Add the capability to read and write memory trace files. Currently is cycle accurate for a single thread FullCPU.

--HG--
extra : convert_revision : f8fe545313eb307cc6f5ff2c23894cc9870b1d5b

6 files changed, 597 insertions, 0 deletions

diff --git a/cpu/trace/reader/m5_reader.cc b/cpu/trace/reader/m5_reader.cc
new file mode 100644
index 000000000..d6ec7be50
--- /dev/null
+++ b/cpu/trace/reader/m5_reader.cc
@@ -0,0 +1,93 @@
+/*
+ * Copyright (c) 2003-2004 The Regents of The University of Michigan
+ * All rights reserved.
+ *
+ * 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.
+ */
+
+/**
+ * @file
+ * Declaration of a memory trace reader for a M5 memory trace.
+ */
+
+#include "cpu/trace/reader/m5_reader.hh"
+#include "mem/trace/m5_format.hh"
+#include "mem/mem_cmd.hh"
+#include "sim/builder.hh"
+
+using namespace std;
+
+M5Reader::M5Reader(const string &name, const string &filename)
+    : MemTraceReader(name)
+{
+    traceFile.open(filename.c_str(), ios::binary);
+}
+
+Tick
+M5Reader::getNextReq(MemReqPtr &req)
+{
+    M5Format ref;
+
+    MemReqPtr tmp_req;
+    // Need to read EOF char before eof() will return true.
+    traceFile.read((char*) &ref, sizeof(ref));
+    if (!traceFile.eof()) {
+        //traceFile.read((char*) &ref, sizeof(ref));
+        int gcount = traceFile.gcount();
+        assert(gcount != 0 || traceFile.eof());
+        assert(gcount == sizeof(ref));
+        assert(ref.cmd < 12);
+        tmp_req = new MemReq();
+        tmp_req->paddr = ref.paddr;
+        tmp_req->asid = ref.asid;
+        tmp_req->cmd = (MemCmdEnum)ref.cmd;
+        tmp_req->size = ref.size;
+        tmp_req->dest = ref.dest;
+    } else {
+        ref.cycle = 0;
+    }
+    req = tmp_req;
+    return ref.cycle;
+}
+
+BEGIN_DECLARE_SIM_OBJECT_PARAMS(M5Reader)
+
+    Param<string> filename;
+
+END_DECLARE_SIM_OBJECT_PARAMS(M5Reader)
+
+
+BEGIN_INIT_SIM_OBJECT_PARAMS(M5Reader)
+
+    INIT_PARAM(filename, "trace file")
+
+END_INIT_SIM_OBJECT_PARAMS(M5Reader)
+
+
+CREATE_SIM_OBJECT(M5Reader)
+{
+    return new M5Reader(getInstanceName(), filename);
+}
+
+REGISTER_SIM_OBJECT("M5Reader", M5Reader)
diff --git a/cpu/trace/reader/m5_reader.hh b/cpu/trace/reader/m5_reader.hh
new file mode 100644
index 000000000..d78787461
--- /dev/null
+++ b/cpu/trace/reader/m5_reader.hh
@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 2003-2004 The Regents of The University of Michigan
+ * All rights reserved.
+ *
+ * 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.
+ */
+
+/**
+ * @file
+ * Definition of a memory trace reader for a M5 memory trace.
+ */
+
+#ifndef __M5_READER_HH__
+#define __M5_READER_HH__
+
+#include <fstream>
+
+#include "cpu/trace/reader/mem_trace_reader.hh"
+
+/**
+ * A memory trace reader for an M5 memory trace. @sa M5Writer.
+ */
+class M5Reader : public MemTraceReader
+{
+    /** The traceFile. */
+    std::ifstream traceFile;
+
+    std::string fn;
+
+  public:
+    /**
+     * Construct an M5 memory trace reader.
+     */
+    M5Reader(const std::string &name, const std::string &filename);
+
+
+    /**
+     * Read the next request from the trace. Returns the request in the
+     * provided MemReqPtr and the cycle of the request in the return value.
