mem: Move trace functionality from the CommMonitor to a probe

This changeset moves the access trace functionality from the
CommMonitor into a separate probe. The probe can be hooked up to any
component that exports probe points of the type ProbePoints::Packet.

This patch moves the dependency on Google's Protocol Buffers library
from the CommMonitor to the MemTraceProbe, which means that the
CommMonitor (including stack distance profiling) no long depends on
it.

9 files changed, 243 insertions, 128 deletions

diff --git a/src/mem/CommMonitor.py b/src/mem/CommMonitor.py
index ba871357d..aa8da62ed 100644
--- a/src/mem/CommMonitor.py
+++ b/src/mem/CommMonitor.py
@@ -53,16 +53,6 @@ class CommMonitor(MemObject):
     master = MasterPort("Master port")
     slave = SlavePort("Slave port")
 
-    # Boolean to enable or disable the trace. Writes to an a file named based on
-    # SimObject hierarchy.
-    trace_enable = Param.Bool(False, "Enable trace capture")
-
-    # Boolean to compress the trace or not.
-    trace_compress = Param.Bool(True, "Enable trace compression")
-
-    # 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 4f1216745..404f4a90f 100644
--- a/src/mem/SConscript
+++ b/src/mem/SConscript
@@ -30,11 +30,8 @@
 
 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('CommMonitor.py')
+Source('comm_monitor.cc')
 
 SimObject('AbstractMemory.py')
 SimObject('AddrMapper.py')
diff --git a/src/mem/comm_monitor.cc b/src/mem/comm_monitor.cc
index 35f4738d6..beb7fe32c 100644
--- a/src/mem/comm_monitor.cc
+++ b/src/mem/comm_monitor.cc
@@ -38,12 +38,9 @@
  *          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)
@@ -55,67 +52,13 @@ CommMonitor::CommMonitor(Params* params)
       samplePeriod(params->sample_period / SimClock::Float::s),
       readAddrMask(params->read_addr_mask),
       writeAddrMask(params->write_addr_mask),
-      system(params->system),
-      traceStream(nullptr),
       stats(params)
 {
-    // If we are using a trace file, then open the file
-    if (params->trace_enable) {
-        std::string filename;
-        if (params->trace_file != "") {
-            // If the trace file is not specified as an absolute path,
-            // append the current simulation output directory
-            filename = simout.resolve(params->trace_file);
-
-            std::string suffix = ".gz";
-            // If trace_compress has been set, check the suffix. Append
-            // accordingly.
-            if (params->trace_compress &&
-                filename.compare(filename.size() - suffix.size(), suffix.size(),
-                                 suffix) != 0)
-                    filename = filename + suffix;
-        } else {
-            // Generate a filename from the name of the SimObject. Append .trc
-            // and .gz if we want compression enabled.
-            filename = simout.resolve(name() + ".trc" +
-                                      (params->trace_compress ? ".gz" : ""));
-        }
-
-        traceStream = new ProtoOutputStream(filename);
-
-        // 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.
-        Callback* cb = new MakeCallback<CommMonitor,
-            &CommMonitor::closeStreams>(this);
-        registerExitCallback(cb);
-    }
-
     DPRINTF(CommMonitor,
             "Created monitor %s with sample period %d ticks (%f ms)\n",
             name(), samplePeriodTicks, samplePeriod * 1E3);
 }
 
-CommMonitor::~CommMonitor()
-{
-    // if not already done, close the stream
-    closeStreams();
-}
-
-void
-CommMonitor::closeStreams()
-{
-    if (traceStream != NULL)
-        delete traceStream;
-}
-
 CommMonitor*
 CommMonitorParams::create()
 {
@@ -128,14 +71,6 @@ CommMonitor::init()
     // make sure both sides of the monitor are connected
     if (!slavePort.isConnected() || !masterPort.isConnected())
         fatal("Communication monitor is not connected on both sides.\n");
-
-    if (traceStream != NULL) {
-        // Check the memory mode. We only record something when in
-        // timing mode. Warn accordingly.
-        if (!system->isTimingMode())
-            warn("%s: Not in timing mode. No trace will be recorded.", name());
-    }
-
 }
 
 void
@@ -182,19 +117,6 @@ CommMonitor::recvAtomic(PacketPtr pkt)
 {
     ppPktReq->notify(pkt);
 
