probe: Add probe in Fetch, IEW, Rename and Commit

This patch adds probe points in Fetch, IEW, Rename and Commit stages as follows.

A probe point is added in the Fetch stage for probing when a fetch request is
sent. Notify is fired on the probe point when a request is sent succesfully in
the first attempt as well as on a retry attempt.

Probe points are added in the IEW stage when an instruction begins to execute
and when execution is complete. This points can be used for monitoring the
execution time of an instruction.

Probe points are added in the Rename stage to probe renaming of source and
destination registers and when there is squashing. These probe points can be
used to track register dependencies and remove when there is squashing.

A probe point for squashing is added in Commit to probe squashed instructions.

1 files changed, 19 insertions, 0 deletions

diff --git a/src/cpu/o3/iew_impl.hh b/src/cpu/o3/iew_impl.hh
index ae76aa9e1..e02429b14 100644
--- a/src/cpu/o3/iew_impl.hh
+++ b/src/cpu/o3/iew_impl.hh
@@ -125,6 +125,18 @@ DefaultIEW<Impl>::regProbePoints()
 {
     ppDispatch = new ProbePointArg<DynInstPtr>(cpu->getProbeManager(), "Dispatch");
     ppMispredict = new ProbePointArg<DynInstPtr>(cpu->getProbeManager(), "Mispredict");
+    /**
+     * Probe point with dynamic instruction as the argument used to probe when
+     * an instruction starts to execute.
+     */
+    ppExecute = new ProbePointArg<DynInstPtr>(cpu->getProbeManager(),
+                                              "Execute");
+    /**
+     * Probe point with dynamic instruction as the argument used to probe when
+     * an instruction execution completes and it is marked ready to commit.
+     */
+    ppToCommit = new ProbePointArg<DynInstPtr>(cpu->getProbeManager(),
+                                               "ToCommit");
 }
 
 template <class Impl>
@@ -1190,6 +1202,10 @@ DefaultIEW<Impl>::executeInsts()
         DPRINTF(IEW, "Execute: Processing PC %s, [tid:%i] [sn:%i].\n",
                 inst->pcState(), inst->threadNumber,inst->seqNum);
 
+        // Notify potential listeners that this instruction has started
+        // executing
+        ppExecute->notify(inst);
+
         // Check if the instruction is squashed; if so then skip it
         if (inst->isSquashed()) {
             DPRINTF(IEW, "Execute: Instruction was squashed. PC: %s, [tid:%i]"
@@ -1402,6 +1418,9 @@ DefaultIEW<Impl>::writebackInsts()
                 inst->seqNum, inst->pcState());
 
         iewInstsToCommit[tid]++;
+        // Notify potential listeners that execution is complete for this
+        // instruction.
+        ppToCommit->notify(inst);
 
         // Some instructions will be sent to commit without having
         // executed because they need commit to handle them.