From 3c608bf76535dc1f08a9563b417b5c6fadeab3ff Mon Sep 17 00:00:00 2001 From: Ali Saidi Date: Wed, 9 May 2007 18:20:24 -0400 Subject: add a backoff algorithm when nacks are received by devices add seperate response buffers and request queue sizes in bus bridge add delay to respond to a nack in the bus bridge src/dev/i8254xGBe.cc: src/dev/ide_ctrl.cc: src/dev/ns_gige.cc: src/dev/pcidev.hh: src/dev/sinic.cc: add backoff delay parameters src/dev/io_device.cc: src/dev/io_device.hh: add a backoff algorithm when nacks are received. src/mem/bridge.cc: src/mem/bridge.hh: add seperate response buffers and request queue sizes add a new parameters to specify how long before a nack in ready to go after a packet that needs to be nacked is received src/mem/cache/cache_impl.hh: assert on the src/mem/tport.cc: add a friendly assert to make sure the packet was inserted into the list --HG-- extra : convert_revision : 3595ad932015a4ce2bb72772da7850ad91bd09b1 --- src/mem/bridge.cc | 118 ++++++++++++++++++++++++++++++++++++++---------------- 1 file changed, 84 insertions(+), 34 deletions(-) (limited to 'src/mem/bridge.cc') diff --git a/src/mem/bridge.cc b/src/mem/bridge.cc index e7d52b178..e89473be3 100644 --- a/src/mem/bridge.cc +++ b/src/mem/bridge.cc @@ -43,22 +43,22 @@ Bridge::BridgePort::BridgePort(const std::string &_name, Bridge *_bridge, BridgePort *_otherPort, - int _delay, int _queueLimit, - bool fix_partial_write) + int _delay, int _nack_delay, int _req_limit, + int _resp_limit, bool fix_partial_write) : Port(_name), bridge(_bridge), otherPort(_otherPort), - delay(_delay), fixPartialWrite(fix_partial_write), - outstandingResponses(0), queuedRequests(0), - queueLimit(_queueLimit), sendEvent(this) + delay(_delay), nackDelay(_nack_delay), fixPartialWrite(fix_partial_write), + outstandingResponses(0), queuedRequests(0), inRetry(false), + reqQueueLimit(_req_limit), respQueueLimit(_resp_limit), sendEvent(this) { } -Bridge::Bridge(const std::string &n, int qsa, int qsb, - Tick _delay, int write_ack, bool fix_partial_write_a, - bool fix_partial_write_b) - : MemObject(n), - portA(n + "-portA", this, &portB, _delay, qsa, fix_partial_write_a), - portB(n + "-portB", this, &portA, _delay, qsa, fix_partial_write_b), - ackWrites(write_ack) +Bridge::Bridge(Params *p) + : MemObject(p->name), + portA(p->name + "-portA", this, &portB, p->delay, p->nack_delay, + p->req_size_a, p->resp_size_a, p->fix_partial_write_a), + portB(p->name + "-portB", this, &portA, p->delay, p->nack_delay, + p->req_size_b, p->resp_size_b, p->fix_partial_write_b), + ackWrites(p->write_ack), _params(p) { if (ackWrites) panic("No support for acknowledging writes\n"); @@ -94,11 +94,17 @@ Bridge::init() } bool -Bridge::BridgePort::queueFull() +Bridge::BridgePort::respQueueFull() { - // use >= here because sendQueue could get larger because of - // nacks getting inserted - return queuedRequests + outstandingResponses >= queueLimit; + assert(outstandingResponses >= 0 && outstandingResponses <= respQueueLimit); + return outstandingResponses >= respQueueLimit; +} + +bool +Bridge::BridgePort::reqQueueFull() +{ + assert(queuedRequests >= 0 && queuedRequests <= reqQueueLimit); + return queuedRequests >= reqQueueLimit; } /** Function called by the port when the bus is receiving a Timing @@ -113,14 +119,14 @@ Bridge::BridgePort::recvTiming(PacketPtr pkt) DPRINTF(BusBridge, "recvTiming: src %d dest %d addr 0x%x\n", pkt->getSrc(), pkt->getDest(), pkt->getAddr()); - if (pkt->isRequest() && otherPort->queueFull()) { + if (pkt->isRequest() && otherPort->reqQueueFull()) { DPRINTF(BusBridge, "Remote queue full, nacking\n"); nackRequest(pkt); return true; } if (pkt->needsResponse() && pkt->result != Packet::Nacked) - if (queueFull()) { + if (respQueueFull()) { DPRINTF(BusBridge, "Local queue full, no space for response, nacking\n"); DPRINTF(BusBridge, "queue size: %d outreq: %d outstanding resp: %d\n", sendQueue.size(), queuedRequests, outstandingResponses); @@ -144,12 +150,41 @@ Bridge::BridgePort::nackRequest(PacketPtr