Fix render thread priority for allocateBuffers

Increase the prio for the thread allocateBuffer runs on
 so we don't cause the main RT prio thread wait as long
 during frame draws.

Bug: 399701430
Test: app launch test
Flag: com.android.graphics.libgui.flags.allocate_buffer_priority

Change-Id: Ic56697866f1f58c6c5575909da9e1ecd95a3cb06

2 files changed, 22 insertions, 4 deletions

diff --git a/libs/gui/BLASTBufferQueue.cpp b/libs/gui/BLASTBufferQueue.cpp
index fa971426a7..1aae13c1f4 100644
--- a/libs/gui/BLASTBufferQueue.cpp
+++ b/libs/gui/BLASTBufferQueue.cpp
@@ -937,15 +937,22 @@ public:
           : Surface(igbp, controlledByApp, scHandle), mBbq(bbq) {}
 
     void allocateBuffers() override {
+        ATRACE_CALL();
         uint32_t reqWidth = mReqWidth ? mReqWidth : mUserWidth;
         uint32_t reqHeight = mReqHeight ? mReqHeight : mUserHeight;
         auto gbp = getIGraphicBufferProducer();
-        std::thread ([reqWidth, reqHeight, gbp=getIGraphicBufferProducer(),
-                      reqFormat=mReqFormat, reqUsage=mReqUsage] () {
+        std::thread allocateThread([reqWidth, reqHeight, gbp = getIGraphicBufferProducer(),
+                                    reqFormat = mReqFormat, reqUsage = mReqUsage]() {
+            if (com_android_graphics_libgui_flags_allocate_buffer_priority()) {
+                androidSetThreadName("allocateBuffers");
+                pid_t tid = gettid();
+                androidSetThreadPriority(tid, ANDROID_PRIORITY_DISPLAY);
+            }
+
             gbp->allocateBuffers(reqWidth, reqHeight,
                                  reqFormat, reqUsage);
-
-        }).detach();
+        });
+        allocateThread.detach();
     }
 
     status_t setFrameRate(float frameRate, int8_t compatibility,
diff --git a/libs/gui/libgui_flags.aconfig b/libs/gui/libgui_flags.aconfig
index 534f05e987..2c3222dd82 100644
--- a/libs/gui/libgui_flags.aconfig
+++ b/libs/gui/libgui_flags.aconfig
@@ -142,3 +142,14 @@ flag {
   bug: "340934031"
   is_fixed_read_only: true
 } # wb_media_migration
+
+flag {
+  name: "allocate_buffer_priority"
+  namespace: "wear_system_health"
+  description: "Boost priority for buffer allocation"
+  bug: "399701430"
+  metadata {
+    purpose: PURPOSE_BUGFIX
+  }
+  is_fixed_read_only: true
+} # allocate_buffer_priority