-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Chuck,
Caldarale, Charles R wrote: >> From: Christopher Schultz [mailto:[EMAIL PROTECTED] >> Subject: Re: Tomcat threads >> >> recent JVMs use shared memory to share common class data >> (like JITed object code from java.* packages) > > Careful - JITed code is *not* shared - only some of the PermGen is, > and that only on a -client JVM. When running -server mode, nothing is > shared across JVMs (that may change in Java SE 7 - haven't checked yet). > The PermGen contains loaded classes, but not JIT-generated code. Thanks for clearing that up; I especially didn't know that -client was required. PermGen seems like an odd item to share... though I guess all those java.lang.Package, java.lang.Class, java.lang.Method, etc. objects can really beat a system down. I was under the impression that only java.* classes were shared, and not just anything that was loaded by a bootstrap classloader (see your other post for that speculation). It would seem odd to share, say, Tomcat's classes with other -client JVMs. For those interested in reading more, here is Sun's documentation for this feature: http://java.sun.com/javase/6/docs/technotes/guides/vm/class-data-sharing.html If you use IBM's JVM, here is some info on class sharing, which works differently (article is a bit outdated): http://www.ibm.com/developerworks/java/library/j-ibmjava4/ - -chris -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEARECAAYFAkkbMAcACgkQ9CaO5/Lv0PDWRgCgoE72SJ1cS7nKvSHh0KoGdxcC 5IgAoJHn4A+p+jjy8Ad3FgylzpRhpn7N =pd2w -----END PGP SIGNATURE----- --------------------------------------------------------------------- To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
