Add custom EXI buffer management

Exificient's SAXDecoder by default does not free its internal buffer,
and allocates one for each decoder. With version 1.0.4 we have enough
visibility to perform buffer management.

This adds a thread-local buffer, which is reused during parse operation
and retained if it is under 64kB after the operation completes.

Change-Id: Ie2f7c72b1160d389a07c473fda6739b7eb7212cb
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>

diff --git a/netconf/netconf-netty-util/src/main/java/org/opendaylight/netconf/nettyutil/handler/NetconfEXICodec.java b/netconf/netconf-netty-util/src/main/java/org/opendaylight/netconf/nettyutil/handler/NetconfEXICodec.java
index 7c74416e6226059a98ba00c094f9147bbcf26f71..415afe3d0abad056a01a6b6301ec05f972177025 100644 (file)
--- a/netconf/netconf-netty-util/src/main/java/org/opendaylight/netconf/nettyutil/handler/NetconfEXICodec.java
+++ b/netconf/netconf-netty-util/src/main/java/org/opendaylight/netconf/nettyutil/handler/NetconfEXICodec.java
@@ -5,7 +5,6 @@
  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
  * and is available at http://www.eclipse.org/legal/epl-v10.html
  */
-
 package org.opendaylight.netconf.nettyutil.handler;
 
 import static java.util.Objects.requireNonNull;
@@ -17,10 +16,8 @@ import org.opendaylight.netconf.nettyutil.handler.exi.EXIParameters;
 import org.opendaylight.netconf.shaded.exificient.core.EXIFactory;
 import org.opendaylight.netconf.shaded.exificient.core.exceptions.EXIException;
 import org.opendaylight.netconf.shaded.exificient.main.api.sax.SAXEncoder;
-import org.opendaylight.netconf.shaded.exificient.main.api.sax.SAXFactory;
 import org.xml.sax.EntityResolver;
 import org.xml.sax.InputSource;
-import org.xml.sax.XMLReader;
 
 public final class NetconfEXICodec {
     /**
@@ -41,24 +38,23 @@ public final class NetconfEXICodec {
                 }
             });
 
-    private final SAXFactory exiFactory;
+    private final ThreadLocalSAXFactory exiFactory;
 
     private NetconfEXICodec(final EXIFactory exiFactory) {
-        this.exiFactory = new SAXFactory(requireNonNull(exiFactory));
+        this.exiFactory = new ThreadLocalSAXFactory(requireNonNull(exiFactory));
     }
 
     public static NetconfEXICodec forParameters(final EXIParameters parameters) {
         return CODECS.getUnchecked(parameters);
     }
 
-    XMLReader getReader() throws EXIException {
-        final XMLReader reader = exiFactory.createEXIReader();
+    ThreadLocalSAXDecoder getReader() throws EXIException {
+        final ThreadLocalSAXDecoder reader = exiFactory.createEXIReader();
         reader.setEntityResolver(ENTITY_RESOLVER);
         return reader;
     }
 
     SAXEncoder getWriter() throws EXIException {
-        final SAXEncoder writer = exiFactory.createEXIWriter();
-        return writer;
+        return exiFactory.createEXIWriter();
     }
 }

diff --git a/netconf/netconf-netty-util/src/main/java/org/opendaylight/netconf/nettyutil/handler/NetconfEXIToMessageDecoder.java b/netconf/netconf-netty-util/src/main/java/org/opendaylight/netconf/nettyutil/handler/NetconfEXIToMessageDecoder.java
index 4ea4202adc6a0f5e50f0bcdda641e339bb61068c..0f85d18c16964be7b72b3d94fcb504f937e1a99d 100644 (file)
--- a/netconf/netconf-netty-util/src/main/java/org/opendaylight/netconf/nettyutil/handler/NetconfEXIToMessageDecoder.java
+++ b/netconf/netconf-netty-util/src/main/java/org/opendaylight/netconf/nettyutil/handler/NetconfEXIToMessageDecoder.java
@@ -32,7 +32,6 @@ import org.slf4j.LoggerFactory;
 import org.w3c.dom.Document;
 import org.xml.sax.InputSource;
 import org.xml.sax.SAXException;
-import org.xml.sax.XMLReader;
 
 public final class NetconfEXIToMessageDecoder extends ByteToMessageDecoder {
 
@@ -54,10 +53,10 @@ public final class NetconfEXIToMessageDecoder extends ByteToMessageDecoder {
      * which means that {@link #decode(ChannelHandlerContext, ByteBuf, List)}
      * cannot be invoked concurrently. Hence we can reuse the reader.
      */
-    private final XMLReader reader;
+    private final ThreadLocalSAXDecoder reader;
     private final DocumentBuilder documentBuilder;
 
