Set the thread pool count to 4 for vts3 tests.
Thread priority is from
https://source.corp.google.com/android/frameworks/native/services/surfaceflinger/main_surfaceflinger.cpp;rcl=e9cdd276a89d512137f22650da0c45ee4b28bd66;l=97

Test: atest VtsHalGraphicsComposer3_TargetTest
BUG: 207005096
Change-Id: Ic37b454c4ae3990fd8cb38fcdd50747083b2528c
diff --git a/graphics/composer/aidl/android/hardware/graphics/composer3/vts/functional/VtsHalGraphicsComposer3_TargetTest.cpp b/graphics/composer/aidl/android/hardware/graphics/composer3/vts/functional/VtsHalGraphicsComposer3_TargetTest.cpp
index 7a20a53..0d71b68 100644
--- a/graphics/composer/aidl/android/hardware/graphics/composer3/vts/functional/VtsHalGraphicsComposer3_TargetTest.cpp
+++ b/graphics/composer/aidl/android/hardware/graphics/composer3/vts/functional/VtsHalGraphicsComposer3_TargetTest.cpp
@@ -1950,5 +1950,41 @@
         ALOGE("Failed to stop init.svc.surfaceflinger");
         return -1;
     }
+
+    android::ProcessState::self()->setThreadPoolMaxThreadCount(4);
+
+    // The binder threadpool we start will inherit sched policy and priority
+    // of (this) creating thread. We want the binder thread pool to have
+    // SCHED_FIFO policy and priority 1 (lowest RT priority)
+    // Once the pool is created we reset this thread's priority back to
+    // original.
+    // This thread policy is based on what we do in the SurfaceFlinger while starting
+    // the thread pool and we need to replicate that for the VTS tests.
+    int newPriority = 0;
+    int origPolicy = sched_getscheduler(0);
+    struct sched_param origSchedParam;
+
+    int errorInPriorityModification = sched_getparam(0, &origSchedParam);
+    if (errorInPriorityModification == 0) {
+        int policy = SCHED_FIFO;
+        newPriority = sched_get_priority_min(policy);
+
+        struct sched_param param;
+        param.sched_priority = newPriority;
+
+        errorInPriorityModification = sched_setscheduler(0, policy, &param);
+    }
+
+    // start the thread pool
+    android::ProcessState::self()->startThreadPool();
+
+    // Reset current thread's policy and priority
+    if (errorInPriorityModification == 0) {
+        errorInPriorityModification = sched_setscheduler(0, origPolicy, &origSchedParam);
+    } else {
+        ALOGE("Failed to set VtsHalGraphicsComposer3_TargetTest binder threadpool priority to "
+              "SCHED_FIFO");
+    }
+
     return RUN_ALL_TESTS();
 }