread_func() {
         if (ultramodern::is_game_started()) {
             remaining_retraces--;
 
-            uint8_t* rdram = events_context.rdram;
             std::lock_guard lock{ events_context.message_mutex };
             ViState* cur_state = events_context.vi.get_cur_state();
             if (remaining_retraces == 0) {
                 if (cur_state->mq != NULLPTR) {
-                    if (osSendMesg(PASS_RDRAM cur_state->mq, cur_state->msg, OS_MESG_NOBLOCK) == -1) {
-                        //printf("Game skipped a VI frame!\n");
-                    }
+                    // Send a message to the VI queue, and do not set it to be requeued if the queue was full.
+                    // The worst case scenario is that the game misses a VI message and has to wait a little longer for the next. 
+                    ultramodern::enqueue_external_message(cur_state->mq, cur_state->msg, false, false);
                 }
                 remaining_retraces = cur_state->retrace_count;
             }
             if (events_context.ai.mq != NULLPTR) {
-                if (osSendMesg(PASS_RDRAM events_context.ai.mq, events_context.ai.msg, OS_MESG_NOBLOCK) == -1) {
-                    //printf("Game skipped a AI frame!\n");
-                }
+                // Send a message to the VI queue, and do not set it to be requeued if the queue was full for the same reason as the VI message above.
+                ultramodern::enqueue_external_message(events_context.ai.mq, events_context.ai.msg, false, false);
             }
         }
 
@@ -253,13 +251,13 @@ void vi_thread_func() {
 void sp_complete() {
     uint8_t* rdram = events_context.rdram;
     std::lock_guard lock{ events_context.message_mutex };
-    osSendMesg(PASS_RDRAM events_context.sp.mq, events_context.sp.msg, OS_MESG_NOBLOCK);
+    ultramodern::enqueue_external_message(events_context.sp.mq, events_context.sp.msg, false, true);
 }
 
 void dp_complete() {
     uint8_t* rdram = events_context.rdram;
     std::lock_guard lock{ events_context.message_mutex };
-    osSendMesg(PASS_RDRAM events_context.dp.mq, events_context.dp.msg, OS_MESG_NOBLOCK);
+    ultramodern::enqueue_external_message(events_context.dp.mq, events_context.dp.msg, false, true);
 }
 
 void task_thread_func(uint8_t* rdram, moodycamel::LightweightSemaphore* thread_ready) {
@@ -559,8 +557,8 @@ void ultramodern::submit_rsp_task(RDRAM_ARG PTR(OSTask) task_) {
     }
 }
 
-void ultramodern::send_si_message(RDRAM_ARG1) {
-    osSendMesg(PASS_RDRAM events_context.si.mq, events_context.si.msg, OS_MESG_NOBLOCK);
+void ultramodern::send_si_message() {
+    ultramodern::enqueue_external_message(events_context.si.mq, events_context.si.msg, false, true);
 }
 
 void ultramodern::init_events(RDRAM_ARG ultramodern::renderer::WindowHandle window_handle) {

ultramodern/src/input.cpp

@@ -98,7 +98,7 @@ extern "C" s32 osContReset(RDRAM_ARG PTR(OSMesgQueue) mq, PTR(OSContStatus) data
 }
 
 extern "C" s32 osContStartQuery(RDRAM_ARG PTR(OSMesgQueue) mq) {
-    ultramodern::send_si_message(PASS_RDRAM1);
+    ultramodern::send_si_message();
 
     return 0;
 }
@@ -109,7 +109,7 @@ extern "C" s32 osContStartReadData(RDRAM_ARG PTR(OSMesgQueue) mq) {
     }
     update_poll_time();
 
-    ultramodern::send_si_message(rdram);
+    ultramodern::send_si_message();
 
     return 0;
 }

ultramodern/src/mesgqueue.cpp

@@ -9,33 +9,44 @@ struct QueuedMessage {
     PTR(OSMesgQueue) mq;
     OSMesg mesg;
     bool jam;
+    bool requeue_if_blocked;
 };
 
 static moodycamel::BlockingConcurrentQueue<QueuedMessage> external_messages {};
 