-    private NetconfEXIToMessageDecoder(final XMLReader reader) {
+    private NetconfEXIToMessageDecoder(final ThreadLocalSAXDecoder reader) {
         this.reader = requireNonNull(reader);
         this.documentBuilder = UntrustedXML.newDocumentBuilder();
     }

diff --git a/netconf/netconf-netty-util/src/main/java/org/opendaylight/netconf/nettyutil/handler/ThreadLocalSAXDecoder.java b/netconf/netconf-netty-util/src/main/java/org/opendaylight/netconf/nettyutil/handler/ThreadLocalSAXDecoder.java
new file mode 100644 (file)
index 0000000..bc97b62
--- /dev/null
+++ b/netconf/netconf-netty-util/src/main/java/org/opendaylight/netconf/nettyutil/handler/ThreadLocalSAXDecoder.java
@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2019 Pantheon Technologies, s.r.o. and others.  All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.opendaylight.netconf.nettyutil.handler;
+
+import java.io.IOException;
+import org.opendaylight.netconf.shaded.exificient.core.EXIFactory;
+import org.opendaylight.netconf.shaded.exificient.core.exceptions.EXIException;
+import org.opendaylight.netconf.shaded.exificient.main.api.sax.SAXDecoder;
+import org.xml.sax.InputSource;
+import org.xml.sax.SAXException;
+
+/**
+ * Utility SAXDecoder, which reuses a thread-local buffer during parse operations.
+ */
+final class ThreadLocalSAXDecoder extends SAXDecoder {
+    // Note these limits are number of chars, i.e. 2 bytes
+    private static final int INITIAL_SIZE = 4096;
+    private static final int CACHE_MAX_SIZE = 32768;
+    private static final ThreadLocal<char[]> CBUFFER_CACHE = ThreadLocal.withInitial(() -> new char[INITIAL_SIZE]);
+
+    ThreadLocalSAXDecoder(final EXIFactory noOptionsFactory) throws EXIException {
+        super(noOptionsFactory, null);
+    }
+
+    @Override
+    public void parse(final InputSource source) throws IOException, SAXException {
+        cbuffer = CBUFFER_CACHE.get();
+        final int startSize = cbuffer.length;
+        try {
+            super.parse(source);
+        } finally {
+            char[] toCache = cbuffer;
+            cbuffer = null;
+            if (toCache.length > CACHE_MAX_SIZE && startSize < CACHE_MAX_SIZE) {
+                // The buffer grew to large for caching, but make sure we enlarge our cached buffer to prevent
+                // some amount of reallocations in future.
+                toCache = new char[CACHE_MAX_SIZE];
+            }
+            CBUFFER_CACHE.set(toCache);
+        }
+    }
+}

diff --git a/netconf/netconf-netty-util/src/main/java/org/opendaylight/netconf/nettyutil/handler/ThreadLocalSAXFactory.java b/netconf/netconf-netty-util/src/main/java/org/opendaylight/netconf/nettyutil/handler/ThreadLocalSAXFactory.java
new file mode 100644 (file)
index 0000000..821dce8
--- /dev/null
+++ b/netconf/netconf-netty-util/src/main/java/org/opendaylight/netconf/nettyutil/handler/ThreadLocalSAXFactory.java
@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) 2019 Pantheon Technologies, s.r.o. and others.  All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.opendaylight.netconf.nettyutil.handler;
+
+import org.opendaylight.netconf.shaded.exificient.core.EXIFactory;
+import org.opendaylight.netconf.shaded.exificient.core.exceptions.EXIException;
+import org.opendaylight.netconf.shaded.exificient.main.api.sax.SAXFactory;
+
+/**
+ * A SAXFactory which hands out {@link ThreadLocalSAXDecoder}s.
+ */
+final class ThreadLocalSAXFactory extends SAXFactory {
+    ThreadLocalSAXFactory(final EXIFactory exiFactory) {
+        super(exiFactory);
+    }
+
+    @Override
+    public ThreadLocalSAXDecoder createEXIReader() throws EXIException {
+        return new ThreadLocalSAXDecoder(exiFactory);
+    }
+}