dist_etherlink.cc

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 * Copyright (c) 2015 ARM Limited
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 * this software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * Authors: Gabor Dozsa
 */

/* @file
 * Device module for a full duplex ethernet link for dist gem5 simulations.
 */

#include "dev/net/dist_etherlink.hh"

#include <arpa/inet.h>
#include <sys/socket.h>
#include <unistd.h>

#include <cmath>
#include <deque>
#include <string>
#include <vector>

#include "base/random.hh"
#include "base/trace.hh"
#include "debug/DistEthernet.hh"
#include "debug/DistEthernetPkt.hh"
#include "debug/EthernetData.hh"
#include "dev/net/dist_iface.hh"
#include "dev/net/etherdump.hh"
#include "dev/net/etherint.hh"
#include "dev/net/etherlink.hh"
#include "dev/net/etherpkt.hh"
#include "dev/net/tcp_iface.hh"
#include "params/EtherLink.hh"
#include "sim/core.hh"
#include "sim/serialize.hh"
#include "sim/system.hh"

using namespace std;

DistEtherLink::DistEtherLink(const Params *p)
    : SimObject(p), linkDelay(p->delay)
{
    DPRINTF(DistEthernet,"DistEtherLink::DistEtherLink() "
            "link delay:%llu ticksPerByte:%f\n", p->delay, p->speed);

    txLink = new TxLink(name() + ".link0", this, p->speed, p->delay_var,
                        p->dump);
    rxLink = new RxLink(name() + ".link1", this, p->delay, p->dump);

    Tick sync_repeat;
    if (p->sync_repeat != 0) {
        if (p->sync_repeat != p->delay)
            warn("DistEtherLink(): sync_repeat is %lu and linkdelay is %lu",
                 p->sync_repeat, p->delay);
        sync_repeat = p->sync_repeat;
    } else {
        sync_repeat = p->delay;
    }

    // create the dist (TCP) interface to talk to the peer gem5 processes.
    distIface = new TCPIface(p->server_name, p->server_port,
                             p->dist_rank, p->dist_size,
                             p->sync_start, sync_repeat, this,
                             p->dist_sync_on_pseudo_op, p->is_switch,
                             p->num_nodes);

    localIface = new LocalIface(name() + ".int0", txLink, rxLink, distIface);
}

DistEtherLink::~DistEtherLink()
{
    delete txLink;
    delete rxLink;
    delete localIface;
    delete distIface;
}

Port &
DistEtherLink::getPort(const std::string &if_name, PortID idx)
{
    if (if_name == "int0")
        return *localIface;
    return SimObject::getPort(if_name, idx);
}

void
DistEtherLink::serialize(CheckpointOut &cp) const
{
    distIface->serializeSection(cp, "distIface");
    txLink->serializeSection(cp, "txLink");
    rxLink->serializeSection(cp, "rxLink");
}

void
DistEtherLink::unserialize(CheckpointIn &cp)
{
    distIface->unserializeSection(cp, "distIface");
    txLink->unserializeSection(cp, "txLink");
    rxLink->unserializeSection(cp, "rxLink");
}

void
DistEtherLink::init()
{
    DPRINTF(DistEthernet,"DistEtherLink::init() called\n");
    distIface->init(rxLink->doneEvent(), linkDelay);
}

void
DistEtherLink::startup()
{
    DPRINTF(DistEthernet,"DistEtherLink::startup() called\n");
    distIface->startup();
}

void
DistEtherLink::RxLink::setDistInt(DistIface *m)
{
    assert(!distIface);
    distIface = m;
}

void
DistEtherLink::RxLink::rxDone()
{
    assert(!busy());

    // retrieve the packet that triggered the receive done event
    packet = distIface->packetIn();

    if (dump)
        dump->dump(packet);

    DPRINTF(DistEthernetPkt, "DistEtherLink::DistLink::rxDone() "
            "packet received: len=%d\n", packet->length);
    DDUMP(EthernetData, packet->data, packet->length);

    localIface->sendPacket(packet);

    packet = nullptr;
}

void
DistEtherLink::TxLink::txDone()
{
    if (dump)
        dump->dump(packet);

    packet = nullptr;
    assert(!busy());

    localIface->sendDone();
}

bool
DistEtherLink::TxLink::transmit(EthPacketPtr pkt)
{
    if (busy()) {
        DPRINTF(DistEthernet, "packet not sent, link busy\n");
        return false;
    }

    packet = pkt;
    Tick delay = (Tick)ceil(((double)pkt->simLength * ticksPerByte) + 1.0);
    if (delayVar != 0)
        delay += random_mt.random<Tick>(0, delayVar);

    // send the packet to the peers
    assert(distIface);
    distIface->packetOut(pkt, delay);

    // schedule the send done event
    parent->schedule(doneEvent, curTick() + delay);

    return true;
}

void
DistEtherLink::Link::serialize(CheckpointOut &cp) const
{
    bool packet_exists = (packet != nullptr);
    SERIALIZE_SCALAR(packet_exists);
    if (packet_exists)
        packet->serialize("packet", cp);

    bool event_scheduled = event->scheduled();
    SERIALIZE_SCALAR(event_scheduled);
    if (event_scheduled) {
        Tick event_time = event->when();
        SERIALIZE_SCALAR(event_time);
    }
}

void
DistEtherLink::Link::unserialize(CheckpointIn &cp)
{
    bool packet_exists;
    UNSERIALIZE_SCALAR(packet_exists);
    if (packet_exists) {
        packet = make_shared<EthPacketData>();
        packet->unserialize("packet", cp);
    }

    bool event_scheduled;
    UNSERIALIZE_SCALAR(event_scheduled);
    if (event_scheduled) {
        Tick event_time;
        UNSERIALIZE_SCALAR(event_time);
        parent->schedule(*event, event_time);
    }
}

DistEtherLink::LocalIface::LocalIface(const std::string &name,
                                       TxLink *tx,
                                       RxLink *rx,
                                       DistIface *m) :
    EtherInt(name), txLink(tx)
{
    tx->setLocalInt(this);
    rx->setLocalInt(this);
    tx->setDistInt(m);
    rx->setDistInt(m);
}

DistEtherLink *
DistEtherLinkParams::create()
{
    return new DistEtherLink(this);
}