From 1c751a064538c9e80b49fd0270db034ed0dcf11f Mon Sep 17 00:00:00 2001
From: wuyan <[email protected]>
Date: Thu, 5 Aug 2021 17:29:26 +0800
Subject: [PATCH 2/8] 8257145: Performance regression with -XX:-ResizePLAB
 after JDK-8079555

Summary: <gc>: backport of JDK-8264640, Performance regression with -XX:-ResizePLAB after JDK-8079555
LLT: NA
Patch Type: backport
Bug url: https://bugs.openjdk.java.net/browse/JDK-8257145
---
 src/hotspot/share/gc/cms/parNewGeneration.cpp        | 2 +-
 src/hotspot/share/gc/g1/g1EvacStats.cpp              | 5 +++--
 src/hotspot/share/gc/g1/g1EvacStats.hpp              | 2 +-
 src/hotspot/share/gc/shared/plab.cpp                 | 3 +++
 src/hotspot/share/gc/shared/plab.hpp                 | 6 ++++--
 test/hotspot/jtreg/gc/g1/plab/TestPLABPromotion.java | 2 +-
 6 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/src/hotspot/share/gc/cms/parNewGeneration.cpp b/src/hotspot/share/gc/cms/parNewGeneration.cpp
index 1b95cf52e..b1e8bde61 100644
--- a/src/hotspot/share/gc/cms/parNewGeneration.cpp
+++ b/src/hotspot/share/gc/cms/parNewGeneration.cpp
@@ -627,7 +627,7 @@ ParNewGeneration::ParNewGeneration(ReservedSpace rs, size_t initial_byte_size)
   : DefNewGeneration(rs, initial_byte_size, "PCopy"),
   _overflow_list(NULL),
   _is_alive_closure(this),
-  _plab_stats("Young", YoungPLABSize, PLABWeight)
+  _plab_stats("Young", YoungPLABSize, YoungPLABSize * ParallelGCThreads, PLABWeight)
 {
   NOT_PRODUCT(_overflow_counter = ParGCWorkQueueOverflowInterval;)
   NOT_PRODUCT(_num_par_pushes = 0;)
diff --git a/src/hotspot/share/gc/g1/g1EvacStats.cpp b/src/hotspot/share/gc/g1/g1EvacStats.cpp
index 70c399691..7070e1840 100644
--- a/src/hotspot/share/gc/g1/g1EvacStats.cpp
+++ b/src/hotspot/share/gc/g1/g1EvacStats.cpp
@@ -28,6 +28,7 @@
 #include "gc/shared/gcId.hpp"
 #include "logging/log.hpp"
 #include "memory/allocation.inline.hpp"
+#include "runtime/globals.hpp"
 
 void G1EvacStats::log_plab_allocation() {
   PLABStats::log_plab_allocation();
@@ -89,8 +90,8 @@ size_t G1EvacStats::compute_desired_plab_sz() {
   return cur_plab_sz;
 }
 
-G1EvacStats::G1EvacStats(const char* description, size_t desired_plab_sz_, unsigned wt) :
-  PLABStats(description, desired_plab_sz_, wt),
+G1EvacStats::G1EvacStats(const char* description, size_t default_per_thread_plab_size, unsigned wt) :
+  PLABStats(description, default_per_thread_plab_size, default_per_thread_plab_size * ParallelGCThreads, wt),
   _region_end_waste(0),
   _regions_filled(0),
   _direct_allocated(0),
diff --git a/src/hotspot/share/gc/g1/g1EvacStats.hpp b/src/hotspot/share/gc/g1/g1EvacStats.hpp
index 4ac6fd9f5..0baf2fc20 100644
--- a/src/hotspot/share/gc/g1/g1EvacStats.hpp
+++ b/src/hotspot/share/gc/g1/g1EvacStats.hpp
@@ -56,7 +56,7 @@ class G1EvacStats : public PLABStats {
   virtual size_t compute_desired_plab_sz();
 
  public:
-  G1EvacStats(const char* description, size_t desired_plab_sz_, unsigned wt);
+  G1EvacStats(const char* description, size_t default_per_thread_plab_size, unsigned wt);
 
   ~G1EvacStats();
 
diff --git a/src/hotspot/share/gc/shared/plab.cpp b/src/hotspot/share/gc/shared/plab.cpp
index 29c4cc694..0ad6dda4a 100644
--- a/src/hotspot/share/gc/shared/plab.cpp
+++ b/src/hotspot/share/gc/shared/plab.cpp
@@ -136,6 +136,9 @@ void PLABStats::log_sizing(size_t calculated_words, size_t net_desired_words) {
 
 // Calculates plab size for current number of gc worker threads.
 size_t PLABStats::desired_plab_sz(uint no_of_gc_workers) {
+  if (!ResizePLAB) {
+      return _default_plab_sz;
+  }
   return align_object_size(MIN2(MAX2(min_size(), _desired_net_plab_sz / no_of_gc_workers), max_size()));
 }
 
diff --git a/src/hotspot/share/gc/shared/plab.hpp b/src/hotspot/share/gc/shared/plab.hpp
index 608dce56c..06e9cfef3 100644
--- a/src/hotspot/share/gc/shared/plab.hpp
+++ b/src/hotspot/share/gc/shared/plab.hpp
@@ -151,6 +151,7 @@ class PLABStats : public CHeapObj<mtGC> {
   size_t _wasted;             // of which wasted (internal fragmentation)
   size_t _undo_wasted;        // of which wasted on undo (is not used for calculation of PLAB size)
   size_t _unused;             // Unused in last buffer
+  size_t _default_plab_sz;
   size_t _desired_net_plab_sz;// Output of filter (below), suitably trimmed and quantized
   AdaptiveWeightedAverage
          _filter;             // Integrator with decay
@@ -169,13 +170,14 @@ class PLABStats : public CHeapObj<mtGC> {
   virtual size_t compute_desired_plab_sz();
 
  public:
-  PLABStats(const char* description, size_t desired_net_plab_sz_, unsigned wt) :
+  PLABStats(const char* description, size_t default_per_thread_plab_size, size_t desired_net_plab_sz, unsigned wt) :
     _description(description),
     _allocated(0),
     _wasted(0),
     _undo_wasted(0),
     _unused(0),
-    _desired_net_plab_sz(desired_net_plab_sz_),
+    _default_plab_sz(default_per_thread_plab_size),
+    _desired_net_plab_sz(desired_net_plab_sz),
     _filter(wt)
   { }
 
diff --git a/test/hotspot/jtreg/gc/g1/plab/TestPLABPromotion.java b/test/hotspot/jtreg/gc/g1/plab/TestPLABPromotion.java
index 97f221eeb..6be46e36b 100644
--- a/test/hotspot/jtreg/gc/g1/plab/TestPLABPromotion.java
+++ b/test/hotspot/jtreg/gc/g1/plab/TestPLABPromotion.java
@@ -73,7 +73,7 @@ public class TestPLABPromotion {
     private static final int PLAB_SIZE_HIGH = 65536;
     private static final int OBJECT_SIZE_SMALL = 10;
     private static final int OBJECT_SIZE_MEDIUM = 100;
-    private static final int OBJECT_SIZE_HIGH = 1000;
+    private static final int OBJECT_SIZE_HIGH = 3500;
     private static final int GC_NUM_SMALL = 1;
     private static final int GC_NUM_MEDIUM = 3;
     private static final int GC_NUM_HIGH = 7;
-- 
2.22.0