Add log for GPU semaphore (#32)

add log from semaphore

Signed-off-by: Firestarman <[email protected]>

sql-plugin/src/main/scala/com/nvidia/spark/rapids/GpuSemaphore.scala

@@ -162,7 +162,7 @@ object GpuSemaphore {
  * this is considered to be okay as there are other mechanisms in place, and it should be rather
  * rare.
  */
-private final class SemaphoreTaskInfo() extends Logging {
+private final class SemaphoreTaskInfo(taskAttemptId: Long) extends Logging {
   /**
    * This holds threads that are not on the GPU yet. Most of the time they are
    * blocked waiting for the semaphore to let them on, but it may hold one
@@ -251,6 +251,7 @@ private final class SemaphoreTaskInfo() extends Logging {
           // We cannot be in a synchronized block and wait on the semaphore
           // so we have to release it and grab it again afterwards.
           semaphore.acquire(numPermits)
+          logInfo(s"==> Task $taskAttemptId acquiring GPU with $numPermits permits")
           synchronized {
             // We now own the semaphore so we need to wake up all of the other tasks that are
             // waiting.
@@ -304,6 +305,7 @@ private final class SemaphoreTaskInfo() extends Logging {
     activeThreads.remove(t)
     if (hasSemaphore) {
       semaphore.release(numPermits)
+      logInfo(s"==> Task $taskAttemptId releasing GPU with $numPermits permits")
       hasSemaphore = false
     }
     // It should be impossible for the current thread to be blocked when releasing the semaphore
@@ -327,7 +329,7 @@ private final class GpuSemaphore() extends Logging {
     val taskAttemptId = context.taskAttemptId()
     val taskInfo = tasks.computeIfAbsent(taskAttemptId, _ => {
       onTaskCompletion(context, completeTask)
-      new SemaphoreTaskInfo()
+      new SemaphoreTaskInfo(taskAttemptId)
     })
     if (taskInfo.tryAcquire(semaphore)) {
       GpuDeviceManager.initializeFromTask()
@@ -351,7 +353,7 @@ private final class GpuSemaphore() extends Logging {
       val taskAttemptId = context.taskAttemptId()
       val taskInfo = tasks.computeIfAbsent(taskAttemptId, _ => {
         onTaskCompletion(context, completeTask)
-        new SemaphoreTaskInfo()
+        new SemaphoreTaskInfo(taskAttemptId)
       })
       taskInfo.blockUntilReady(semaphore)
       GpuDeviceManager.initializeFromTask()