-void enqueue_external_message(PTR(OSMesgQueue) mq, OSMesg msg, bool jam) {
-    external_messages.enqueue({mq, msg, jam});
+void ultramodern::enqueue_external_message(PTR(OSMesgQueue) mq, OSMesg msg, bool jam, bool requeue_if_blocked) {
+    external_messages.enqueue({mq, msg, jam, requeue_if_blocked});
 }
 
 bool do_send(RDRAM_ARG PTR(OSMesgQueue) mq_, OSMesg msg, bool jam, bool block);
 
 void dequeue_external_messages(RDRAM_ARG1) {
     QueuedMessage to_send;
+    std::vector<QueuedMessage> requeued_messages{};
     while (external_messages.try_dequeue(to_send)) {
-        do_send(PASS_RDRAM to_send.mq, to_send.mesg, to_send.jam, false);
+        if (!do_send(PASS_RDRAM to_send.mq, to_send.mesg, to_send.jam, false) && to_send.requeue_if_blocked) {
+            requeued_messages.push_back(to_send);
+        }
+    }
+    for (QueuedMessage& cur_mesg : requeued_messages) {
+        external_messages.enqueue(cur_mesg);
     }
 }
 
 void ultramodern::wait_for_external_message(RDRAM_ARG1) {
     QueuedMessage to_send;
     external_messages.wait_dequeue(to_send);
-    do_send(PASS_RDRAM to_send.mq, to_send.mesg, to_send.jam, false);
+    if (!do_send(PASS_RDRAM to_send.mq, to_send.mesg, to_send.jam, false) && to_send.requeue_if_blocked) {
+        external_messages.enqueue(to_send);
+    }
 }
 
-void ultramodern::wait_for_external_message_timed(RDRAM_ARG1, u32 millis) {
+void ultramodern::wait_for_external_message_timed(RDRAM_ARG u32 millis) {
     QueuedMessage to_send;
     if (external_messages.wait_dequeue_timed(to_send, std::chrono::milliseconds{millis})) {
-        do_send(PASS_RDRAM to_send.mq, to_send.mesg, to_send.jam, false);
+        if (!do_send(PASS_RDRAM to_send.mq, to_send.mesg, to_send.jam, false) && to_send.requeue_if_blocked) {
+            external_messages.enqueue(to_send);
+        }
     }
 }
 
@@ -138,7 +149,7 @@ extern "C" s32 osSendMesg(RDRAM_ARG PTR(OSMesgQueue) mq_, OSMesg msg, s32 flags)
 
     // Don't directly send to the message queue if this isn't a game thread to avoid contention.
     if (!ultramodern::is_game_thread()) {
-        enqueue_external_message(mq_, msg, jam);
+        ultramodern::enqueue_external_message(mq_, msg, jam, false);
         return 0;
     }
 
@@ -160,7 +171,7 @@ extern "C" s32 osJamMesg(RDRAM_ARG PTR(OSMesgQueue) mq_, OSMesg msg, s32 flags)
 
     // Don't directly send to the message queue if this isn't a game thread to avoid contention.
     if (!ultramodern::is_game_thread()) {
-        enqueue_external_message(mq_, msg, jam);
+        ultramodern::enqueue_external_message(mq_, msg, jam, false);
         return 0;
     }
 

ultramodern/src/timer.cpp

@@ -130,7 +130,7 @@ void timer_thread(RDRAM_ARG1) {
         }
         else {
             // Waiting for the timer completed, so send the timer's message to its message queue
-            osSendMesg(PASS_RDRAM cur_timer->mq, cur_timer->msg, OS_MESG_NOBLOCK);
+            ultramodern::enqueue_external_message(cur_timer->mq, cur_timer->msg, false, true);
             // If the timer has a specified interval then reload it with that value
             if (cur_timer->interval != 0) {
                 cur_timer->timestamp = cur_timer->interval + time_now();