[GR-50665] Make the snippet template cache global instead of per snippet.

PullRequest: graal/21168

Author: thomaswue

compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/nodes/spi/DelegatingReplacements.java

@@ -25,6 +25,7 @@
 package jdk.graal.compiler.nodes.spi;
 
 import java.util.BitSet;
+import java.util.Map;
 
 import jdk.graal.compiler.api.replacements.SnippetTemplateCache;
 import jdk.graal.compiler.bytecode.BytecodeProvider;
@@ -38,6 +39,7 @@
 import jdk.graal.compiler.nodes.graphbuilderconf.GraphBuilderPlugin;
 import jdk.graal.compiler.nodes.graphbuilderconf.InvocationPlugin;
 import jdk.graal.compiler.options.OptionValues;
+import jdk.graal.compiler.replacements.SnippetTemplate;
 import jdk.vm.ci.meta.JavaKind;
 import jdk.vm.ci.meta.ResolvedJavaMethod;
 
@@ -137,4 +139,9 @@ public <T extends SnippetTemplateCache> T getSnippetTemplateCache(Class<T> templ
     public JavaKind getWordKind() {
         return delegate.getWordKind();
     }
+
+    @Override
+    public Map<SnippetTemplate.CacheKey, SnippetTemplate> getTemplatesCache() {
+        return delegate.getTemplatesCache();
+    }
 }

compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/nodes/spi/Replacements.java

@@ -25,6 +25,7 @@
 package jdk.graal.compiler.nodes.spi;
 
 import java.util.BitSet;
+import java.util.Map;
 
 import jdk.graal.compiler.api.replacements.Snippet;
 import jdk.graal.compiler.api.replacements.SnippetTemplateCache;
@@ -39,6 +40,7 @@
 import jdk.graal.compiler.nodes.graphbuilderconf.GraphBuilderPlugin;
 import jdk.graal.compiler.nodes.graphbuilderconf.InvocationPlugin;
 import jdk.graal.compiler.options.OptionValues;
+import jdk.graal.compiler.replacements.SnippetTemplate;
 import jdk.vm.ci.meta.JavaKind;
 import jdk.vm.ci.meta.ResolvedJavaMethod;
 
@@ -55,6 +57,12 @@ public interface Replacements extends GeneratedPluginInjectionProvider {
      */
     GraphBuilderConfiguration.Plugins getGraphBuilderPlugins();
 
+    /**
+     * Least recently used cache for snippet templates. When a new element is added to this map, it
+     * evicts the least recently used element in case of full capacity.
+     */
+    Map<SnippetTemplate.CacheKey, SnippetTemplate> getTemplatesCache();
+
     /**
      * Gets the plugin type that intrinsifies calls to {@code method}.
      */

compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/replacements/ReplacementsImpl.java

@@ -33,6 +33,8 @@
 import static jdk.graal.compiler.phases.common.DeadCodeEliminationPhase.Optionality.Required;
 
 import java.util.BitSet;
+import java.util.Collections;
+import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -111,6 +113,12 @@ public void setProviders(Providers providers) {
     public final TargetDescription target;
     protected GraphBuilderConfiguration.Plugins graphBuilderPlugins;
     private final DebugHandlersFactory debugHandlersFactory;
+    private final Map<SnippetTemplate.CacheKey, SnippetTemplate> templatesCache;
+
+    @Override
+    public Map<SnippetTemplate.CacheKey, SnippetTemplate> getTemplatesCache() {
+        return templatesCache;
+    }
 
     /**
      * The preprocessed replacement graphs. This is keyed by a pair of a method and options because
@@ -242,6 +250,7 @@ public ReplacementsImpl(DebugHandlersFactory debugHandlersFactory, Providers pro
         this.snippetTemplateCache = EconomicMap.create(Equivalence.DEFAULT);
         this.defaultBytecodeProvider = bytecodeProvider;
         this.debugHandlersFactory = debugHandlersFactory;
+        this.templatesCache = Collections.synchronizedMap(new SnippetTemplate.LRUCache<>());
     }
 
     private static final TimerKey SnippetPreparationTime = DebugContext.timer("SnippetPreparationTime");

compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/replacements/SnippetTemplate.java

@@ -45,7 +45,6 @@
 import java.util.Iterator;
 import java.util.LinkedHashMap;
 import java.util.List;
-import java.util.Map;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.Predicate;
 
@@ -799,7 +798,7 @@ public ValueNode findLength(FindLengthMode mode, ConstantReflectionProvider cons
         }
     }
 
-    static class CacheKey {
+    public static class CacheKey {
 
         private final ResolvedJavaMethod method;
         private final Object[] values;
@@ -857,9 +856,6 @@ public int hashCode() {
     public static class Options {
         @Option(help = "Use a LRU cache for snippet templates.")//
         public static final OptionKey<Boolean> UseSnippetTemplateCache = new OptionKey<>(true);
-
-        @Option(help = "")//
-        public static final OptionKey<Integer> MaxTemplatesPerSnippet = new OptionKey<>(50);
     }
 
