On Sunday 24 December 2006 23:01 Gregory Shimansky wrote: > On Saturday 23 December 2006 20:48 Mikhail Loenko wrote: > > Can you publish most common stacks for the > > "157114 Ljava/io/ByteArrayOutputStream;.write(I)V" > > Yes I've been going to do this for some time already and now that you've > asked, I have finally written a modified agent version which can monitor a > method which is specified on the command line. The agent code is available > at [1] (run like > this: > -agentlib:methodee-stack='Ljava/io/ByteArrayOutputStream;.write(I)V'). > > After the log is generated it can be parsed with the following script > > cat method_stack.log | sort | uniq -c | sort -nr | sed -e 's/ /\n/g' > > I've found that Ljava/io/ByteArrayOutputStream;.write(I)V is used only in 9 > different stacks when running hello world. The most popular stack trace > which is used 147319 times looks like this:
To make things clear, in the following stack trace the numbers at line ends are not source line numbers. These are java bytecode numbers inside of the method. > Ljava/io/ByteArrayOutputStream;.write(I)V:0 > Ljava/util/jar/InitManifest;.nextChunk(Ljava/io/InputStream;Ljava/util/List >;) [B:310 > Ljava/util/jar/InitManifest;.<init>(Ljava/io/InputStream;Ljava/util/jar/Att >ributes;Ljava/util/Map;Ljava/util/Map;Ljava/lang/String;)V:373 > Ljava/util/jar/Manifest;.read(Ljava/io/InputStream;)V:20 > Ljava/util/jar/Manifest;.<init>(Ljava/io/InputStream;Z)V:45 > Ljava/util/jar/JarFile;.getManifest()Ljava/util/jar/Manifest;:92 > Ljava/net/URLClassLoader;.explore(Ljava/net/URL;I)[Ljava/net/URL;:475 > Ljava/net/URLClassLoader;.findClassImpl([Ljava/net/URL;Ljava/lang/String;)L >java/lang/Class;:897 Ljava/net/URLClassLoader$4;.run()Ljava/lang/Class;:14 > Ljava/net/URLClassLoader$4;.run()Ljava/lang/Object;:0 > Ljava/security/AccessController;.doPrivilegedImpl(Ljava/security/Privileged >Action;Ljava/security/AccessControlContext;)Ljava/lang/Object;:82 > Ljava/security/AccessController;.doPrivileged(Ljava/security/PrivilegedActi >on;Ljava/security/AccessControlContext;)Ljava/lang/Object;:15 > Ljava/net/URLClassLoader;.findClass(Ljava/lang/String;)Ljava/lang/Class;:12 > Ljava/lang/ClassLoader;.loadClass(Ljava/lang/String;Z)Ljava/lang/Class;:49 > Ljava/lang/ClassLoader$SystemClassLoader;.loadClass(Ljava/lang/String;Z)Lja >va/lang/Class;:64 > Ljava/lang/ClassLoader;.loadClass(Ljava/lang/String;)Ljava/lang/Class;:2 > > The rest 8 different stack traces differ only after > Ljava/util/jar/Manifest;.read(Ljava/io/InputStream;)V:20 line. The top 2 > methods are called from different locations of > Ljava/util/jar/InitManifest;.<init>(Ljava/io/InputStream;Ljava/util/jar/Att >ributes;Ljava/util/Map;Ljava/util/Map;Ljava/lang/String;)V and > Ljava/util/jar/InitManifest;.nextChunk(Ljava/io/InputStream;Ljava/util/List >;) [B. I am afraid the manifest parsing code has to be changed to improve > its performance. > > [1] http://people.apache.org/~gshimansky/methodee-stack.cpp > > > 2006/12/23, Gregory Shimansky <[EMAIL PROTECTED]>: > > > On Saturday 23 December 2006 04:09 Stefano Mazzocchi wrote: > > > > Gregory Shimansky wrote: > > > > > I was not aware that drlvm didn't generate MethodEnter/Exit events > > > > > for native methods when I wrote this email. Now after applying > > > > > HARMONY-2828 which fills this gap I've rerun my test agent and the > > > > > top10 for most called methods to run hello world application has > > > > > changed. The new top10 list looks like this: > > > > > > > > > > 157114 Ljava/io/ByteArrayOutputStream;.write(I)V > > > > > 20093 Ljava/lang/Object;.<init>()V > > > > > 13975 Ljava/lang/String;.hashCode()I > > > > > 9301 Ljava/lang/Character;.toLowerCase(C)C > > > > > 7842 Ljava/io/ByteArrayOutputStream;.size()I > > > > > 7692 Ljava/lang/String;.<init>(II[C)V > > > > > 6300 > > > > > Ljava/lang/VMMemoryManager;.arrayCopy(Ljava/lang/Object;ILjava/lang > > > > >/O bjec t;II)V 6300 > > > > > Ljava/lang/System;.arraycopy(Ljava/lang/Object;ILjava/lang/Object;I > > > > >I) V 6248 Ljava/lang/String;.length()I > > > > > 6130 Ljava/lang/String;.substring(II)Ljava/lang/String; > > > > > > > > > > We seem to copy memory really too much... > > > > > > > > Not sure I get these results: assuming a "hello world" application > > > > reads only, why is 80% of the time spent writing? > > > > > > Most of the executed code in the table is what it takes for the system > > > java class loader to find and load hello world application class. I > > > think many of those java.io.ByteArrayOutputStream.write calls are used > > > in JAR files manifest parser which writes to memory byte by byte. Maybe > > > there are other places too. > > > > > > -- > > > Gregory -- Gregory
