mem: Fill the new packet ID fields with master IDs when tracing packets.

This will let somebody consuming the memory packet trace make sense out of
the master IDs passed along with individual accesses.

Change-Id: I621d915f218728066ce95e6fc81f36d14ae7e597
Reviewed-on: https://gem5-review.googlesource.com/4800
Reviewed-by: Rahul Thakur <rjthakur@google.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>

3 files changed, 26 insertions, 6 deletions

diff --git a/src/mem/probes/MemTraceProbe.py b/src/mem/probes/MemTraceProbe.py
index c51ec9282..8daf94dbd 100644
--- a/src/mem/probes/MemTraceProbe.py
+++ b/src/mem/probes/MemTraceProbe.py
@@ -52,3 +52,5 @@ class MemTraceProbe(BaseMemProbe):
     # packet trace output file, disabled by default
     trace_file = Param.String("", "Packet trace output file")
 
+    # System object to look up the name associated with a master ID
+    system = Param.System(Parent.any, "System the probe belongs to")
diff --git a/src/mem/probes/mem_trace.cc b/src/mem/probes/mem_trace.cc
index 465c10004..6e55c48a1 100644
--- a/src/mem/probes/mem_trace.cc
+++ b/src/mem/probes/mem_trace.cc
@@ -44,10 +44,12 @@
 #include "base/output.hh"
 #include "params/MemTraceProbe.hh"
 #include "proto/packet.pb.h"
+#include "sim/system.hh"
 
 MemTraceProbe::MemTraceProbe(MemTraceProbeParams *p)
     : BaseMemProbe(p),
       traceStream(nullptr),
+      system(p->system),
       withPC(p->with_pc)
 {
     std::string filename;
@@ -72,18 +74,29 @@ MemTraceProbe::MemTraceProbe(MemTraceProbeParams *p)
 
     traceStream = new ProtoOutputStream(filename);
 
+    // Register a callback to compensate for the destructor not
+    // being called. The callback forces the stream to flush and
+    // closes the output file.
+    registerExitCallback(
+        new MakeCallback<MemTraceProbe, &MemTraceProbe::closeStreams>(this));
+}
+
+void
+MemTraceProbe::startup()
+{
     // Create a protobuf message for the header and write it to
     // the stream
     ProtoMessage::PacketHeader header_msg;
     header_msg.set_obj_id(name());
     header_msg.set_tick_freq(SimClock::Frequency);
-    traceStream->write(header_msg);
 
-    // Register a callback to compensate for the destructor not
-    // being called. The callback forces the stream to flush and
-    // closes the output file.
-    registerExitCallback(
-        new MakeCallback<MemTraceProbe, &MemTraceProbe::closeStreams>(this));
+    for (int i = 0; i < system->maxMasters(); i++) {
+        auto id_string = header_msg.add_id_strings();
+        id_string->set_key(i);
+        id_string->set_value(system->getMasterName(i));
+    }
+
+    traceStream->write(header_msg);
 }
 
 void
diff --git a/src/mem/probes/mem_trace.hh b/src/mem/probes/mem_trace.hh
index 158c5aacb..51abebcf3 100644
--- a/src/mem/probes/mem_trace.hh
+++ b/src/mem/probes/mem_trace.hh
@@ -45,6 +45,7 @@
 #include "proto/protoio.hh"
 
 struct MemTraceProbeParams;
+class System;
 
 class MemTraceProbe : public BaseMemProbe
 {
@@ -60,11 +61,15 @@ class MemTraceProbe : public BaseMemProbe
      */
     void closeStreams();
 
+    void startup() override;
+
   protected:
 
     /** Trace output stream */
     ProtoOutputStream *traceStream;
 
+    System *system;
+
   private:
 
     /** Include the Program Counter in the memory trace */