+     * @param req Return the next request from the trace.
+     * @return The cycle the reference was started.
+     */
+    virtual Tick getNextReq(MemReqPtr &req);
+};
+
+#endif // __M5_READER_HH__
diff --git a/cpu/trace/reader/mem_trace_reader.cc b/cpu/trace/reader/mem_trace_reader.cc
new file mode 100644
index 000000000..c6fc53f51
--- /dev/null
+++ b/cpu/trace/reader/mem_trace_reader.cc
@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2003-2004 The Regents of The University of Michigan
+ * All rights reserved.
+ *
+ * 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.
+ */
+
+/**
+ * @file
+ * SimObject Declaration of pure virtual MemTraceReader class.
+ */
+
+#include "cpu/trace/reader/mem_trace_reader.hh"
+#include "sim/param.hh"
+
+DEFINE_SIM_OBJECT_CLASS_NAME("MemTraceReader", MemTraceReader);
diff --git a/cpu/trace/reader/mem_trace_reader.hh b/cpu/trace/reader/mem_trace_reader.hh
new file mode 100644
index 000000000..5da99a498
--- /dev/null
+++ b/cpu/trace/reader/mem_trace_reader.hh
@@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2003-2004 The Regents of The University of Michigan
+ * All rights reserved.
+ *
+ * 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.
+ */
+
+/**
+ * Definitions for a pure virtual interface to a memory trace reader.
+ */
+
+#ifndef __MEM_TRACE_READER_HH__
+#define __MEM_TRACE_READER_HH__
+
+#include "sim/sim_object.hh"
+#include "mem/mem_req.hh" // For MemReqPtr
+
+/**
+ * Pure virtual base class for memory trace readers.
+ */
+class MemTraceReader : public SimObject
+{
+  public:
+    /** Construct this MemoryTrace reader. */
+    MemTraceReader(const std::string &name) : SimObject(name) {}
+
+    /**
+     * Read the next request from the trace. Returns the request in the
+     * provided MemReqPtr and the cycle of the request in the return value.
+     * @param req Return the next request from the trace.
+     * @return The cycle of the request, 0 if none in trace.
+     */
+    virtual Tick getNextReq(MemReqPtr &req) = 0;
+};
+
+#endif //__MEM_TRACE_READER_HH__
diff --git a/cpu/trace/trace_cpu.cc b/cpu/trace/trace_cpu.cc
new file mode 100644
index 000000000..6fdc32034
--- /dev/null
+++ b/cpu/trace/trace_cpu.cc
@@ -0,0 +1,192 @@
+/*
+ * Copyright (c) 2003 The Regents of The University of Michigan
+ * All rights reserved.
+ *
+ * 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.
+ */
+
+/**
+ * @file
+ * Declaration of a memory trace CPU object. Uses a memory trace to drive the
+ * provided memory hierarchy.
