8241678: Remove PerfData sampling via StatSampler

src/hotspot/os/aix/os_aix.cpp

@@ -58,7 +58,6 @@
 #include "runtime/perfMemory.hpp"
 #include "runtime/safefetch.hpp"
 #include "runtime/sharedRuntime.hpp"
-#include "runtime/statSampler.hpp"
 #include "runtime/threadCritical.hpp"
 #include "runtime/threads.hpp"
 #include "runtime/timer.hpp"

src/hotspot/os/bsd/os_bsd.cpp

@@ -53,7 +53,6 @@
 #include "runtime/perfMemory.hpp"
 #include "runtime/semaphore.hpp"
 #include "runtime/sharedRuntime.hpp"
-#include "runtime/statSampler.hpp"
 #include "runtime/stubRoutines.hpp"
 #include "runtime/threadCritical.hpp"
 #include "runtime/threads.hpp"

src/hotspot/os/linux/os_linux.cpp

@@ -56,7 +56,6 @@
 #include "runtime/osThread.hpp"
 #include "runtime/perfMemory.hpp"
 #include "runtime/sharedRuntime.hpp"
-#include "runtime/statSampler.hpp"
 #include "runtime/stubRoutines.hpp"
 #include "runtime/threadCritical.hpp"
 #include "runtime/threads.hpp"

src/hotspot/os/windows/os_windows.cpp

@@ -60,7 +60,6 @@
 #include "runtime/safepointMechanism.hpp"
 #include "runtime/semaphore.inline.hpp"
 #include "runtime/sharedRuntime.hpp"
-#include "runtime/statSampler.hpp"
 #include "runtime/stubRoutines.hpp"
 #include "runtime/suspendedThreadTask.hpp"
 #include "runtime/threadCritical.hpp"

src/hotspot/share/gc/parallel/spaceCounters.cpp

@@ -33,8 +33,7 @@
 
 SpaceCounters::SpaceCounters(const char* name, int ordinal, size_t max_size,
                              MutableSpace* m, GenerationCounters* gc)
-  : _last_used_in_bytes(0), _object_space(m)
-{
+    : _object_space(m) {
   if (UsePerfData) {
     EXCEPTION_MARK;
     ResourceMark rm;
@@ -60,7 +59,7 @@ SpaceCounters::SpaceCounters(const char* name, int ordinal, size_t max_size,
 
     cname = PerfDataManager::counter_name(_name_space, "used");
     _used = PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes,
-                                             new UsedHelper(this),
+                                             _object_space->used_in_bytes(),
                                              CHECK);
 
     cname = PerfDataManager::counter_name(_name_space, "initCapacity");
@@ -74,21 +73,5 @@ SpaceCounters::~SpaceCounters() {
 }
 
 void SpaceCounters::update_used() {
-  size_t new_used = _object_space->used_in_bytes();
-  Atomic::store(&_last_used_in_bytes, new_used);
-  _used->set_value(new_used);
-}
-
-jlong SpaceCounters::UsedHelper::take_sample() {
-  // Sampling may occur during GC, possibly while GC is updating the space.
-  // The space can be in an inconsistent state during such an update.  We
-  // don't want to block sampling for the duration of a GC.  Instead, skip
-  // sampling in that case, using the last recorded value.
-  assert(!Heap_lock->owned_by_self(), "precondition");
-  if (Heap_lock->try_lock()) {
-    size_t new_used = _counters->_object_space->used_in_bytes();
-    Atomic::store(&_counters->_last_used_in_bytes, new_used);
-    Heap_lock->unlock();
-  }
-  return Atomic::load(&_counters->_last_used_in_bytes);
+  _used->set_value(_object_space->used_in_bytes());
 }

src/hotspot/share/gc/parallel/spaceCounters.hpp

@@ -39,7 +39,6 @@ class SpaceCounters: public CHeapObj<mtGC> {
  private:
   PerfVariable*      _capacity;
   PerfVariable*      _used;
-  volatile size_t    _last_used_in_bytes;
 
   // Constant PerfData types don't need to retain a reference.
   // However, it's a good idea to document them here.
@@ -48,8 +47,6 @@ class SpaceCounters: public CHeapObj<mtGC> {
   MutableSpace*     _object_space;
   char*             _name_space;
 
-  class UsedHelper;
-
  public:
 
   SpaceCounters(const char* name, int ordinal, size_t max_size,
@@ -71,14 +68,4 @@ class SpaceCounters: public CHeapObj<mtGC> {
   const char* name_space() const        { return _name_space; }
 };
 
