TrafficGen: Add a basic traffic generator

This patch adds a traffic generator to the code base. The generator is
aimed to be used as a black box model to create appropriate use-cases
and benchmarks for the memory system, and in particular the
interconnect and the memory controller.

The traffic generator is a master module, where the actual behaviour
is captured in a state-transition graph where each state generates
some sort of traffic. By constructing a graph it is possible to create
very elaborate scenarios from basic generators. Currencly the set of
generators include idling, linear address sweeps, random address
sequences and playback of traces (recording will be done by the
Communication Monitor in a follow-up patch). At the moment the graph
and the states are described in an ad-hoc line-based format, and in
the future this should be aligned with our used of e.g. the Google
protobufs. Similarly for the traces, the format is currently a
simplistic ad-hoc line-based format that merely serves as a starting
point.

In addition to being used as a black-box model for system components,
the traffic generator is also useful for creating test cases and
regressions for the interconnect and memory system. In future patches
we will use the traffic generator to create DRAM test cases for the
controller model.

The patch following this one adds a basic regressions which also
contains an example configuration script and trace file for playback.

1 files changed, 638 insertions, 0 deletions

diff --git a/src/cpu/testers/traffic_gen/traffic_gen.cc b/src/cpu/testers/traffic_gen/traffic_gen.cc
new file mode 100644
index 000000000..054900b20
--- /dev/null
+++ b/src/cpu/testers/traffic_gen/traffic_gen.cc
@@ -0,0 +1,638 @@
+/*
+ * Copyright (c) 2012 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: Thomas Grass
+ *          Andreas Hansson
+ *          Sascha Bischoff
+ */
+
+#include <sstream>
+
+#include "base/random.hh"
+#include "cpu/testers/traffic_gen/traffic_gen.hh"
+#include "debug/Checkpoint.hh"
+#include "debug/TrafficGen.hh"
+#include "sim/stats.hh"
+#include "sim/system.hh"
+
+using namespace std;
+
+TrafficGen::TrafficGen(const TrafficGenParams* p)
+    : MemObject(p),
+      system(p->system),
+      masterID(system->getMasterId(name())),
+      port(name() + ".port", *this),
+      stateGraph(*this, port, p->config_file, masterID),
+      updateStateGraphEvent(this)
+{
+}
+
+TrafficGen*
+TrafficGenParams::create()
+{
+    return new TrafficGen(this);
+}
+
+MasterPort&
+TrafficGen::getMasterPort(const string& if_name, int idx)
+{
+    if (if_name == "port") {
+        return port;
+    } else {
+        return MemObject::getMasterPort(if_name, idx);
+    }
+}
+
+void
+TrafficGen::init()
+{
+    if (!port.isConnected())
+        fatal("The port of %s is not connected!\n", name());
+
+    Enums::MemoryMode mode = system->getMemoryMode();
+
+    // if the system is in timing mode active the request generator
+    if (mode == Enums::timing) {
+        DPRINTF(TrafficGen, "Timing mode, activating request generator\n");
+
+        // enter initial state
+        stateGraph.enterState(stateGraph.currState);
+    } else {
+        DPRINTF(TrafficGen,
+                "Traffic generator is only active in timing mode\n");
+    }
+}
+
+void
+TrafficGen::initState()
+{
+    // when not restoring from a checkpoint, make sure we kick things off
+    if (system->getMemoryMode() == Enums::timing) {
+        Tick nextStateGraphEvent = stateGraph.nextEventTick();
+        schedule(updateStateGraphEvent, nextStateGraphEvent);
+    } else {
+        DPRINTF(TrafficGen,
+                "Traffic generator is only active in timing mode\n");
+    }
+}
+
+unsigned int
+TrafficGen::drain(Event* drain_event)
+{
+    // @todo we should also stop putting new requests in the queue and
+    // either interrupt the current state or wait for a transition
+    return port.drain(drain_event);
+}
+
+void
+TrafficGen::serialize(ostream &os)
+{
+    DPRINTF(Checkpoint, "Serializing TrafficGen\n");
+
+    // save ticks of the graph event if it is scheduled
+    Tick nextStateGraphEvent = updateStateGraphEvent.scheduled() ?