-    // if tracing enabled, store the packet information
-    // to the trace stream
-    if (traceStream != NULL) {
-        ProtoMessage::Packet pkt_msg;
-        pkt_msg.set_tick(curTick());
-        pkt_msg.set_cmd(pkt->cmdToIndex());
-        pkt_msg.set_flags(pkt->req->getFlags());
-        pkt_msg.set_addr(pkt->getAddr());
-        pkt_msg.set_size(pkt->getSize());
-
-        traceStream->write(pkt_msg);
-    }
-
     const Tick delay(masterPort.sendAtomic(pkt));
     assert(pkt->isResponse());
     ppPktResp->notify(pkt);
@@ -218,8 +140,6 @@ CommMonitor::recvTimingReq(PacketPtr pkt)
     const bool is_read = pkt->isRead();
     const bool is_write = pkt->isWrite();
     const MemCmd cmd = pkt->cmd;
-    const int cmd_idx = pkt->cmdToIndex();
-    const Request::FlagsType req_flags = pkt->req->getFlags();
     const unsigned size = pkt->getSize();
     const Addr addr = pkt->getAddr();
     const bool expects_response(
@@ -253,20 +173,6 @@ CommMonitor::recvTimingReq(PacketPtr pkt)
         pkt->cmd = response_cmd;
     }
 
-    if (successful && traceStream != NULL) {
-        // Create a protobuf message representing the
-        // packet. Currently we do not preserve the flags in the
-        // trace.
-        ProtoMessage::Packet pkt_msg;
-        pkt_msg.set_tick(curTick());
-        pkt_msg.set_cmd(cmd_idx);
-        pkt_msg.set_flags(req_flags);
-        pkt_msg.set_addr(addr);
-        pkt_msg.set_size(size);
-
-        traceStream->write(pkt_msg);
-    }
-
     if (successful && is_read) {
         DPRINTF(CommMonitor, "Forwarded read request\n");
 
diff --git a/src/mem/comm_monitor.hh b/src/mem/comm_monitor.hh
index d2ce1d224..fb8f5eeb7 100644
--- a/src/mem/comm_monitor.hh
+++ b/src/mem/comm_monitor.hh
@@ -44,9 +44,7 @@
 #include "base/statistics.hh"
 #include "mem/mem_object.hh"
 #include "params/CommMonitor.hh"
-#include "proto/protoio.hh"
 #include "sim/probe/mem.hh"
-#include "sim/system.hh"
 
 /**
  * The communication monitor is a MemObject which can monitor statistics of
@@ -76,9 +74,6 @@ class CommMonitor : public MemObject
      */
     CommMonitor(Params* params);
 
-    /** Destructor */
-    ~CommMonitor();
-
     void init() M5_ATTR_OVERRIDE;
     void regStats() M5_ATTR_OVERRIDE;
     void startup() M5_ATTR_OVERRIDE;
@@ -391,12 +386,6 @@ class CommMonitor : public MemObject
     /** This function is called periodically at the end of each time bin */
     void samplePeriodic();
 
-    /**
-     * Callback to flush and close all open output streams on exit. If
-     * we were calling the destructor it could be done there.
-     */
-    void closeStreams();
-
     /** Periodic event called at the end of each simulation time bin */
     EventWrapper<CommMonitor, &CommMonitor::samplePeriodic> samplePeriodicEvent;
 
@@ -416,14 +405,8 @@ class CommMonitor : public MemObject
     /** Address mask for sources of write accesses to be captured */
     const Addr writeAddrMask;
 
-    /** The system in which the monitor lives */
-    System *const system;
-
     /** @} */
 
-    /** Output stream for a potential trace. */
-    ProtoOutputStream *traceStream;
-
     /** Instantiate stats */
     MonitorStats stats;
 
diff --git a/src/mem/probes/MemTraceProbe.py b/src/mem/probes/MemTraceProbe.py
new file mode 100644
index 000000000..971765eb4
--- /dev/null
+++ b/src/mem/probes/MemTraceProbe.py
@@ -0,0 +1,51 @@
+# Copyright (c) 2014-2015 ARM Limited
+# All rights reserved.
+#
+# The license below extends only to copyright in the software and shall
+# not be construed as granting a license to any other intellectual
+# property including but not limited to intellectual property relating
+# to a hardware implementation of the functionality of the software
+# licensed hereunder.  You may use the software subject to the license
+# terms below provided that you ensure that this notice is replicated
+# unmodified and in its entirety in all distributions of the software,
+# modified or unmodified, in source code or in binary form.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met: redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer;
+# redistributions in binary form must reproduce the above copyright
+# notice, this list of conditions and the following disclaimer in the
+# documentation and/or other materials provided with the distribution;
+# neither the name of the copyright holders nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#
+# Authors: Andreas Sandberg
+
+from m5.params import *
+from m5.proxy import *
+from BaseMemProbe import BaseMemProbe
+
+class MemTraceProbe(BaseMemProbe):
+    type = 'MemTraceProbe'
+    cxx_header = "mem/probes/mem_trace.hh"
+
+    # Boolean to compress the trace or not.
+    trace_compress = Param.Bool(True, "Enable trace compression")
+
+    # packet trace output file, disabled by default
+    trace_file = Param.String("", "Packet trace output file")
+
diff --git a/src/mem/probes/SConscript b/src/mem/probes/SConscript
index 7391545fb..78423c5d6 100644
--- a/src/mem/probes/SConscript
+++ b/src/mem/probes/SConscript
@@ -44,3 +44,8 @@ Source('base.cc')
 