-class SpaceCounters::UsedHelper: public PerfLongSampleHelper {
- private:
-  SpaceCounters* _counters;
-
- public:
-  UsedHelper(SpaceCounters* counters) : _counters(counters) { }
-
-  jlong take_sample() override;
-};
-
 #endif // SHARE_GC_PARALLEL_SPACECOUNTERS_HPP

src/hotspot/share/gc/serial/cSpaceCounters.cpp

@@ -28,8 +28,7 @@
 
 CSpaceCounters::CSpaceCounters(const char* name, int ordinal, size_t max_size,
                                ContiguousSpace* s, GenerationCounters* gc)
-  : _last_used_in_bytes(0), _space(s)
-{
+    : _space(s) {
   if (UsePerfData) {
     EXCEPTION_MARK;
     ResourceMark rm;
@@ -57,7 +56,7 @@ CSpaceCounters::CSpaceCounters(const char* name, int ordinal, size_t max_size,
 
     cname = PerfDataManager::counter_name(_name_space, "used");
     _used = PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes,
-                                             new UsedHelper(this),
+                                             _space->used(),
                                              CHECK);
 
     cname = PerfDataManager::counter_name(_name_space, "initCapacity");
@@ -75,26 +74,10 @@ void CSpaceCounters::update_capacity() {
 }
 
 void CSpaceCounters::update_used() {
-  size_t new_used = _space->used();
-  Atomic::store(&_last_used_in_bytes, new_used);
-  _used->set_value(new_used);
+  _used->set_value(_space->used());
 }
 
 void CSpaceCounters::update_all() {
   update_used();
   update_capacity();
 }
-
-jlong CSpaceCounters::UsedHelper::take_sample(){
-  // Sampling may occur during GC, possibly while GC is updating the space.
-  // The space can be in an inconsistent state during such an update.  We
-  // don't want to block sampling for the duration of a GC.  Instead, skip
-  // sampling in that case, using the last recorded value.
-  assert(!Heap_lock->owned_by_self(), "precondition");
-  if (Heap_lock->try_lock()) {
-    size_t new_used = _counters->_space->used();
-    Atomic::store(&_counters->_last_used_in_bytes, new_used);
-    Heap_lock->unlock();
-  }
-  return Atomic::load(&_counters->_last_used_in_bytes);
-}

src/hotspot/share/gc/serial/cSpaceCounters.hpp

@@ -39,7 +39,6 @@ class CSpaceCounters: public CHeapObj<mtGC> {
   PerfVariable*      _capacity;
   PerfVariable*      _used;
   PerfVariable*      _max_capacity;
-  volatile size_t    _last_used_in_bytes;
 
   // Constant PerfData types don't need to retain a reference.
   // However, it's a good idea to document them here.
@@ -48,8 +47,6 @@ class CSpaceCounters: public CHeapObj<mtGC> {
   ContiguousSpace*     _space;
   char*                _name_space;
 
-  class UsedHelper;
-
  public:
 
   CSpaceCounters(const char* name, int ordinal, size_t max_size,
@@ -64,14 +61,4 @@ class CSpaceCounters: public CHeapObj<mtGC> {
   const char* name_space() const        { return _name_space; }
 };
 
-class CSpaceCounters::UsedHelper : public PerfLongSampleHelper {
- private:
-  CSpaceCounters* _counters;
-
- public:
-  UsedHelper(CSpaceCounters* counters) : _counters(counters) { }
-
-  jlong take_sample() override;
-};
-
 #endif // SHARE_GC_SERIAL_CSPACECOUNTERS_HPP

src/hotspot/share/runtime/arguments.cpp

@@ -532,6 +532,7 @@ static SpecialFlag const special_jvm_flags[] = {
 
   // -------------- Obsolete Flags - sorted by expired_in --------------
 
+  { "PerfDataSamplingInterval",     JDK_Version::undefined(), JDK_Version::jdk(25), JDK_Version::jdk(26) },
   { "MetaspaceReclaimPolicy",       JDK_Version::undefined(), JDK_Version::jdk(21), JDK_Version::undefined() },
   { "ZGenerational",                JDK_Version::jdk(23), JDK_Version::jdk(24), JDK_Version::undefined() },
   { "ZMarkStackSpaceLimit",         JDK_Version::undefined(), JDK_Version::jdk(25), JDK_Version::undefined() },

src/hotspot/share/runtime/globals.hpp

@@ -1720,11 +1720,6 @@ const int ObjectAlignmentInBytes = 8;
           "The string %p in the file name (if present) "                    \
           "will be replaced by pid")                                        \
                                                                             \
-  product(int, PerfDataSamplingInterval, 50,                                \
-          "Data sampling interval (in milliseconds)")                       \
-          range(PeriodicTask::min_interval, max_jint)                       \
-          constraint(PerfDataSamplingIntervalFunc, AfterErgo)               \
-                                                                            \
   product(bool, PerfDisableSharedMem, false,                                \
           "Store performance data in standard memory")                      \
                                                                             \

src/hotspot/share/runtime/java.cpp

@@ -70,7 +70,6 @@
 #include "runtime/java.hpp"
 #include "runtime/javaThread.hpp"
 #include "runtime/sharedRuntime.hpp"
-#include "runtime/statSampler.hpp"
 #include "runtime/stubRoutines.hpp"
 #include "runtime/task.hpp"
 #include "runtime/threads.hpp"
@@ -463,10 +462,6 @@ void before_exit(JavaThread* thread, bool halt) {
   // PeriodicTasks to reduce the likelihood of races.
   WatcherThread::stop();
 
-  // shut down the StatSampler task
-  StatSampler::disengage();
-  StatSampler::destroy();
-
   NativeHeapTrimmer::cleanup();
 
   // Stop concurrent GC threads