+ */
+
+#include <algorithm> // For min
+
+#include "cpu/trace/trace_cpu.hh"
+#include "cpu/trace/reader/mem_trace_reader.hh"
+#include "mem/base_mem.hh" // For PARAM constructor
+#include "mem/mem_interface.hh"
+#include "sim/builder.hh"
+#include "sim/sim_events.hh"
+
+using namespace std;
+
+TraceCPU::TraceCPU(const string &name,
+                   MemInterface *icache_interface,
+                   MemInterface *dcache_interface,
+                   MemTraceReader *inst_trace,
+                   MemTraceReader *data_trace,
+                   int icache_ports,
+                   int dcache_ports)
+    : BaseCPU(name, 1), icacheInterface(icache_interface),
+      dcacheInterface(dcache_interface), instTrace(inst_trace),
+      dataTrace(data_trace), icachePorts(icache_ports),
+      dcachePorts(dcache_ports), outstandingRequests(0), tickEvent(this)
+{
+    if (instTrace) {
+        assert(icacheInterface);
+        nextInstCycle = instTrace->getNextReq(nextInstReq);
+    }
+    if (dataTrace) {
+        assert(dcacheInterface);
+        nextDataCycle = dataTrace->getNextReq(nextDataReq);
+    }
+    tickEvent.schedule(0);
+}
+
+void
+TraceCPU::tick()
+{
+    assert(outstandingRequests >= 0);
+    assert(outstandingRequests < 1000);
+    int instReqs = 0;
+    int dataReqs = 0;
+
+    // Do data first to match tracing with FullCPU dumps
+
+    while (nextDataReq && (dataReqs < dcachePorts) &&
+           curTick >= nextDataCycle) {
+        if (dcacheInterface->isBlocked())
+            break;
+
+        ++outstandingRequests;
+        ++dataReqs;
+        nextDataReq->time = curTick;
+        nextDataReq->completionEvent =
+            new TraceCompleteEvent(nextDataReq, this);
+        dcacheInterface->access(nextDataReq);
+        nextDataCycle = dataTrace->getNextReq(nextDataReq);
+    }
+
+    while (nextInstReq && (instReqs < icachePorts) &&
+           curTick >= nextInstCycle) {
+        if (icacheInterface->isBlocked())
+            break;
+
+        nextInstReq->time = curTick;
+        if (nextInstReq->cmd == Squash) {
+            icacheInterface->squash(nextInstReq->asid);
+        } else {
+            ++outstandingRequests;
+            ++instReqs;
+            nextInstReq->completionEvent =
+                new TraceCompleteEvent(nextInstReq, this);
+            icacheInterface->access(nextInstReq);
+        }
+        nextInstCycle = instTrace->getNextReq(nextInstReq);
+    }
+
+    if (!nextInstReq && !nextDataReq) {
+        // No more requests to send. Finish trailing events and exit.
+        if (mainEventQueue.empty()) {
+            new SimExitEvent("Finshed Memory Trace");
+        } else {
+            tickEvent.schedule(mainEventQueue.nextEventTime() + 1);
+        }
+    } else {
+        tickEvent.schedule(max(curTick + 1,
+                               min(nextInstCycle, nextDataCycle)));
+    }
+}
+
+void
+TraceCPU::completeRequest(MemReqPtr& req)
+{
+    --outstandingRequests;
+}
+
+void
+TraceCompleteEvent::process()
+{
+    tester->completeRequest(req);
+}
+
+const char *
+TraceCompleteEvent::description()
+{
+    return "trace access complete";
+}
+
+TraceCPU::TickEvent::TickEvent(TraceCPU *c)
+    : Event(&mainEventQueue, CPU_Tick_Pri), cpu(c)
+{
+}
+
+void
+TraceCPU::TickEvent::process()
+{
+    cpu->tick();
+}
+
+const char *
+TraceCPU::TickEvent::description()
+{
+    return "TraceCPU tick event";
+}
+
+
+
+BEGIN_DECLARE_SIM_OBJECT_PARAMS(TraceCPU)
+
+    SimObjectParam<BaseMem *> icache;
+    SimObjectParam<BaseMem *> dcache;
+    SimObjectParam<MemTraceReader *> inst_trace;
+    SimObjectParam<MemTraceReader *> data_trace;
+    Param<int> inst_ports;
+    Param<int> data_ports;
+
+END_DECLARE_SIM_OBJECT_PARAMS(TraceCPU)
+
+BEGIN_INIT_SIM_OBJECT_PARAMS(TraceCPU)
+
+    INIT_PARAM_DFLT(icache, "instruction cache", NULL),
+    INIT_PARAM_DFLT(dcache, "data cache", NULL),
+    INIT_PARAM_DFLT(inst_trace, "instruction trace", NULL),
+    INIT_PARAM_DFLT(data_trace, "data trace", NULL),
+    INIT_PARAM_DFLT(inst_ports, "instruction cache read ports", 4),
+    INIT_PARAM_DFLT(data_ports, "data cache read/write ports", 4)
+
+END_INIT_SIM_OBJECT_PARAMS(TraceCPU)
+
+CREATE_SIM_OBJECT(TraceCPU)
+{
+    return new TraceCPU(getInstanceName(),
+                        (icache) ? icache->getInterface() : NULL,
+                        (dcache) ? dcache->getInterface() : NULL,
+                        inst_trace, data_trace, inst_ports, data_ports);
+}
+
+REGISTER_SIM_OBJECT("TraceCPU", TraceCPU)
+
diff --git a/cpu/trace/trace_cpu.hh b/cpu/trace/trace_cpu.hh
new file mode 100644
index 000000000..13a204f4e
--- /dev/null
+++ b/cpu/trace/trace_cpu.hh
@@ -0,0 +1,151 @@
+/*
+ * Copyright (c) 2003 The Regents of The University of Michigan
+ * All rights reserved.
