mem-cache: Add MSHR debuging information

Add debug statment in MSHR and MSHRQueue class to track the
number of free MSHR each time a new one is allocated/deallocated.

Also track the allocation/deallocation of each MSHR target.

Change-Id: I2533e7660da1cde3052425f8db8852e59d463b42
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/47041
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Daniel Carvalho <odanrc@yahoo.com.br>
Tested-by: kokoro <noreply+kokoro@google.com>

src/mem/cache/mshr.cc

@@ -178,6 +178,8 @@ MSHR::TargetList::add(PacketPtr pkt, Tick readyTime,
     }
 
     emplace_back(pkt, readyTime, order, source, markPending, alloc_on_fill);
+
+    DPRINTF(MSHR, "New target allocated: %s\n", pkt->print());
 }
 
 
@@ -411,6 +413,8 @@ MSHR::allocateTarget(PacketPtr pkt, Tick whenReady, Counter _order,
         targets.add(pkt, whenReady, _order, Target::FromCPU, !inService,
                     alloc_on_fill);
     }
+
+    DPRINTF(MSHR, "After target allocation: %s", print());
 }
 
 bool
@@ -719,12 +723,12 @@ MSHR::print(std::ostream &os, int verbosity, const std::string &prefix) const
              hasFromCache() ? "HasFromCache" : "");
 
     if (!targets.empty()) {
-        ccprintf(os, "%s  Targets:\n", prefix);
-        targets.print(os, verbosity, prefix + "    ");
+        ccprintf(os, "%s      Targets:\n", prefix);
+        targets.print(os, verbosity, prefix + "        ");
     }
     if (!deferredTargets.empty()) {
-        ccprintf(os, "%s  Deferred Targets:\n", prefix);
-        deferredTargets.print(os, verbosity, prefix + "      ");
+        ccprintf(os, "%s      Deferred Targets:\n", prefix);
+        deferredTargets.print(os, verbosity, prefix + "        ");
     }
 }
 

src/mem/cache/mshr.hh

@@ -53,7 +53,9 @@
 #include <vector>
 
 #include "base/printable.hh"
+#include "base/trace.hh"
 #include "base/types.hh"
+#include "debug/MSHR.hh"
 #include "mem/cache/queue_entry.hh"
 #include "mem/packet.hh"
 #include "mem/request.hh"
@@ -460,6 +462,8 @@ class MSHR : public QueueEntry, public Printable
      */
     void popTarget()
     {
+        DPRINTF(MSHR, "Force deallocating MSHR targets: %s\n",
+                targets.front().pkt->print());
         targets.pop_front();
     }
 

src/mem/cache/mshr_queue.cc

@@ -46,6 +46,7 @@
 
 #include <cassert>
 
+#include "debug/MSHR.hh"
 #include "mem/cache/mshr.hh"
 
 MSHRQueue::MSHRQueue(const std::string &_label,
@@ -64,6 +65,9 @@ MSHRQueue::allocate(Addr blk_addr, unsigned blk_size, PacketPtr pkt,
     assert(mshr->getNumTargets() == 0);
     freeList.pop_front();
 
+    DPRINTF(MSHR, "Allocating new MSHR. Number in use will be %lu/%lu\n",
+            allocatedList.size() + 1, numEntries);
+
     mshr->allocate(blk_addr, blk_size, pkt, when_ready, order, alloc_on_fill);
     mshr->allocIter = allocatedList.insert(allocatedList.end(), mshr);
     mshr->readyIter = addToReadyList(mshr);
@@ -72,6 +76,17 @@ MSHRQueue::allocate(Addr blk_addr, unsigned blk_size, PacketPtr pkt,
     return mshr;
 }
 
+void
+MSHRQueue::deallocate(MSHR* mshr)
+{
+
+    DPRINTF(MSHR, "Deallocating all targets: %s", mshr->print());
+    Queue<MSHR>::deallocate(mshr);
+    DPRINTF(MSHR, "MSHR deallocated. Number in use: %lu/%lu\n",
+            allocatedList.size(), numEntries);
+}
+
+
 void
 MSHRQueue::moveToFront(MSHR *mshr)
 {

src/mem/cache/mshr_queue.hh

@@ -96,6 +96,11 @@ class MSHRQueue : public Queue<MSHR>
     MSHR *allocate(Addr blk_addr, unsigned blk_size, PacketPtr pkt,
                    Tick when_ready, Counter order, bool alloc_on_fill);
 
+    /**
+     * Deallocate a MSHR and its targets
+     */
+    void deallocate(MSHR *mshr) override;
+
     /**
      * Moves the MSHR to the front of the pending list if it is not
      * in service.

src/mem/cache/queue.hh

@@ -234,7 +234,8 @@ class Queue : public Drainable, public Named
      *
      * @param entry
      */
-    void deallocate(Entry *entry)
+    virtual void
+    deallocate(Entry *entry)
     {
         allocatedList.erase(entry->allocIter);
         freeList.push_front(entry);