 SimObject('StackDistProbe.py')
 Source('stack_dist.cc')
+
+# Packet tracing requires protobuf support
+if env['HAVE_PROTOBUF']:
+    SimObject('MemTraceProbe.py')
+    Source('mem_trace.cc')
diff --git a/src/mem/probes/mem_trace.cc b/src/mem/probes/mem_trace.cc
new file mode 100644
index 000000000..6bf6f7f77
--- /dev/null
+++ b/src/mem/probes/mem_trace.cc
@@ -0,0 +1,114 @@
+/*
+ * Copyright (c) 2015 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Andreas Hansson
+ *          Andreas Sandberg
+ */
+
+#include "mem/probes/mem_trace.hh"
+
+#include "base/callback.hh"
+#include "base/output.hh"
+#include "params/MemTraceProbe.hh"
+#include "proto/packet.pb.h"
+
+MemTraceProbe::MemTraceProbe(MemTraceProbeParams *p)
+    : BaseMemProbe(p),
+      traceStream(nullptr)
+{
+    std::string filename;
+    if (p->trace_file != "") {
+        // If the trace file is not specified as an absolute path,
+        // append the current simulation output directory
+        filename = simout.resolve(p->trace_file);
+
+        const std::string suffix = ".gz";
+        // If trace_compress has been set, check the suffix. Append
+        // accordingly.
+        if (p->trace_compress &&
+            filename.compare(filename.size() - suffix.size(), suffix.size(),
+                             suffix) != 0)
+            filename = filename + suffix;
+    } else {
+        // Generate a filename from the name of the SimObject. Append .trc
+        // and .gz if we want compression enabled.
+        filename = simout.resolve(name() + ".trc" +
+                                  (p->trace_compress ? ".gz" : ""));
+    }
+
+    traceStream = new ProtoOutputStream(filename);
+
+    // 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));
+}
+
+void
+MemTraceProbe::closeStreams()
+{
+    if (traceStream != NULL)
+        delete traceStream;
+}
+
+void
+MemTraceProbe::handleRequest(const PacketPtr &pkt)
+{
+    ProtoMessage::Packet pkt_msg;
+
+    pkt_msg.set_tick(curTick());
+    pkt_msg.set_cmd(pkt->cmdToIndex());
+    pkt_msg.set_flags(pkt->req->getFlags());
+    pkt_msg.set_addr(pkt->getAddr());
+    pkt_msg.set_size(pkt->getSize());
+
+    traceStream->write(pkt_msg);
+}
+
+
+MemTraceProbe *
+MemTraceProbeParams::create()
+{
+    return new MemTraceProbe(this);
+}
diff --git a/src/mem/probes/mem_trace.hh b/src/mem/probes/mem_trace.hh
new file mode 100644
index 000000000..93c6067ae
--- /dev/null
+++ b/src/mem/probes/mem_trace.hh
@@ -0,0 +1,69 @@
+/*
+ * Copyright (c) 2015 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Andreas Sandberg
+ */
+
+#ifndef __MEM_PROBES_STACK_DIST_HH__
+#define __MEM_PROBES_STACK_DIST_HH__
+
+#include "mem/packet.hh"
+#include "mem/probes/base.hh"
+#include "proto/protoio.hh"
+
+struct MemTraceProbeParams;
+
+class MemTraceProbe : public BaseMemProbe
+{
+  public:
+    MemTraceProbe(MemTraceProbeParams *params);
+
+  protected:
+    void handleRequest(const PacketPtr &pkt) M5_ATTR_OVERRIDE;
+
+    /**
+     * Callback to flush and close all open output streams on exit. If
+     * we were calling the destructor it could be done there.
+     */
+    void closeStreams();
+
+  protected:
+
+    /** Trace output stream */
+    ProtoOutputStream *traceStream;
+};
+
+#endif //__MEM_PROBES_STACK_DIST_HH__
diff --git a/tests/configs/tgen-simple-mem.py b/tests/configs/tgen-simple-mem.py
index 8c2aa80a9..d128eb37d 100644
--- a/tests/configs/tgen-simple-mem.py
+++ b/tests/configs/tgen-simple-mem.py
@@ -56,8 +56,8 @@ system = System(cpu = cpu, physmem = SimpleMemory(),
 
 # add a communication monitor, and also trace all the packets and
 # calculate and verify stack distance
-system.monitor = CommMonitor(trace_file = "monitor.ptrc.gz",
-                             trace_enable = True)
+system.monitor = CommMonitor()
+system.monitor.trace = MemTraceProbe(trace_file = "monitor.ptrc.gz")
 system.monitor.stackdist = StackDistProbe(verify = True)
 
 # connect the traffic generator to the bus via a communication monitor