     /**
@@ -869,20 +865,13 @@ public abstract static class AbstractTemplates implements SnippetTemplateCache {
 
         protected final OptionValues options;
         protected final SnippetReflectionProvider snippetReflection;
-        private final Map<CacheKey, SnippetTemplate> templates;
 
         private final boolean shouldTrackNodeSourcePosition;
 
         protected AbstractTemplates(OptionValues options, Providers providers) {
             this.options = options;
             this.snippetReflection = providers.getSnippetReflection();
             this.shouldTrackNodeSourcePosition = providers.getCodeCache() != null && providers.getCodeCache().shouldDebugNonSafepoints();
-            if (Options.UseSnippetTemplateCache.getValue(options)) {
-                int size = Options.MaxTemplatesPerSnippet.getValue(options);
-                this.templates = Collections.synchronizedMap(new LRUCache<>(size, size));
-            } else {
-                this.templates = null;
-            }
         }
 
         public static ResolvedJavaMethod findMethod(MetaAccessProvider metaAccess, Class<?> declaringClass, String methodName) {
@@ -981,7 +970,7 @@ protected SnippetInfo snippet(Providers providers,
         public SnippetTemplate template(CoreProviders context, ValueNode replacee, final Arguments args) {
             StructuredGraph graph = replacee.graph();
             DebugContext outer = graph.getDebug();
-            SnippetTemplate template = Options.UseSnippetTemplateCache.getValue(options) && args.cacheable ? templates.get(args.cacheKey) : null;
+            SnippetTemplate template = Options.UseSnippetTemplateCache.getValue(options) && args.cacheable ? context.getReplacements().getTemplatesCache().get(args.cacheKey) : null;
             if (template == null || (graph.trackNodeSourcePosition() && !template.snippet.trackNodeSourcePosition())) {
                 try (DebugContext debug = context.getReplacements().openSnippetDebugContext("SnippetTemplate_", args.cacheKey.method, outer, options)) {
                     try (DebugCloseable a = SnippetTemplateCreationTime.start(outer);
@@ -1002,7 +991,7 @@ public SnippetTemplate template(CoreProviders context, ValueNode replacee, final
                                         createMidTierPreLoweringPhases(),
                                         createMidTierPostLoweringPhases());
                         if (Options.UseSnippetTemplateCache.getValue(snippetOptions) && args.cacheable) {
-                            templates.put(args.cacheKey, template);
+                            context.getReplacements().getTemplatesCache().put(args.cacheKey, template);
                         }
                         if (outer.areMetricsEnabled()) {
                             DebugContext.counter("SnippetTemplateNodeCount[%#s]", args).add(outer, template.nodes.size());
@@ -1037,11 +1026,21 @@ protected PhaseSuite<CoreProviders> createMidTierPostLoweringPhases() {
 
     public static final class LRUCache<K, V> extends LinkedHashMap<K, V> {
         private static final long serialVersionUID = 1L;
+
+        /**
+         * Maximum capacity of the least-recently used snippet template cache. A higher number
+         * increases the total amount of memory used for snippet templates and a lower number
+         * increases the cache misses and thus decreases compilation speed. At a value of 64, the
+         * estimated misses are at 2% of lookups, at 80, they are at 1% of lookups, and at 100, they
+         * are at 0.5% of lookups.
+         */
+        public static final int SNIPPET_CACHE_CAPACITY = 64;
+
         private final int maxCacheSize;
 
-        public LRUCache(int initialCapacity, int maxCacheSize) {
-            super(initialCapacity, 0.75F, true);
-            this.maxCacheSize = maxCacheSize;
+        public LRUCache() {
+            super(SNIPPET_CACHE_CAPACITY, 0.75F, true);
+            this.maxCacheSize = SNIPPET_CACHE_CAPACITY;
         }
 
         @Override

compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/util/ObjectCopier.java

@@ -285,12 +285,11 @@ static final class HashMapBuiltin extends Builtin {
 
         HashMapBuiltin() {
             super(HashMap.class, IdentityHashMap.class, LinkedHashMap.class, SnippetTemplate.LRUCache.class);
-            int size = SnippetTemplate.Options.MaxTemplatesPerSnippet.getDefaultValue();
             factories = Map.of(
                             HashMap.class, HashMap::new,
                             IdentityHashMap.class, IdentityHashMap::new,
                             LinkedHashMap.class, LinkedHashMap::new,
-                            SnippetTemplate.LRUCache.class, () -> new SnippetTemplate.LRUCache<>(size, size));
+                            SnippetTemplate.LRUCache.class, SnippetTemplate.LRUCache::new);
         }
 
         @Override

sdk/src/org.graalvm.collections/src/org/graalvm/collections/EconomicMapImpl.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2017, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * The Universal Permissive License (UPL), Version 1.0

sdk/src/org.graalvm.collections/src/org/graalvm/collections/EconomicMapWrap.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2021, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * The Universal Permissive License (UPL), Version 1.0

sdk/src/org.graalvm.collections/src/org/graalvm/collections/EmptyMap.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * The Universal Permissive License (UPL), Version 1.0

sdk/src/org.graalvm.collections/src/org/graalvm/collections/UnmodifiableEconomicMap.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2017, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * The Universal Permissive License (UPL), Version 1.0