pkt) pkt->setDest(pkt->getSrc()); //put it on the list to send - Tick readyTime = curTick + delay; + Tick readyTime = curTick + nackDelay; PacketBuffer *buf = new PacketBuffer(pkt, readyTime, true); + + // nothing on the list, add it and we're done if (sendQueue.empty()) { + assert(!sendEvent.scheduled()); sendEvent.schedule(readyTime); + sendQueue.push_back(buf); + return; } - sendQueue.push_back(buf); + + assert(sendEvent.scheduled() || inRetry); + + // does it go at the end? + if (readyTime >= sendQueue.back()->ready) { + sendQueue.push_back(buf); + return; + } + + // ok, somewhere in the middle, fun + std::list::iterator i = sendQueue.begin(); + std::list::iterator end = sendQueue.end(); + std::list::iterator begin = sendQueue.begin(); + bool done = false; + + while (i != end && !done) { + if (readyTime < (*i)->ready) { + if (i == begin) + sendEvent.reschedule(readyTime); + sendQueue.insert(i,buf); + done = true; + } + i++; + } + assert(done); } @@ -199,7 +234,6 @@ Bridge::BridgePort::trySend() { assert(!sendQueue.empty()); - bool was_full = queueFull(); int pbs = peerBlockSize(); PacketBuffer *buf = sendQueue.front(); @@ -245,15 +279,10 @@ Bridge::BridgePort::trySend() DPRINTF(BusBridge, "Scheduling next send\n"); sendEvent.schedule(std::max(buf->ready, curTick + 1)); } - // Let things start sending again - if (was_full && !queueFull()) { - DPRINTF(BusBridge, "Queue was full, sending retry\n"); - otherPort->sendRetry(); - } - } else { DPRINTF(BusBridge, " unsuccessful\n"); buf->undoPartialWriteFix(); + inRetry = true; } DPRINTF(BusBridge, "trySend: queue size: %d outreq: %d outstanding resp: %d\n", sendQueue.size(), queuedRequests, outstandingResponses); @@ -263,7 +292,12 @@ Bridge::BridgePort::trySend() void Bridge::BridgePort::recvRetry() { - trySend(); + inRetry = false; + Tick nextReady = sendQueue.front()->ready; + if (nextReady <= curTick) + trySend(); + else + sendEvent.schedule(nextReady); } /** Function called by the port when the bus is receiving a Atomic @@ -309,9 +343,12 @@ Bridge::BridgePort::getDeviceAddressRanges(AddrRangeList &resp, BEGIN_DECLARE_SIM_OBJECT_PARAMS(Bridge) - Param queue_size_a; - Param queue_size_b; + Param req_size_a; + Param req_size_b; + Param resp_size_a; + Param resp_size_b; Param delay; + Param nack_delay; Param write_ack; Param fix_partial_write_a; Param fix_partial_write_b; @@ -320,9 +357,12 @@ END_DECLARE_SIM_OBJECT_PARAMS(Bridge) BEGIN_INIT_SIM_OBJECT_PARAMS(Bridge) - INIT_PARAM(queue_size_a, "The size of the queue for data coming into side a"), - INIT_PARAM(queue_size_b, "The size of the queue for data coming into side b"), + INIT_PARAM(req_size_a, "The size of the queue for requests coming into side a"), + INIT_PARAM(req_size_b, "The size of the queue for requests coming into side b"), + INIT_PARAM(resp_size_a, "The size of the queue for responses coming into side a"), + INIT_PARAM(resp_size_b, "The size of the queue for responses coming into side b"), INIT_PARAM(delay, "The miminum delay to cross this bridge"), + INIT_PARAM(nack_delay, "The minimum delay to nack a packet"), INIT_PARAM(write_ack, "Acknowledge any writes that are received."), INIT_PARAM(fix_partial_write_a, "Fixup any partial block writes that are received"), INIT_PARAM(fix_partial_write_b, "Fixup any partial block writes that are received") @@ -331,8 +371,18 @@ END_INIT_SIM_OBJECT_PARAMS(Bridge) CREATE_SIM_OBJECT(Bridge) { - return new Bridge(getInstanceName(), queue_size_a, queue_size_b, delay, - write_ack, fix_partial_write_a, fix_partial_write_b); + Bridge::Params *p = new Bridge::Params; + p->name = getInstanceName(); + p->req_size_a = req_size_a; + p->req_size_b = req_size_b; + p->resp_size_a = resp_size_a; + p->resp_size_b = resp_size_b; + p->delay = delay; + p->nack_delay = nack_delay; + p->write_ack = write_ack; + p->fix_partial_write_a = fix_partial_write_a; + p->fix_partial_write_b = fix_partial_write_b; + return new Bridge(p); } REGISTER_SIM_OBJECT("Bridge", Bridge) -- cgit v1.2.3