+ *
+ * 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.
+ */
+
+/**
+ * @file
+ * Declaration of a memory trace CPU object. Uses a memory trace to drive the
+ * provided memory hierarchy.
+ */
+
+#ifndef __TRACE_CPU_HH__
+#define __TRACE_CPU_HH__
+
+#include <string>
+
+#include "cpu/base_cpu.hh"
+#include "mem/mem_req.hh" // for MemReqPtr
+#include "sim/eventq.hh" // for Event
+
+// Forward declaration.
+class MemInterface;
+class MemTraceReader;
+
+/**
+ * A cpu object for running memory traces through a memory hierarchy.
+ */
+class TraceCPU : public BaseCPU
+{
+    /** Interface for instruction trace requests, if any. */
+    MemInterface *icacheInterface;
+    /** Interface for data trace requests, if any. */
+    MemInterface *dcacheInterface;
+
+    /** Instruction reference trace. */
+    MemTraceReader *instTrace;
+    /** Data reference trace. */
+    MemTraceReader *dataTrace;
+
+    /** Number of Icache read ports. */
+    int icachePorts;
+    /** Number of Dcache read/write ports. */
+    int dcachePorts;
+
+    /** Number of outstanding requests. */
+    int outstandingRequests;
+
+    /** Cycle of the next instruction request, 0 if not available. */
+    Tick nextInstCycle;
+    /** Cycle of the next data request, 0 if not available. */
+    Tick nextDataCycle;
+
+    /** Next instruction request. */
+    MemReqPtr nextInstReq;
+    /** Next data request. */
+    MemReqPtr nextDataReq;
+
+    /**
+     * Event to call the TraceCPU::tick
+     */
+    class TickEvent : public Event
+    {
+      private:
+        /** The associated CPU */
+        TraceCPU *cpu;
+
+      public:
+        /**
+         * Construct this event;
+         */
+        TickEvent(TraceCPU *c);
+
+        /**
+         * Call the tick function.
+         */
+        void process();
+
+        /**
+         * Return a string description of this event.
+         */
+        const char *description();
+    };
+
+    TickEvent tickEvent;
+
+  public:
+    /**
+     * Construct a TraceCPU object.
+     */
+    TraceCPU(const std::string &name,
+             MemInterface *icache_interface,
+             MemInterface *dcache_interface,
+             MemTraceReader *inst_trace,
+             MemTraceReader *data_trace,
+             int icache_ports,
+             int dcache_ports);
+
+    /**
+     * Perform all the accesses for one cycle.
+     */
+    void tick();
+
+    /**
+     * Handle a completed memory request.
+     */
+    void completeRequest(MemReqPtr &req);
+};
+
+class TraceCompleteEvent : public Event
+{
+    MemReqPtr req;
+    TraceCPU *tester;
+
+  public:
+
+    TraceCompleteEvent(MemReqPtr &_req, TraceCPU *_tester)
+        : Event(&mainEventQueue), req(_req), tester(_tester)
+    {
+        setFlags(AutoDelete);
+    }
+
+    void process();
+
+    virtual const char *description();
+};
+
+#endif //__TRACE_CPU_HH__
+