+        updateStateGraphEvent.when() : 0;
+
+    DPRINTF(TrafficGen, "Saving nextStateGraphEvent=%llu\n",
+            nextStateGraphEvent);
+
+    SERIALIZE_SCALAR(nextStateGraphEvent);
+
+    Tick nextTransitionTick = stateGraph.nextTransitionTick;
+    SERIALIZE_SCALAR(nextTransitionTick);
+
+    // @todo: also serialise the current state, figure out the best
+    // way to drain and restore
+}
+
+void
+TrafficGen::unserialize(Checkpoint* cp, const string& section)
+{
+    // restore scheduled events
+    Tick nextStateGraphEvent;
+    UNSERIALIZE_SCALAR(nextStateGraphEvent);
+    if (nextStateGraphEvent != 0) {
+        schedule(updateStateGraphEvent, nextStateGraphEvent);
+    }
+
+    Tick nextTransitionTick;
+    UNSERIALIZE_SCALAR(nextTransitionTick);
+    stateGraph.nextTransitionTick = nextTransitionTick;
+}
+
+void
+TrafficGen::updateStateGraph()
+{
+    // schedule next update event based on either the next execute
+    // tick or the next transition, which ever comes first
+    Tick nextStateGraphEvent = stateGraph.nextEventTick();
+    DPRINTF(TrafficGen, "Updating state graph, next event at %lld\n",
+            nextStateGraphEvent);
+    schedule(updateStateGraphEvent, nextStateGraphEvent);
+
+    // perform the update associated with the current update event
+    stateGraph.update();
+}
+
+void
+TrafficGen::StateGraph::parseConfig(const string& file_name,
+                                    MasterID master_id)
+{
+    // keep track of the transitions parsed to create the matrix when
+    // done
+    vector<Transition> transitions;
+
+    // open input file
+    ifstream infile;
+    infile.open(file_name.c_str(), ifstream::in);
+    if (!infile.is_open()) {
+        fatal("Traffic generator %s config file not found at %s\n",
+              owner.name(), file_name);
+    }
+
+    // read line by line and determine the action based on the first
+    // keyword
+    string keyword;
+    string line;
+
+    while (getline(infile, line).good()) {
+        // see if this line is a comment line, and if so skip it
+        if (line.find('#') != 1) {
+            // create an input stream for the tokenization
+            istringstream is(line);
+
+            // determine the keyword
+            is >> keyword;
+
+            if (keyword == "STATE") {
+                // parse the behaviour of this state
+                uint32_t id;
+                Tick duration;
+                string mode;
+
+                is >> id >> duration >> mode;
+
+                if (mode == "TRACE") {
+                    string traceFile;
+                    Addr addrOffset;
+
+                    is >> traceFile >> addrOffset;
+
+                    states[id] = new TraceGen(port, master_id, duration,
+                                              traceFile, addrOffset);
+                    DPRINTF(TrafficGen, "State: %d TraceGen\n", id);
+                } else if (mode == "IDLE") {
+                    states[id] = new IdleGen(port, master_id, duration);
+                    DPRINTF(TrafficGen, "State: %d IdleGen\n", id);
+                } else if (mode == "LINEAR" || mode == "RANDOM") {
+                    uint32_t read_percent;
+                    Addr start_addr;
+                    Addr end_addr;
+                    Addr blocksize;
+                    Tick min_period;
+                    Tick max_period;
+                    Addr data_limit;
+
+                    is >> read_percent >> start_addr >> end_addr >>
+                        blocksize >> min_period >> max_period >> data_limit;
+
+                    DPRINTF(TrafficGen, "%s, addr %x to %x, size %d,"
+                            " period %d to %d, %d%% reads\n",
+                            mode, start_addr, end_addr, blocksize, min_period,
+                            max_period, read_percent);
+
+                    if (read_percent > 100)
+                        panic("%s cannot have more than 100% reads", name());
+
+                    if (mode == "LINEAR") {
+                        states[id] = new LinearGen(port, master_id,
+                                                   duration, start_addr,
+                                                   end_addr, blocksize,
+                                                   min_period, max_period,
+                                                   read_percent, data_limit);
+                        DPRINTF(TrafficGen, "State: %d LinearGen\n", id);
+                    } else if (mode == "RANDOM") {
+                        states[id] = new RandomGen(port, master_id,
+                                                   duration, start_addr,
+                                                   end_addr, blocksize,
+                                                   min_period, max_period,
+                                                   read_percent, data_limit);
+                        DPRINTF(TrafficGen, "State: %d RandomGen\n", id);
+                    }
+                } else {
