core: Add a configuration setting for use_multi_core.

src/core/core.cpp

@@ -126,6 +126,21 @@ PerfStats::Results System::GetAndResetPerfStats() {
     return perf_stats.GetAndResetStats(CoreTiming::GetGlobalTimeUs());
 }
 
+const std::shared_ptr<Kernel::Scheduler>& System::Scheduler(size_t core_index) {
+    if (!Settings::values.use_multi_core) {
+        // Always use Core 0 scheduler when multicore is disabled
+        return cpu_cores[0]->Scheduler();
+    }
+
+    ASSERT(core_index < NUM_CPU_CORES);
+    return cpu_cores[core_index]->Scheduler();
+}
+
+ARM_Interface& System::ArmInterface(size_t core_index) {
+    ASSERT(core_index < NUM_CPU_CORES);
+    return cpu_cores[core_index]->ArmInterface();
+}
+
 System::ResultStatus System::Init(EmuWindow* emu_window, u32 system_mode) {
     NGLOG_DEBUG(HW_Memory, "initialized OK");
 
@@ -154,9 +169,12 @@ System::ResultStatus System::Init(EmuWindow* emu_window, u32 system_mode) {
     // Create threads for CPU cores 1-3, and build thread_to_cpu map
     // CPU core 0 is run on the main thread
     thread_to_cpu[std::this_thread::get_id()] = cpu_cores[0];
-    for (size_t index = 0; index < cpu_core_threads.size(); ++index) {
-        cpu_core_threads[index] = std::make_unique<std::thread>(RunCpuCore, cpu_cores[index + 1]);
-        thread_to_cpu[cpu_core_threads[index]->get_id()] = cpu_cores[index + 1];
+    if (Settings::values.use_multi_core) {
+        for (size_t index = 0; index < cpu_core_threads.size(); ++index) {
+            cpu_core_threads[index] =
+                std::make_unique<std::thread>(RunCpuCore, cpu_cores[index + 1]);
+            thread_to_cpu[cpu_core_threads[index]->get_id()] = cpu_cores[index + 1];
+        }
     }
 
     NGLOG_DEBUG(Core, "Initialized OK");
@@ -190,9 +208,11 @@ void System::Shutdown() {
 
     // Close all CPU/threading state
     cpu_barrier->NotifyEnd();
-    for (auto& thread : cpu_core_threads) {
-        thread->join();
-        thread.reset();
+    if (Settings::values.use_multi_core) {
+        for (auto& thread : cpu_core_threads) {
+            thread->join();
+            thread.reset();
+        }
     }
     thread_to_cpu.clear();
     for (auto& cpu_core : cpu_cores) {

src/core/core.h

@@ -112,10 +112,7 @@ public:
         return CurrentCpuCore().ArmInterface();
     }
 
-    ARM_Interface& ArmInterface(size_t core_index) {
-        ASSERT(core_index < NUM_CPU_CORES);
-        return cpu_cores[core_index]->ArmInterface();
-    }
+    ARM_Interface& ArmInterface(size_t core_index);
 
     Tegra::GPU& GPU() {
         return *gpu_core;
@@ -125,10 +122,7 @@ public:
         return *CurrentCpuCore().Scheduler();
     }
 
-    const std::shared_ptr<Kernel::Scheduler>& Scheduler(size_t core_index) {
-        ASSERT(core_index < NUM_CPU_CORES);
-        return cpu_cores[core_index]->Scheduler();
-    }
+    const std::shared_ptr<Kernel::Scheduler>& Scheduler(size_t core_index);
 
     Kernel::SharedPtr<Kernel::Process>& CurrentProcess() {
         return current_process;

src/core/core_cpu.cpp

@@ -26,9 +26,12 @@ void CpuBarrier::NotifyEnd() {
 }
 
 bool CpuBarrier::Rendezvous() {
-    if (end) {
-        return false;
-    } else {
+    if (!Settings::values.use_multi_core) {
+        // Meaningless when running in single-core mode
+        return true;
+    }
+
+    if (!end) {
         std::unique_lock<std::mutex> lock(mutex);
 
         --cores_waiting;
@@ -41,6 +44,8 @@ bool CpuBarrier::Rendezvous() {
         condition.wait(lock);
         return true;
     }
+
+    return false;
 }
 
 Cpu::Cpu(std::shared_ptr<CpuBarrier> cpu_barrier, size_t core_index)

src/core/settings.h

@@ -121,6 +121,7 @@ struct Values {
 
     // Core
     bool use_cpu_jit;
+    bool use_multi_core;
 
     // Data Storage
     bool use_virtual_sd;

src/core/telemetry_session.cpp

@@ -155,6 +155,8 @@ TelemetrySession::TelemetrySession() {
 
     // Log user configuration information
     AddField(Telemetry::FieldType::UserConfig, "Core_UseCpuJit", Settings::values.use_cpu_jit);
+    AddField(Telemetry::FieldType::UserConfig, "Core_UseMultiCore",
+             Settings::values.use_multi_core);
     AddField(Telemetry::FieldType::UserConfig, "Renderer_ResolutionFactor",
              Settings::values.resolution_factor);
     AddField(Telemetry::FieldType::UserConfig, "Renderer_ToggleFramelimit",