src/Pure/System/java_statistics.scala

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/Pure/System/java_statistics.scala	Thu Sep 10 21:14:50 2020 +0200
@@ -0,0 +1,45 @@
+/*  Title:      Pure/System/java_statistics.scala
+    Author:     Makarius
+
+Java runtime statistics.
+*/
+
+package isabelle
+
+
+object Java_Statistics
+{
+  /* memory status */
+
+  sealed case class Memory_Status(heap_size: Long, heap_free: Long)
+  {
+    def heap_used: Long = (heap_size - heap_free) max 0
+    def heap_used_fraction: Double =
+      if (heap_size == 0) 0.0 else heap_used.toDouble / heap_size
+  }
+
+  def memory_status(): Memory_Status =
+  {
+    val heap_size = Runtime.getRuntime.totalMemory()
+    val heap_used = heap_size - Runtime.getRuntime.freeMemory()
+    Memory_Status(heap_size, heap_used)
+  }
+
+
+  /* JVM statistics */
+
+  def jvm_statistics(): Properties.T =
+  {
+    val status = memory_status()
+    val threads = Thread.activeCount()
+    val workers = Isabelle_Thread.pool.getPoolSize
+    val workers_active = Isabelle_Thread.pool.getActiveCount
+
+    List(
+      "java_heap_size" -> status.heap_size.toString,
+      "java_heap_used" -> status.heap_used.toString,
+      "java_threads_total" -> threads.toString,
+      "java_workers_total" -> workers.toString,
+      "java_workers_active" -> workers_active.toString)
+  }
+}