2 files changed, 56 insertions, 0 deletions

diff --git a/src/python/m5/simulate.py b/src/python/m5/simulate.py
index d89629d2d..5d70f4b18 100644
--- a/src/python/m5/simulate.py
+++ b/src/python/m5/simulate.py
@@ -312,4 +312,57 @@ def notifyFork(root):
     for obj in root.descendants():
         obj.notifyFork()
 
+fork_count = 0
+def fork(simout="%(parent)s.f%(fork_seq)i"):
+    """Fork the simulator.
+
+    This function forks the simulator. After forking the simulator,
+    the child process gets its output files redirected to a new output
+    directory. The default name of the output directory is the same as
+    the parent with the suffix ".fN" added where N is the fork
+    sequence number. The name of the output directory can be
+    overridden using the simout keyword argument.
+
+    Output file formatting dictionary:
+      parent -- Path to the parent process's output directory.
+      fork_seq -- Fork sequence number.
+      pid -- PID of the child process.
+
+    Keyword Arguments:
+      simout -- New simulation output directory.
+
+    Return Value:
+      pid of the child process or 0 if running in the child.
+    """
+    from m5 import options
+    global fork_count
+
+    if not internal.core.listenersDisabled():
+        raise RuntimeError, "Can not fork a simulator with listeners enabled"
+
+    drain()
+
+    try:
+        pid = os.fork()
+    except OSError, e:
+        raise e
+
+    if pid == 0:
+        # In child, notify objects of the fork
+        root = objects.Root.getInstance()
+        notifyFork(root)
+        # Setup a new output directory
+        parent = options.outdir
+        options.outdir = simout % {
+                "parent" : parent,
+                "fork_seq" : fork_count,
+                "pid" : os.getpid(),
+                }
+        core.setOutputDir(options.outdir)
+    else:
+        fork_count += 1
+
+    return pid
+
 from internal.core import disableAllListeners
+from internal.core import listenersDisabled
diff --git a/src/python/swig/core.i b/src/python/swig/core.i
index 862c0e37e..08fbe01d1 100644
--- a/src/python/swig/core.i
+++ b/src/python/swig/core.i
@@ -55,6 +55,8 @@ const bool flag_TRACING_ON = TRACING_ON;
 
 inline void disableAllListeners() { ListenSocket::disableAll(); }
 
+inline bool listenersDisabled() { return ListenSocket::allDisabled(); }
+
 inline void
 seedRandom(uint64_t seed)
 {
@@ -71,6 +73,7 @@ seedRandom(uint64_t seed)
 void setOutputDir(const std::string &dir);
 void doExitCleanup();
 void disableAllListeners();
+bool listenersDisabled();
 void seedRandom(uint64_t seed);
 
 %immutable compileDate;