[jboss-dev-forums] [Design the new POJO MicroContainer] - VFS Performance

[adrian@jboss.org]

Besides the AOP usage, the other major thing I'm seeing
using hprof for sampling is the VFS usage by the classloader.
I'll show some typical stacktraces:

Not much we can do about the biggest one,
since this is the JDK parsing the bytecode.

The only way to reduce this, is the reduce the number of classes loaded.


  |         java.lang.ClassLoader.defineClass1(ClassLoader.java:Unknown line)
  |         java.lang.ClassLoader.defineClass(ClassLoader.java:620)
  |         org.jboss.classloader.spi.base.BaseClassLoader.access$200(BaseClassLoader.java:62)
  |         org.jboss.classloader.spi.base.BaseClassLoader$2.run(BaseClassLoader.java:504)
  |         org.jboss.classloader.spi.base.BaseClassLoader$2.run(BaseClassLoader.java:464)
  |         java.security.AccessController.doPrivileged(AccessController.java:Unknown line)
  |         org.jboss.classloader.spi.base.BaseClassLoader.loadClassLocally(BaseClassLoader.java:462)
  |         org.jboss.classloader.spi.base.BaseClassLoader.loadClassLocally(BaseClassLoader.java:439)
  |         org.jboss.classloader.spi.base.BaseDelegateLoader.loadClass(BaseDelegateLoader.java:134)
  |         org.jboss.classloader.spi.filter.FilteredDelegateLoader.loadClass(FilteredDelegateLoader.java:131)
  | 

Reading byte code from zip files

  |         java.util.zip.Inflater.inflateBytes(Inflater.java:Unknown line)
  |         java.util.zip.Inflater.inflate(Inflater.java:215)
  |         java.util.zip.InflaterInputStream.read(InflaterInputStream.java:128)
  |         java.io.FilterInputStream.read(FilterInputStream.java:90)
  |         org.jboss.virtual.plugins.context.zip.ZipEntryInputStream.read(ZipEntryInputStream.java:112)
  |         org.jboss.classloader.plugins.ClassLoaderUtils.loadByteCode(ClassLoaderUtils.java:150)
  |         org.jboss.classloader.spi.base.BaseClassLoader$2.run(BaseClassLoader.java:475)
  |         org.jboss.classloader.spi.base.BaseClassLoader$2.run(BaseClassLoader.java:464)
  |         java.security.AccessController.doPrivileged(AccessController.java:Unknown line)
  |         org.jboss.classloader.spi.base.BaseClassLoader.loadClassLocally(BaseClassLoader.java:462)
  | 

This looks inefficient, it is listing a parent directory when we do getChild


  |         java.io.UnixFileSystem.checkAccess(UnixFileSystem.java:Unknown line)
  |         java.io.File.canRead(File.java:660)
  |         org.jboss.virtual.plugins.context.file.FileHandler.getChildren(FileHandler.java:161)
  |         org.jboss.virtual.plugins.context.file.FileSystemContext.createVirtualFileHandler(FileSystemContext.java:337)
  |         org.jboss.virtual.plugins.context.file.FileSystemContext.createVirtualFileHandler(FileSystemContext.java:256)
  |         org.jboss.virtual.plugins.context.file.FileHandler.createChildHandler(FileHandler.java:224)
  |         org.jboss.virtual.plugins.context.AbstractVirtualFileHandler.structuredFindChild(AbstractVirtualFileHandler.java:509)
  |         org.jboss.virtual.plugins.context.file.FileHandler.getChild(FileHandler.java:233)
  |         org.jboss.virtual.VirtualFile.getChild(VirtualFile.java:427)
  |         org.jboss.classloading.spi.vfs.policy.VFSClassLoaderPolicy.findVirtualFileInfo(VFSClassLoaderPolicy.java:488)
  | 

Modified checking


  |         java.io.UnixFileSystem.getLastModifiedTime(UnixFileSystem.java:Unknown line)
  |         java.io.File.lastModified(File.java:795)
  |         org.jboss.virtual.plugins.context.zip.ZipFileWrapper.getLastModified(ZipFileWrapper.java:140)
  |         org.jboss.virtual.plugins.context.zip.ZipEntryContext.getLastModified(ZipEntryContext.java:682)
  |         org.jboss.virtual.plugins.context.zip.ZipEntryHandler.getLastModified(ZipEntryHandler.java:92)
  |         org.jboss.virtual.plugins.context.DelegatingHandler.getLastModified(DelegatingHandler.java:107)
  |         org.jboss.virtual.plugins.context.AbstractVirtualFileHandler.hasBeenModified(AbstractVirtualFileHandler.java:181)
  |         org.jboss.virtual.plugins.context.file.FileHandler.getChildren(FileHandler.java:183)
  |         org.jboss.virtual.plugins.context.file.FileSystemContext.createVirtualFileHandler(FileSystemContext.java:337)
  |         org.jboss.virtual.plugins.context.file.FileSystemContext.createVirtualFileHandler(FileSystemContext.java:256)
  | 

