diff a/src/hotspot/share/gc/shenandoah/shenandoahHeapRegionCounters.cpp b/src/hotspot/share/gc/shenandoah/shenandoahHeapRegionCounters.cpp
--- a/src/hotspot/share/gc/shenandoah/shenandoahHeapRegionCounters.cpp
+++ b/src/hotspot/share/gc/shenandoah/shenandoahHeapRegionCounters.cpp
@@ -1,7 +1,8 @@
 /*
  * Copyright (c) 2016, 2020, Red Hat, Inc. All rights reserved.
+ * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
@@ -21,17 +22,21 @@
  * questions.
  *
  */
 
 #include "precompiled.hpp"
+
+#include "gc/shenandoah/shenandoahGeneration.hpp"
 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
 #include "gc/shenandoah/shenandoahHeapRegion.inline.hpp"
 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp"
 #include "gc/shenandoah/shenandoahHeapRegionCounters.hpp"
+#include "logging/logStream.hpp"
 #include "memory/resourceArea.hpp"
 #include "runtime/atomic.hpp"
 #include "runtime/perfData.inline.hpp"
+#include "utilities/defaultStream.hpp"
 
 ShenandoahHeapRegionCounters::ShenandoahHeapRegionCounters() :
   _last_sample_millis(0)
 {
   if (UsePerfData && ShenandoahRegionSampling) {
@@ -47,66 +52,151 @@
     _timestamp = PerfDataManager::create_long_variable(SUN_GC, cname, PerfData::U_None, CHECK);
 
     cname = PerfDataManager::counter_name(_name_space, "max_regions");
     PerfDataManager::create_constant(SUN_GC, cname, PerfData::U_None, num_regions, CHECK);
 
+    cname = PerfDataManager::counter_name(_name_space, "protocol_version");
+    PerfDataManager::create_constant(SUN_GC, cname, PerfData::U_None, VERSION_NUMBER, CHECK);
+
     cname = PerfDataManager::counter_name(_name_space, "region_size");
     PerfDataManager::create_constant(SUN_GC, cname, PerfData::U_None, ShenandoahHeapRegion::region_size_bytes() >> 10, CHECK);
 
     cname = PerfDataManager::counter_name(_name_space, "status");
     _status = PerfDataManager::create_long_variable(SUN_GC, cname,
                                                     PerfData::U_None, CHECK);
 
     _regions_data = NEW_C_HEAP_ARRAY(PerfVariable*, num_regions, mtGC);
+    // Initializing performance data resources for each region
     for (uint i = 0; i < num_regions; i++) {
       const char* reg_name = PerfDataManager::name_space(_name_space, "region", i);
       const char* data_name = PerfDataManager::counter_name(reg_name, "data");
       const char* ns = PerfDataManager::ns_to_string(SUN_GC);
       const char* fullname = PerfDataManager::counter_name(ns, data_name);
       assert(!PerfDataManager::exists(fullname), "must not exist");
-      _regions_data[i] = PerfDataManager::create_long_variable(SUN_GC, data_name,
-                                                               PerfData::U_None, CHECK);
+      _regions_data[i] = PerfDataManager::create_long_variable(SUN_GC, data_name, PerfData::U_None, CHECK);
     }
   }
 }
 
 ShenandoahHeapRegionCounters::~ShenandoahHeapRegionCounters() {
   if (_name_space != nullptr) FREE_C_HEAP_ARRAY(char, _name_space);
 }
 
+void ShenandoahHeapRegionCounters::write_snapshot(PerfLongVariable** regions,
+                                             PerfLongVariable* ts,
+                                             PerfLongVariable* status,
+                                             size_t num_regions,
+                                             size_t region_size, size_t protocol_version) {
+  LogTarget(Trace, gc, region) lt;
+  if (lt.is_enabled()) {
+    ResourceMark rm;
+    LogStream ls(lt);
+
+    ls.print_cr(JLONG_FORMAT " " JLONG_FORMAT " " SIZE_FORMAT " " SIZE_FORMAT " " SIZE_FORMAT,
+            ts->get_value(), status->get_value(), num_regions, region_size, protocol_version);
+    if (num_regions > 0) {
+      ls.print(JLONG_FORMAT, regions[0]->get_value());
+    }
+    for (uint i = 1; i < num_regions; ++i) {
+      ls.print(" " JLONG_FORMAT, regions[i]->get_value());
+    }
+    ls.cr();
+  }
+}
+
 void ShenandoahHeapRegionCounters::update() {
   if (ShenandoahRegionSampling) {
     jlong current = nanos_to_millis(os::javaTimeNanos());
     jlong last = _last_sample_millis;
-    if (current - last > ShenandoahRegionSamplingRate &&
-            Atomic::cmpxchg(&_last_sample_millis, last, current) == last) {
+    if (current - last > ShenandoahRegionSamplingRate && Atomic::cmpxchg(&_last_sample_millis, last, current) == last) {
 