+                    fatal("%s: Unknown traffic generator mode: %s",
+                          name(), mode);
+                }
+            } else if (keyword == "TRANSITION") {
+                Transition transition;
+
+                is >> transition.from >> transition.to >> transition.p;
+
+                transitions.push_back(transition);
+
+                DPRINTF(TrafficGen, "Transition: %d -> %d\n", transition.from,
+                        transition.to);
+            } else if (keyword == "INIT") {
+                // set the initial state as the active state
+                is >> currState;
+
+                DPRINTF(TrafficGen, "Initial state: %d\n", currState);
+            }
+        }
+    }
+
+    // resize and populate state transition matrix
+    transitionMatrix.resize(transitions.size());
+    for (size_t i = 0; i < transitions.size(); i++) {
+        transitionMatrix[i].resize(transitions.size());
+    }
+
+    for (vector<Transition>::iterator t = transitions.begin();
+         t != transitions.end(); ++t) {
+        transitionMatrix[t->from][t->to] = t->p;
+    }
+
+    // ensure the egress edges do not have a probability larger than
+    // one
+    for (size_t i = 0; i < transitions.size(); i++) {
+        double sum = 0;
+        for (size_t j = 0; j < transitions.size(); j++) {
+            sum += transitionMatrix[i][j];
+        }
+
+        // avoid comparing floating point numbers
+        if (abs(sum - 1.0) > 0.001)
+            fatal("%s has transition probability != 1 for state %d\n",
+                  name(), i);
+    }
+
+    // close input file
+    infile.close();
+}
+
+void
+TrafficGen::StateGraph::update()
+{
+    // if we have reached the time for the next state transition, then
+    // perform the transition
+    if (curTick() >= nextTransitionTick) {
+        transition();
+    } else {
+        // we are still in the current state and should execute it
+        states[currState]->execute();
+    }
+}
+
+void
+TrafficGen::StateGraph::transition()
+{
+    // exit the current state
+    states[currState]->exit();
+
+    // determine next state
+    double p = random_mt.gen_real1();
+    assert(currState < transitionMatrix.size());
+    double cumulative = transitionMatrix[currState][0];
+    size_t i = 1;
+    while (p < cumulative && i != transitionMatrix[currState].size()) {
+        cumulative += transitionMatrix[currState][i];
+        ++i;
+    }
+    enterState(i);
+}
+
+void
+TrafficGen::StateGraph::enterState(uint32_t newState)
+{
+    DPRINTF(TrafficGen, "Transition to state %d\n", newState);
+
+    currState = newState;
+    nextTransitionTick += states[currState]->duration;
+    states[currState]->enter();
+}
+
+TrafficGen::StateGraph::BaseGen::BaseGen(QueuedMasterPort& _port,
+                                         MasterID master_id,
+                                         Tick _duration)
+    : port(_port), masterID(master_id), duration(_duration)
+{
+}
+
+void
+TrafficGen::StateGraph::LinearGen::enter()
+{
+    // reset the address and the data counter
+    nextAddr = startAddr;
+    dataManipulated = 0;
+
+    // this test only needs to happen once, but cannot be performed
+    // before init() is called and the ports are connected
+    if (port.deviceBlockSize() && blocksize > port.deviceBlockSize())
+        fatal("TrafficGen %s block size (%d) is larger than port"
+              " block size (%d)\n", blocksize, port.deviceBlockSize());
+
+}
+
+void
+TrafficGen::StateGraph::LinearGen::execute()
+{
+    // choose if we generate a read or a write here
+    bool isRead = random_mt.random<uint8_t>(0, 100) < readPercent;
+
+    if (readPercent == 0)
+        assert(!isRead);
+
+    DPRINTF(TrafficGen, "LinearGen::execute: %c to addr %x, size %d\n",
+            isRead ? 'r' : 'w', nextAddr, blocksize);
+
+    // Create new request
+    Request::Flags flags;
+    Request *req = new Request(nextAddr, blocksize, flags, masterID);
+
+    PacketPtr pkt = new Packet(req, isRead ? MemCmd::ReadReq :
+                               MemCmd::WriteReq);
+
+    uint8_t* pkt_data = new uint8_t[req->getSize()];
+    pkt->dataDynamicArray(pkt_data);
+
+    if (!isRead) {
+        memset(pkt_data, 0xA, req->getSize());
+    }
+
+    port.schedTimingReq(pkt, curTick());
+
+    // increment the address
+    nextAddr += blocksize;
+
+    // Add the amount of data manipulated to the total
+    dataManipulated += blocksize;
+}
+
+Tick
+TrafficGen::StateGraph::LinearGen::nextExecuteTick()
+{
+    // If we have reached the end of the address space, reset the
+    // address to the start of the range
+    if (nextAddr + blocksize > endAddr) {
+        DPRINTF(TrafficGen, "Wrapping address to the start of "
+                "the range\n");
+        nextAddr = startAddr;
+    }
+
+    // Check to see if we have reached the data limit. If dataLimit is
+    // zero we do not have a data limit and therefore we will keep
+    // generating requests for the entire residency in this state.
