On Mon, 07 August 2000, Mo DeJong wrote: > >From section 3.2 in blendchanges.txt: > > load "tclblend", "tcl" .dll or .so (a) > call "new Interp()" in Java > invoke Java_tcl_lang_Interp_create() C function (b) > calls JavaSetupJava() > invoke Java_tcl_lang_Interp_init() C function (c) > > We do need a mutex around the init of tsdPtr->currentEnv > and tsdPtr->initialized_currentEnv. These are set the > first time JavaGetEnv() is called, but JavaGetEnv() > is not called when Tcl Blend is loaded from Java. Unless I am missing something about thread local storage, my understanding is that each thread can only access its own thread local storage. As a result, all access to thread local storage is serialized and it is not possible for two different threads to try to initialize tsdPtr->initialized_currentEnv. Hence, there is no need for synchronization. See item 4.3 in http://www-cs-students.stanford.edu/~jwu/blendchanges.txt 4.3 Calling JavaGetEnv() ... JavaGetEnv() does: a. creates a JVM if one does not exist b. saves the JVM environemnt in thread local storage if it is not saved already c. returns the JVM environment in thread local storage .... If the interpreter is created from Java using "new tcl.lang.Interp()", the JVM is already setup, but the thread local storage is not. The very first call to JavaGetEnv() will setup the thread local storage and subsequent calls to JavaGetEnv() will simply return the saved environment. In JavaGetEnv(), only step a requires synchronization. Step b and c do not require synchronization because they access the thread local storage. > Any comments on this approach? I like it a bit better > than grabbing the lock before calling JavaGetEnv or > JavaSetupJava, the code seems a bit more clean with > the synchronization inside the methods. Let's see what is the right logic first. The TclBlend intialization involves three major steps: 1. create JVM 2. setup and get JNIEnv in thread local storage. 3. setup JVM with TclBlend related class/method cache Steps 1, 2, and 3 are required for loading TclBlend into Tcl. Step 3 is required for loading TclBlend into Java. Therefore, synchronization should be placed around 1, 2, and 3 in TclBlend_Init. Synchronization should be placed around 3 in Interp_init. After initialization, only 2 is used. 2 does not require synchronization after initialization. -- Jiang Wu [EMAIL PROTECTED] ---------------------------------------------- [EMAIL PROTECTED] is brought to you by the Stanford Alumni Association and Critical Path. ---------------------------------------------------------------- The TclJava mailing list is sponsored by Scriptics Corporation. To subscribe: send mail to [EMAIL PROTECTED] with the word SUBSCRIBE as the subject. To unsubscribe: send mail to [EMAIL PROTECTED] with the word UNSUBSCRIBE as the subject. To send to the list, send email to '[EMAIL PROTECTED]'. An archive is available at http://www.mail-archive.com/tcljava@scriptics.com