I keep seeing this, not checked if it is a real inefficiency


  |         org.jboss.virtual.plugins.context.AbstractVirtualFileHandler.getLocalPathName(AbstractVirtualFileHandler.java:230)
  |         org.jboss.virtual.plugins.context.zip.ZipEntryContext.isLeaf(ZipEntryContext.java:751)
  |         org.jboss.virtual.plugins.context.zip.ZipEntryHandler.isLeaf(ZipEntryHandler.java:110)
  |         org.jboss.virtual.plugins.context.AbstractVirtualFileHandler.structuredFindChild(AbstractVirtualFileHandler.java:502)
  |         org.jboss.virtual.plugins.context.zip.ZipEntryHandler.getChild(ZipEntryHandler.java:139)
  |         org.jboss.virtual.plugins.context.DelegatingHandler.getChild(DelegatingHandler.java:93)
  |         org.jboss.virtual.VirtualFile.getChild(VirtualFile.java:427)
  |         org.jboss.classloading.spi.vfs.policy.VFSClassLoaderPolicy.findVirtualFileInfo(VFSClassLoaderPolicy.java:488)
  |         org.jboss.classloading.spi.vfs.policy.VFSClassLoaderPolicy.findChild(VFSClassLoaderPolicy.java:452)
  |         org.jboss.classloading.spi.vfs.policy.VFSClassLoaderPolicy.getResource(VFSClassLoaderPolicy.java:385)
  | 

Similarly this


  |         java.util.concurrent.ConcurrentHashMap$Segment.get(ConcurrentHashMap.java:334)
  |         java.util.concurrent.ConcurrentHashMap.get(ConcurrentHashMap.java:731)
  |         org.jboss.virtual.plugins.context.zip.ZipEntryContext.getRoot(ZipEntryContext.java:606)
  |         org.jboss.virtual.plugins.context.AbstractVirtualFileHandler.getLocalPathName(AbstractVirtualFileHandler.java:230)
  |         org.jboss.virtual.plugins.context.zip.ZipEntryContext.isLeaf(ZipEntryContext.java:751)
  |         org.jboss.virtual.plugins.context.zip.ZipEntryHandler.isLeaf(ZipEntryHandler.java:110)
  |         org.jboss.virtual.plugins.context.AbstractVirtualFileHandler.structuredFindChild(AbstractVirtualFileHandler.java:502)
  |         org.jboss.virtual.plugins.context.zip.ZipEntryHandler.getChild(ZipEntryHandler.java:139)
  |         org.jboss.virtual.plugins.context.DelegatingHandler.getChild(DelegatingHandler.java:93)
  |         org.jboss.virtual.VirtualFile.getChild(VirtualFile.java:427)
  | 

I'm still seeing the PathTokenizer showing up


  |         org.jboss.virtual.plugins.vfs.helpers.PathTokenizer.getTokens(PathTokenizer.java:97)
  |         org.jboss.virtual.plugins.context.AbstractVirtualFileHandler.structuredFindChild(AbstractVirtualFileHandler.java:475)
  |         org.jboss.virtual.plugins.context.zip.ZipEntryHandler.getChild(ZipEntryHandler.java:139)
  |         org.jboss.virtual.plugins.context.DelegatingHandler.getChild(DelegatingHandler.java:93)
  |         org.jboss.virtual.VirtualFile.getChild(VirtualFile.java:427)
  |         org.jboss.classloading.spi.vfs.policy.VFSClassLoaderPolicy.findVirtualFileInfo(VFSClassLoaderPolicy.java:488)
  |         org.jboss.classloading.spi.vfs.policy.VFSClassLoaderPolicy.findChild(VFSClassLoaderPolicy.java:452)
  |         org.jboss.classloading.spi.vfs.policy.VFSClassLoaderPolicy.getResource(VFSClassLoaderPolicy.java:385)
  |         org.jboss.classloader.spi.base.BaseClassLoader$3.run(BaseClassLoader.java:567)
  |         org.jboss.classloader.spi.base.BaseClassLoader$3.run(BaseClassLoader.java:564)
  | 

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