vk: remove unnecessary flush and gc (#7207)

filament/backend/src/vulkan/VulkanDriver.cpp

@@ -290,9 +290,11 @@ void VulkanDriver::setPresentationTime(int64_t monotonic_clock_ns) {
 }
 
 void VulkanDriver::endFrame(uint32_t frameId) {
-    if (mCommands->flush()) {
-        collectGarbage();
-    }
+    FVK_SYSTRACE_CONTEXT();
+    FVK_SYSTRACE_START("endframe");
+    mCommands->flush();
+    collectGarbage();
+    FVK_SYSTRACE_END();
 }
 
 void VulkanDriver::flush(int) {
@@ -1370,10 +1372,6 @@ void VulkanDriver::commit(Handle<HwSwapChain> sch) {
 
     VulkanSwapChain* swapChain = mResourceAllocator.handle_cast<VulkanSwapChain*>(sch);
 
-    if (mCommands->flush()) {
-        collectGarbage();
-    }
-
     // Present the backbuffer after the most recent command buffer submission has finished.
     swapChain->present();
     FVK_SYSTRACE_END();

filament/backend/src/vulkan/VulkanSwapChain.cpp

@@ -88,8 +88,8 @@ void VulkanSwapChain::present() {
                 .layerCount = 1,
         };
         mColors[mCurrentSwapIndex]->transitionLayout(cmdbuf, subresources, VulkanLayout::PRESENT);
-        mCommands->flush();
     }
+    mCommands->flush();
     VkSemaphore const finishedDrawing = mCommands->acquireFinishedSignal();
     VkResult const result = mPlatform->present(swapChain, mCurrentSwapIndex, finishedDrawing);
     ASSERT_POSTCONDITION(result == VK_SUCCESS || result == VK_SUBOPTIMAL_KHR