Ergonomics Profile

src/hotspot/share/gc/shared/gcConfig.cpp

@@ -96,18 +96,41 @@ void GCConfig::fail_if_non_included_gc_is_selected() {
 }
 
 void GCConfig::select_gc_ergonomically() {
-  if (os::is_server_class_machine()) {
+  if (strcmp(ErgonomicsProfile, "shared") == 0) {
+    if (os::is_server_class_machine()) {
 #if INCLUDE_G1GC
-    FLAG_SET_ERGO_IF_DEFAULT(UseG1GC, true);
+      FLAG_SET_ERGO_IF_DEFAULT(UseG1GC, true);
 #elif INCLUDE_PARALLELGC
-    FLAG_SET_ERGO_IF_DEFAULT(UseParallelGC, true);
+      FLAG_SET_ERGO_IF_DEFAULT(UseParallelGC, true);
 #elif INCLUDE_SERIALGC
-    FLAG_SET_ERGO_IF_DEFAULT(UseSerialGC, true);
+      FLAG_SET_ERGO_IF_DEFAULT(UseSerialGC, true);
 #endif
-  } else {
+    } else {
+#if INCLUDE_SERIALGC
+      FLAG_SET_ERGO_IF_DEFAULT(UseSerialGC, true);
+#endif
+    }
+  } else if (strcmp(ErgonomicsProfile, "dedicated") == 0) {
+    julong phys_mem = os::physical_memory();
+    if (os::active_processor_count() <= 1) {
 #if INCLUDE_SERIALGC
-    FLAG_SET_ERGO_IF_DEFAULT(UseSerialGC, true);
+      FLAG_SET_ERGO_IF_DEFAULT(UseSerialGC, true);
+#endif
+    } else if (phys_mem >= 16*G){
+#if INCLUDE_ZGC
+      FLAG_SET_ERGO_IF_DEFAULT(UseZGC, true);
 #endif
+    } else if (phys_mem > 2048*M){
+#if INCLUDE_G1GC
+      FLAG_SET_ERGO_IF_DEFAULT(UseG1GC, true);
+#endif
+    } else { 
+#if INCLUDE_PARALLELGC
+      FLAG_SET_ERGO_IF_DEFAULT(UseParallelGC, true);
+#endif
+    }
+  } else {
+    ShouldNotReachHere();
   }
 }
 

src/hotspot/share/gc/shared/gc_globals.hpp

@@ -131,6 +131,12 @@
   product(bool, UseShenandoahGC, false,                                     \
           "Use the Shenandoah garbage collector")                           \
                                                                             \
+  product(ccstr, ErgonomicsProfile, "shared",                               \
+          "Ergonomics profile to use. "                                     \
+          "Options include \"shared\" for when the JVM is running "         \
+          "in a shared environment and \"dedicated\" for when the "         \
+          "JVM is running on a system with dedicated resources")            \
+                                                                            \
   /* notice: the max range value here is INT_MAX not UINT_MAX  */           \
   /* to protect from overflows                                 */           \
   product(uint, ParallelGCThreads, 0,                                       \

src/hotspot/share/runtime/arguments.cpp

@@ -70,6 +70,9 @@
 #if INCLUDE_JFR
 #include "jfr/jfr.hpp"
 #endif
+#ifdef LINUX
+#include "osContainer_linux.hpp"
+#endif
 
 #include <limits>
 
@@ -1514,6 +1517,22 @@ jint Arguments::set_ergonomics_flags() {
   return JNI_OK;
 }
 
+void Arguments::set_ergonomics_profile() {
+  if (FLAG_IS_DEFAULT(ErgonomicsProfile)){
+
+#ifdef LINUX
+    if (OSContainer::is_containerized()){
+      FLAG_SET_ERGO(ErgonomicsProfile, "dedicated");
+    }
+#endif //LINUX
+
+  } else {
+    if (strcmp(ErgonomicsProfile, "shared") != 0 && strcmp(ErgonomicsProfile, "dedicated") != 0) {
+      vm_exit_during_initialization(err_msg("Unsupported ErgonomicsProfile: %s", ErgonomicsProfile));
+    }
+  }
+}
+
 size_t Arguments::limit_heap_by_allocatable_memory(size_t limit) {
   size_t max_allocatable;
   size_t result = limit;
@@ -1561,6 +1580,22 @@ void Arguments::set_heap_size() {
                                        : (julong)MaxRAM;
   }
 
+   // Update default heap size for dedicated ergonomics profile
+  if (strcmp(ErgonomicsProfile, "dedicated") == 0) {
+    FLAG_SET_DEFAULT(MinRAMPercentage, 25.0);
+    FLAG_SET_DEFAULT(InitialRAMPercentage, 50.0);
+    if (phys_mem >= 16*G){
+      FLAG_SET_DEFAULT(MaxRAMPercentage, 90.0); 
+    } else if (phys_mem >= 6*G){
+      FLAG_SET_DEFAULT(MaxRAMPercentage, 85.0);
+    } else if (phys_mem >= 4*G){
+      FLAG_SET_DEFAULT(MaxRAMPercentage, 80.0);
+    } else if (phys_mem >= 0.5*G){
+      FLAG_SET_DEFAULT(MaxRAMPercentage, 75.0);
+    } else { 
+      FLAG_SET_DEFAULT(MaxRAMPercentage, 50.0);
+    }
+  }
 
   // Convert deprecated flags
   if (FLAG_IS_DEFAULT(MaxRAMPercentage) &&
@@ -3981,6 +4016,8 @@ jint Arguments::apply_ergo() {
   jint result = set_ergonomics_flags();
   if (result != JNI_OK) return result;
 
+  set_ergonomics_profile();
+
   // Set heap size based on available physical memory
   set_heap_size();
 

src/hotspot/share/runtime/arguments.hpp

@@ -260,6 +260,7 @@ class Arguments : AllStatic {
   static bool _ClipInlining;
 
   // GC ergonomics
+  static void set_ergonomics_profile();
   static void set_conservative_max_heap_alignment();
   static void set_use_compressed_oops();
   static void set_use_compressed_klass_ptrs();