Add vsync_interval option

src/xenia/gpu/gpu_flags.cc

@@ -20,6 +20,9 @@ DEFINE_path(
 
 DEFINE_bool(vsync, true, "Enable VSYNC.", "GPU");
 
+DEFINE_uint64(vsync_interval, 16,
+              "VSYNC interval. Value is frametime in milliseconds.", "GPU");
+
 DEFINE_bool(
     gpu_allow_invalid_fetch_constants, false,
     "Allow texture and vertex fetch constants with invalid type - generally "

src/xenia/gpu/gpu_flags.h

@@ -18,6 +18,8 @@ DECLARE_path(dump_shaders);
 
 DECLARE_bool(vsync);
 
+DECLARE_uint64(vsync_interval);
+
 DECLARE_bool(gpu_allow_invalid_fetch_constants);
 
 DECLARE_bool(half_pixel_offset);

src/xenia/gpu/graphics_system.cc

@@ -7,6 +7,8 @@
  ******************************************************************************
  */
 
+#include <algorithm>
+
 #include "xenia/gpu/graphics_system.h"
 
 #include <cstdint>
@@ -98,7 +100,8 @@ X_STATUS GraphicsSystem::Setup(cpu::Processor* processor,
   vsync_worker_running_ = true;
   vsync_worker_thread_ = kernel::object_ref<kernel::XHostThread>(
       new kernel::XHostThread(kernel_state_, 128 * 1024, 0, [this]() {
-        uint64_t vsync_duration = cvars::vsync ? 16 : 1;
+        uint64_t vsync_duration =
+            cvars::vsync ? std::max<uint64_t>(5, cvars::vsync_interval) : 1;
         uint64_t last_frame_time = Clock::QueryGuestTickCount();
         while (vsync_worker_running_) {
           uint64_t current_time = Clock::QueryGuestTickCount();