+    if (dataLimit && dataManipulated >= dataLimit) {
+        DPRINTF(TrafficGen, "Data limit for LinearGen reached.\n");
+        // there are no more requests, therefore return MaxTick
+        return MaxTick;
+    } else {
+        // return the time when the next request should take place
+        return curTick() + random_mt.random<Tick>(minPeriod, maxPeriod);
+    }
+}
+
+void
+TrafficGen::StateGraph::RandomGen::enter()
+{
+    // reset the counter to zero
+    dataManipulated = 0;
+
+    // this test only needs to happen once, but cannot be performed
+    // before init() is called and the ports are connected
+    if (port.deviceBlockSize() && blocksize > port.deviceBlockSize())
+        fatal("TrafficGen %s block size (%d) is larger than port"
+              " block size (%d)\n", name(), blocksize, port.deviceBlockSize());
+}
+
+void
+TrafficGen::StateGraph::RandomGen::execute()
+{
+    // choose if we generate a read or a write here
+    bool isRead = random_mt.random<uint8_t>(0, 100) < readPercent;
+
+    if (readPercent == 0)
+        assert(!isRead);
+
+    // address of the request
+    Addr addr = random_mt.random<Addr>(startAddr, endAddr - 1);
+
+    // round down to start address of block
+    addr -= addr % blocksize;
+
+    DPRINTF(TrafficGen, "RandomGen::execute: %c to addr %x, size %d\n",
+            isRead ? 'r' : 'w', addr, blocksize);
+
+    // create new request packet
+    Request::Flags flags;
+    Request *req = new Request(addr, blocksize, flags, masterID);
+
+    PacketPtr pkt = new Packet(req, isRead ? MemCmd::ReadReq :
+                               MemCmd::WriteReq);
+
+    uint8_t* pkt_data = new uint8_t[req->getSize()];
+    pkt->dataDynamicArray(pkt_data);
+
+    if (!isRead) {
+        memset(pkt_data, 0xA, req->getSize());
+    }
+
+    port.schedTimingReq(pkt, curTick());
+
+    // Add the amount of data manipulated to the total
+    dataManipulated += blocksize;
+}
+
+Tick
+TrafficGen::StateGraph::RandomGen::nextExecuteTick()
+{
+    // Check to see if we have reached the data limit. If dataLimit is
+    // zero we do not have a data limit and therefore we will keep
+    // generating requests for the entire residency in this state.
+    if (dataLimit && dataManipulated >= dataLimit)
+    {
+        DPRINTF(TrafficGen, "Data limit for RandomGen reached.\n");
+        // No more requests. Return MaxTick.
+        return MaxTick;
+    } else {
+        // Return the time when the next request should take place.
+        return curTick() + random_mt.random<Tick>(minPeriod, maxPeriod);
+    }
+}
+
+Tick
+TrafficGen::StateGraph::TraceGen::nextExecuteTick() {
+    // We need to look at the next line to calculate the next time an
+    // event occurs, or potentially return MaxTick to signal that
+    // nothing has to be done.
+    string buffer;
+    if (!traceComplete && trace.good()){
+        getline(trace, buffer);
+        DPRINTF(TrafficGen, "Input trace: %s\n", buffer);
+    } else {
+        // We are at the end of the file, thus we have no more data in
+        // the trace Return MaxTick to signal that there will be no
+        // more transactions in this active period for the state.
