X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/2f7c87c6cd0db3f48434559687fdddeaf07c6f50..44da6699977c942b1a34734e118cb9842aaeb94b:/org/simgrid/msg/Process.java diff --git a/org/simgrid/msg/Process.java b/org/simgrid/msg/Process.java index bb9f963062..85d822f408 100644 --- a/org/simgrid/msg/Process.java +++ b/org/simgrid/msg/Process.java @@ -14,6 +14,7 @@ package org.simgrid.msg; import java.util.Arrays; import java.util.Hashtable; import java.util.Vector; +import java.lang.Runnable; import java.util.concurrent.Semaphore; /** @@ -47,7 +48,7 @@ import java.util.concurrent.Semaphore; * */ -public abstract class Process extends Thread { +public abstract class Process implements Runnable { /** * This attribute represents a bind between a java process object and * a native process. Even if this attribute is public you must never @@ -92,22 +93,17 @@ public abstract class Process extends Thread { /* process synchronization tools */ - /* give the full path to semaphore to ensure that our own implementation don't get selected */ - protected java.util.concurrent.Semaphore schedBegin, schedEnd; private boolean nativeStop = false; /** * Default constructor (used in ApplicationHandler to initialize it) */ protected Process() { - super(); this.id = nextProcessId++; this.name = null; this.bind = 0; this.args = new Vector(); this.properties = null; - schedBegin = new java.util.concurrent.Semaphore(0); - schedEnd = new java.util.concurrent.Semaphore(0); } @@ -164,7 +160,7 @@ public abstract class Process extends Thread { public Process(Host host, String name, String[]args) { /* This is the constructor called by all others */ this(); - + this.host = host; if (name == null) throw new NullPointerException("Process name cannot be NULL"); this.name = name; @@ -172,12 +168,6 @@ public abstract class Process extends Thread { this.args = new Vector(); if (null != args) this.args.addAll(Arrays.asList(args)); - - try { - create(host.getName()); - } catch (HostNotFoundException e) { - throw new RuntimeException("The impossible happened (yet again): the host that I have were not found",e); - } this.properties = new Hashtable(); @@ -345,22 +335,22 @@ public abstract class Process extends Thread { * Exit the process */ public native void exit(); - + /** + * This method actually creates and run the process. + * @throws HostNotFoundException + */ + public void start() throws HostNotFoundException { + create(host.getName()); + } + /** * This method runs the process. Il calls the method function that you must overwrite. */ public void run() { String[] args = null; /* do not fill it before the signal or this.args will be empty */ - //waitSignal(); /* wait for other people to fill the process in */ - - try { - schedBegin.acquire(); - } catch(InterruptedException e) { - } - try { args = new String[this.args.size()]; if (this.args.size() > 0) { @@ -369,7 +359,6 @@ public abstract class Process extends Thread { this.main(args); exit(); - schedEnd.release(); } catch(MsgException e) { e.printStackTrace(); Msg.info("Unexpected behavior. Stopping now"); @@ -388,10 +377,9 @@ public abstract class Process extends Thread { * exception now. This should be ok since we ignore only a very specific exception * class and not a generic (such as any RuntimeException). */ - System.err.println(currentThread().getName()+": I ignore that other exception"); + //System.err.println(currentThread().getName()+": I ignore that other exception"); } - Msg.info(" Process " + ((Process) Thread.currentThread()).msgName() + " has been killed."); - schedEnd.release(); + //Msg.info(" Process " + ((Process) Thread.currentThread()).msgName() + " has been killed."); } else { pk.printStackTrace(); @@ -409,90 +397,6 @@ public abstract class Process extends Thread { */ public abstract void main(String[]args) throws MsgException; - - /** @brief Gives the control from the given user thread back to the maestro - * - * schedule() and unschedule() are the basis of interactions between the user threads - * (executing the user code), and the maestro thread (executing the platform models to decide - * which user thread should get executed when. Once it decided which user thread should be run - * (because the blocking action it were blocked onto are terminated in the simulated world), the - * maestro passes the control to this uthread by calling uthread.schedule() in the maestro thread - * (check its code for the simple semaphore-based synchronization schema). - * - * The uthread executes (while the maestro is blocked), until it starts another blocking - * action, such as a communication or so. In that case, uthread.unschedule() gets called from - * the user thread. - * - * As other complications, these methods are called directly by the C through a JNI upcall in - * response to the JNI downcalls done by the Java code. For example, you have this (simplified) - * execution path: - * - a process calls the Task.send() method in java - * - this calls Java_org_simgrid_msg_MsgNative_taskSend() in C through JNI - * - this ends up calling jprocess_unschedule(), still in C - * - this calls the java method "org/simgrid/msg/Process/unschedule()V" through JNI - * - that is to say, the unschedule() method that you are reading the documentation of. - * - * To understand all this, you must keep in mind that there is no difference between the C thread - * describing a process, and the Java thread doing the same. Most of the time, they are system - * threads from the kernel anyway. In the other case (such as when using green java threads when - * the OS does not provide any thread feature), I'm unsure of what happens: it's a very long time - * that I didn't see any such OS. - * - * The synchronization itself is implemented using simple semaphores in Java, as you can see by - * checking the code of these functions (and run() above). That's super simple, and thus welcome - * given the global complexity of the synchronization architecture: getting C and Java cooperate - * with regard to thread handling in a portable manner is very uneasy. A simple and straightforward - * implementation of each synchronization point is precious. - * - * But this kinda limits the system scalability. It may reveal difficult to simulate dozens of - * thousands of processes this way, both for memory limitations and for hard limits pushed by the - * system on the amount of threads and semaphores (we have 2 semaphores per user process). - * - * At time of writing, the best source of information on how to simulate large systems within the - * Java bindings of simgrid is here: http://tomp2p.net/dev/simgrid/ - * - */ - public void unschedule() { - /* this function is called from the user thread only */ - try { - - /* unlock the maestro before going to sleep */ - schedEnd.release(); - /* Here, the user thread is locked, waiting for the semaphore, and maestro executes instead */ - schedBegin.acquire(); - /* now that the semaphore is acquired, it means that maestro gave us the control back */ - - /* the user thread is starting again after giving the control to maestro. - * Let's check if we were asked to die in between */ - if ( (Thread.currentThread() instanceof Process) &&((Process) Thread.currentThread()).getNativeStop()) { - throw new ProcessKilled(); - } - - } catch (InterruptedException e) { - /* ignore this exception because this is how we get killed on process.kill or end of simulation. - * I don't like hiding exceptions this way, but fail to see any other solution - */ - } - - } - - /** @brief Gives the control from the maestro back to the given user thread - * - * Must be called from the maestro thread -- see unschedule() for details. - * - */ - public void schedule() { - try { - /* unlock the user thread before going to sleep */ - schedBegin.release(); - /* Here, maestro is locked, waiting for the schedEnd semaphore to get signaled by used thread, that executes instead */ - schedEnd.acquire(); - /* Maestro now has the control back and the user thread went to sleep gently */ - - } catch(InterruptedException e) { - throw new RuntimeException("The impossible did happend once again: I got interrupted in schedEnd.acquire()",e); - } - } /** * Class initializer, to initialize various JNI stuff