       ShenandoahHeap* heap = ShenandoahHeap::heap();
-      jlong status = 0;
-      if (heap->is_concurrent_mark_in_progress())      status |= 1 << 0;
-      if (heap->is_evacuation_in_progress())           status |= 1 << 1;
-      if (heap->is_update_refs_in_progress())          status |= 1 << 2;
-      _status->set_value(status);
-
+      _status->set_value(encode_heap_status(heap));
       _timestamp->set_value(os::elapsed_counter());
 
-      size_t num_regions = heap->num_regions();
-
       {
         ShenandoahHeapLocker locker(heap->lock());
         size_t rs = ShenandoahHeapRegion::region_size_bytes();
+        size_t num_regions = heap->num_regions();
         for (uint i = 0; i < num_regions; i++) {
           ShenandoahHeapRegion* r = heap->get_region(i);
           jlong data = 0;
           data |= ((100 * r->used() / rs)                & PERCENT_MASK) << USED_SHIFT;
           data |= ((100 * r->get_live_data_bytes() / rs) & PERCENT_MASK) << LIVE_SHIFT;
           data |= ((100 * r->get_tlab_allocs() / rs)     & PERCENT_MASK) << TLAB_SHIFT;
           data |= ((100 * r->get_gclab_allocs() / rs)    & PERCENT_MASK) << GCLAB_SHIFT;
+          data |= ((100 * r->get_plab_allocs() / rs)     & PERCENT_MASK) << PLAB_SHIFT;
           data |= ((100 * r->get_shared_allocs() / rs)   & PERCENT_MASK) << SHARED_SHIFT;
+
+          data |= (r->age() & AGE_MASK) << AGE_SHIFT;
+          data |= (r->affiliation() & AFFILIATION_MASK) << AFFILIATION_SHIFT;
           data |= (r->state_ordinal() & STATUS_MASK) << STATUS_SHIFT;
           _regions_data[i]->set_value(data);
         }
+
+        // If logging enabled, dump current region snapshot to log file
+        write_snapshot(_regions_data, _timestamp, _status, num_regions, rs >> 10, VERSION_NUMBER);
       }
+    }
+  }
+}
 
+static int encode_phase(ShenandoahHeap* heap) {
+  if (heap->is_evacuation_in_progress() || heap->is_full_gc_move_in_progress()) {
+    return 2;
+  }
+  if (heap->is_update_refs_in_progress() || heap->is_full_gc_move_in_progress()) {
+    return 3;
+  }
+  if (heap->is_concurrent_mark_in_progress() || heap->is_full_gc_in_progress()) {
+    return 1;
+  }
+  assert(heap->is_idle(), "What is it doing?");
+  return 0;
+}
+
+static int get_generation_shift(ShenandoahGeneration* generation) {
+  switch (generation->type()) {
+    case NON_GEN:
+    case GLOBAL:
+      return 0;
+    case OLD:
+      return 2;
+    case YOUNG:
+      return 4;
+    default:
+      ShouldNotReachHere();
+      return -1;
+  }
+}
+
+jlong ShenandoahHeapRegionCounters::encode_heap_status(ShenandoahHeap* heap) {
+
+  if (heap->is_idle() && !heap->is_full_gc_in_progress()) {
+    return 0;
+  }
+
+  jlong status = 0;
+  if (!heap->mode()->is_generational()) {
+    status = encode_phase(heap);
+  } else {
+    int phase = encode_phase(heap);
+    ShenandoahGeneration* generation = heap->active_generation();
+    assert(generation != nullptr, "Expected active generation in this mode.");
+    int shift = get_generation_shift(generation);
+    status |= ((phase & 0x3) << shift);
+    if (heap->is_concurrent_old_mark_in_progress()) {
+      status |= (1 << 2);
     }
+    log_develop_trace(gc)("%s, phase=%u, old_mark=%s, status=" JLONG_FORMAT,
+                          generation->name(), phase, BOOL_TO_STR(heap->is_concurrent_old_mark_in_progress()), status);
   }
+
+  if (heap->is_degenerated_gc_in_progress()) {
+    status |= (1 << 6);
+  }
+  if (heap->is_full_gc_in_progress()) {
+    status |= (1 << 7);
+  }
+
+  return status;
 }