+        return MaxTick;
+    }
+
+    //Reset the nextElement to the default values
+    currElement = nextElement;
+    nextElement.clear();
+
+    // Check that we have something to process. This assume no EOF at
+    // the end of the line.
+    if (buffer.size() > 0 && !trace.eof()) {
+        istringstream iss(buffer);
+
+        char rOrW, ch;
+        iss >> rOrW;
+        iss >> ch; assert(ch == ',');
+        iss >> nextElement.addr;
+        iss >> ch; assert(ch == ',');
+        iss >> nextElement.blocksize;
+        iss >> ch; assert(ch == ',');
+        iss >> nextElement.tick;
+
+        if (rOrW == 'r') {
+            nextElement.cmd = MemCmd::ReadReq;
+        } else if (rOrW == 'w') {
+            nextElement.cmd = MemCmd::WriteReq;
+        } else {
+            fatal("Incorrect trace file format!\n");
+        }
+    }
+
+    // Check that we have a valid request
+    if (!nextElement.isValid()) {
+        // If it is not valid, assume that we have reached the end of
+        // the trace.  Even if this is not the case, we do not know
+        // what to do with the request as it makes no sense.
+        if (trace.good()) {
+            // Trace is good, therefore we are not at the end of the
+            // file. This means that the input trace cannot be read
+            // correctly or it contains data that makes no sense.
+            warn("Unable to read the trace file format\n");
+            warn("%s", buffer);
+        }
+
+        traceComplete = true;
+        return MaxTick;
+    }
+
+    DPRINTF(TrafficGen, "currElement: %c addr %d size %d tick %d (%d)\n",
+            currElement.cmd.isRead() ? 'r' : 'w',
+            currElement.addr,
+            currElement.blocksize,
+            currElement.tick + tickOffset,
+            currElement.tick);
+
+    DPRINTF(TrafficGen, "nextElement: %c addr %d size %d tick %d (%d)\n",
+            nextElement.cmd.isRead() ? 'r' : 'w',
+            nextElement.addr,
+            nextElement.blocksize,
+            nextElement.tick + tickOffset,
+            nextElement.tick);
+
+    return tickOffset + nextElement.tick;
+}
+
+void
+TrafficGen::StateGraph::TraceGen::enter() {
+    // update the trace offset to the time where the state was entered.
+    tickOffset = curTick();
+
+    // seek to the start of the input trace file
+    trace.seekg(0, ifstream::beg);
+    trace.clear();
+
+    // clear everything
+    nextElement.clear();
+    currElement.clear();
+
+    traceComplete = false;
+}
+
+void
+TrafficGen::StateGraph::TraceGen::execute() {
+    // it is the responsibility of nextExecuteTick to prevent the
+    // state graph from executing the state if it should not
+    assert(currElement.isValid());
+
+    DPRINTF(TrafficGen, "TraceGen::execute: %c %d %d %d\n",
+            currElement.cmd.isRead() ? 'r' : 'w',
+            currElement.addr,
+            currElement.blocksize,
+            currElement.tick);
+
+    Request::Flags flags;
+    Request *req = new Request(currElement.addr + addrOffset,
+                               currElement.blocksize, flags, masterID);
+
+    PacketPtr pkt = new Packet(req, currElement.cmd);
+
+    uint8_t* pkt_data = new uint8_t[req->getSize()];
+    pkt->dataDynamicArray(pkt_data);
+
+    if (currElement.cmd.isWrite()) {
+        memset(pkt_data, 0xA, req->getSize());
+    }
+
+    port.schedTimingReq(pkt, curTick());
+}
+
+void
+TrafficGen::StateGraph::TraceGen::exit() {
+    // Check if we reached the end of the trace file. If we did not
+    // then we want to generate a warning stating that not the entire
+    // trace was played.
+    if (!trace.eof()) {
+        warn("Trace player %s was unable to replay the entire trace!\n",
+             name());
+    }
+
+    // clear any previous error flags for the input trace file
+    trace.clear();
+}
+
+bool
+TrafficGen::TrafficGenPort::recvTimingResp(PacketPtr pkt)
+{
+    delete pkt->req;
+    delete pkt;
+
+    return true;
+}