From f456c7983ded455b006d25a9c5e17401f6c22dca Mon Sep 17 00:00:00 2001
From: Andreas Hansson <andreas.hansson@arm.com>
Date: Mon, 7 Jan 2013 13:05:37 -0500
Subject: mem: Add tracing support in the communication monitor

This patch adds packet tracing to the communication monitor using a
protobuf as the mechanism for creating the trace.

If no file is specified, then the tracing is disabled. If a file is
specified, then for every packet that is successfully sent, a protobuf
message is serialized to the file.
---
 src/mem/CommMonitor.py  |  3 +++
 src/mem/SConscript      |  8 ++++++--
 src/mem/comm_monitor.cc | 48 +++++++++++++++++++++++++++++++++++++++++++++++-
 src/mem/comm_monitor.hh | 12 +++++++++++-
 4 files changed, 67 insertions(+), 4 deletions(-)

(limited to 'src/mem')

diff --git a/src/mem/CommMonitor.py b/src/mem/CommMonitor.py
index a34a57db4..3f9106cc4 100644
--- a/src/mem/CommMonitor.py
+++ b/src/mem/CommMonitor.py
@@ -49,6 +49,9 @@ class CommMonitor(MemObject):
     master = MasterPort("Master port")
     slave = SlavePort("Slave port")
 
+    # packet trace output file, disabled by default
+    trace_file = Param.String("", "Packet trace output file")
+
     # control the sample period window length of this monitor
     sample_period = Param.Clock("1ms", "Sample period for histograms")
 
diff --git a/src/mem/SConscript b/src/mem/SConscript
index 374f904a8..ca89418b5 100644
--- a/src/mem/SConscript
+++ b/src/mem/SConscript
@@ -30,17 +30,21 @@
 
 Import('*')
 
+# Only build the communication if we have support for protobuf as the
+# tracing relies on it
+if env['HAVE_PROTOBUF']:
+    SimObject('CommMonitor.py')
+    Source('comm_monitor.cc')
+
 SimObject('AddrMapper.py')
 SimObject('Bridge.py')
 SimObject('Bus.py')
-SimObject('CommMonitor.py')
 SimObject('MemObject.py')
 
 Source('addr_mapper.cc')
 Source('bridge.cc')
 Source('bus.cc')
 Source('coherent_bus.cc')
-Source('comm_monitor.cc')
 Source('mem_object.cc')
 Source('mport.cc')
 Source('noncoherent_bus.cc')
diff --git a/src/mem/comm_monitor.cc b/src/mem/comm_monitor.cc
index 7e98f64f6..88e549cbb 100644
--- a/src/mem/comm_monitor.cc
+++ b/src/mem/comm_monitor.cc
@@ -38,9 +38,12 @@
  *          Andreas Hansson
  */
 
+#include "base/callback.hh"
+#include "base/output.hh"
 #include "base/trace.hh"
 #include "debug/CommMonitor.hh"
 #include "mem/comm_monitor.hh"
+#include "proto/packet.pb.h"
 #include "sim/stats.hh"
 
 CommMonitor::CommMonitor(Params* params)
@@ -51,8 +54,31 @@ CommMonitor::CommMonitor(Params* params)
       samplePeriodTicks(params->sample_period),
       readAddrMask(params->read_addr_mask),
       writeAddrMask(params->write_addr_mask),
-      stats(params)
+      stats(params),
+      traceStream(NULL)
 {
+    // If we are using a trace file, then open the file,
+    if (params->trace_file != "") {
+        // If the trace file is not specified as an absolute path,
+        // append the current simulation output directory
+        std::string filename = simout.resolve(params->trace_file);
+        traceStream = new ProtoOutputStream(filename);
+
+        // Create a protobuf message for the header and write it to
+        // the stream
+        Message::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.
+        Callback* cb = new MakeCallback<CommMonitor,
+            &CommMonitor::closeStreams>(this);
+        registerExitCallback(cb);
+    }
+
     // keep track of the sample period both in ticks and absolute time
     samplePeriod.setTick(params->sample_period);
 
@@ -61,6 +87,13 @@ CommMonitor::CommMonitor(Params* params)
             name(), samplePeriodTicks, samplePeriod);
 }
 
+void
+CommMonitor::closeStreams()
+{
+    if (traceStream != NULL)
+        delete traceStream;
+}
+
 CommMonitor*
 CommMonitorParams::create()
 {
@@ -154,6 +187,19 @@ CommMonitor::recvTimingReq(PacketPtr pkt)
         pkt->senderState = senderState;
     }
 
+    if (successful && traceStream != NULL) {
+        // Create a protobuf message representing the
+        // packet. Currently we do not preserve the flags in the
+        // trace.
+        Message::Packet pkt_msg;
+        pkt_msg.set_tick(curTick());
+        pkt_msg.set_cmd(pkt->cmdToIndex());
+        pkt_msg.set_addr(pkt->getAddr());
+        pkt_msg.set_size(pkt->getSize());
+
+        traceStream->write(pkt_msg);
+    }
+
     if (successful && isRead) {
         DPRINTF(CommMonitor, "Forwarded read request\n");
 
diff --git a/src/mem/comm_monitor.hh b/src/mem/comm_monitor.hh
index e59b8c467..271ae5fff 100644
--- a/src/mem/comm_monitor.hh
+++ b/src/mem/comm_monitor.hh
@@ -45,6 +45,7 @@
 #include "base/time.hh"
 #include "mem/mem_object.hh"
 #include "params/CommMonitor.hh"
+#include "proto/protoio.hh"
 
 /**
  * The communication monitor is a MemObject which can monitor statistics of
@@ -75,7 +76,13 @@ class CommMonitor : public MemObject
     CommMonitor(Params* params);
 
     /** Destructor */
-    ~CommMonitor() { }
+    ~CommMonitor() {}
+
+    /**
+     * Callback to flush and close all open output streams on exit. If
+     * we were calling the destructor it could be done there.
+     */
+    void closeStreams();
 
     virtual BaseMasterPort& getMasterPort(const std::string& if_name,
                                           PortID idx = InvalidPortID);
@@ -427,6 +434,9 @@ class CommMonitor : public MemObject
 
     /** Instantiate stats */
     MonitorStats stats;
+
+    /** Output stream for a potential trace. */
+    ProtoOutputStream* traceStream;
 };
 
 #endif //__MEM_COMM_MONITOR_HH__
-- 
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