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-rw-r--r--src/mem/bridge.cc189
1 files changed, 143 insertions, 46 deletions
diff --git a/src/mem/bridge.cc b/src/mem/bridge.cc
index b25d135e2..e89473be3 100644
--- a/src/mem/bridge.cc
+++ b/src/mem/bridge.cc
@@ -43,21 +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), 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");
@@ -92,34 +93,105 @@ Bridge::init()
fatal("Busses don't have the same block size... Not supported.\n");
}
+bool
+Bridge::BridgePort::respQueueFull()
+{
+ 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
* transaction.*/
bool
Bridge::BridgePort::recvTiming(PacketPtr pkt)
{
- if (pkt->flags & SNOOP_COMMIT) {
- DPRINTF(BusBridge, "recvTiming: src %d dest %d addr 0x%x\n",
+ if (!(pkt->flags & SNOOP_COMMIT))
+ return true;
+
+
+ DPRINTF(BusBridge, "recvTiming: src %d dest %d addr 0x%x\n",
pkt->getSrc(), pkt->getDest(), pkt->getAddr());
- return otherPort->queueForSendTiming(pkt);
+ if (pkt->isRequest() && otherPort->reqQueueFull()) {
+ DPRINTF(BusBridge, "Remote queue full, nacking\n");
+ nackRequest(pkt);
+ return true;
+ }
+
+ if (pkt->needsResponse() && pkt->result != Packet::Nacked)
+ 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);
+ nackRequest(pkt);
+ return true;
+ } else {
+ DPRINTF(BusBridge, "Request Needs response, reserving space\n");
+ ++outstandingResponses;
+ }
+
+ otherPort->queueForSendTiming(pkt);
+
+ return true;
+}
+
+void
+Bridge::BridgePort::nackRequest(PacketPtr pkt)
+{
+ // Nack the packet
+ pkt->result = Packet::Nacked;
+ pkt->setDest(pkt->getSrc());
+
+ //put it on the list to send
+ 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;
+ }
+
+ assert(sendEvent.scheduled() || inRetry);
+
+ // does it go at the end?
+ if (readyTime >= sendQueue.back()->ready) {
+ sendQueue.push_back(buf);
+ return;
}
- else {
- // Else it's just a snoop, properly return if we are blocking
- return !queueFull();
+
+ // ok, somewhere in the middle, fun
+ std::list<PacketBuffer*>::iterator i = sendQueue.begin();
+ std::list<PacketBuffer*>::iterator end = sendQueue.end();
+ std::list<PacketBuffer*>::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);
}
-bool
+void
Bridge::BridgePort::queueForSendTiming(PacketPtr pkt)
{
- if (queueFull()) {
- DPRINTF(BusBridge, "Queue full, returning false\n");
- return false;
- }
-
- if (pkt->isResponse()) {
+ if (pkt->isResponse() || pkt->result == Packet::Nacked) {
// This is a response for a request we forwarded earlier. The
// corresponding PacketBuffer should be stored in the packet's
// senderState field.
@@ -128,6 +200,13 @@ Bridge::BridgePort::queueForSendTiming(PacketPtr pkt)
// set up new packet dest & senderState based on values saved
// from original request
buf->fixResponse(pkt);
+
+ // Check if this packet was expecting a response (this is either it or
+ // its a nacked packet and we won't be seeing that response)
+ if (buf->expectResponse)
+ --outstandingResponses;
+
+
DPRINTF(BusBridge, "restoring sender state: %#X, from packet buffer: %#X\n",
pkt->senderState, buf);
DPRINTF(BusBridge, " is response, new dest %d\n", pkt->getDest());
@@ -146,10 +225,8 @@ Bridge::BridgePort::queueForSendTiming(PacketPtr pkt)
if (sendQueue.empty()) {
sendEvent.schedule(readyTime);
}
-
+ ++queuedRequests;
sendQueue.push_back(buf);
-
- return true;
}
void
@@ -157,7 +234,6 @@ Bridge::BridgePort::trySend()
{
assert(!sendQueue.empty());
- bool was_full = queueFull();
int pbs = peerBlockSize();
PacketBuffer *buf = sendQueue.front();
@@ -169,7 +245,8 @@ Bridge::BridgePort::trySend()
pkt->flags &= ~SNOOP_COMMIT; //CLear it if it was set
if (pkt->cmd == MemCmd::WriteInvalidateReq && fixPartialWrite &&
- pkt->getOffset(pbs) && pkt->getSize() != pbs) {
+ pkt->result != Packet::Nacked && pkt->getOffset(pbs) &&
+ pkt->getSize() != pbs) {
buf->partialWriteFix(this);
pkt = buf->pkt;
}
@@ -184,10 +261,7 @@ Bridge::BridgePort::trySend()
buf->pkt = NULL; // we no longer own packet, so it's not safe to look at it
if (buf->expectResponse) {
- // Must wait for response. We just need to count outstanding
- // responses (in case we want to cap them); PacketBuffer
- // pointer will be recovered on response.
- ++outstandingResponses;
+ // Must wait for response
DPRINTF(BusBridge, " successful: awaiting response (%d)\n",
outstandingResponses);
} else {
@@ -196,28 +270,34 @@ Bridge::BridgePort::trySend()
delete buf;
}
+ if (!buf->nacked)
+ --queuedRequests;
+
// If there are more packets to send, schedule event to try again.
if (!sendQueue.empty()) {
buf = sendQueue.front();
+ DPRINTF(BusBridge, "Scheduling next send\n");
sendEvent.schedule(std::max(buf->ready, curTick + 1));
}
- // Let things start sending again
- if (was_full) {
- 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);
}
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
@@ -263,9 +343,12 @@ Bridge::BridgePort::getDeviceAddressRanges(AddrRangeList &resp,
BEGIN_DECLARE_SIM_OBJECT_PARAMS(Bridge)
- Param<int> queue_size_a;
- Param<int> queue_size_b;
+ Param<int> req_size_a;
+ Param<int> req_size_b;
+ Param<int> resp_size_a;
+ Param<int> resp_size_b;
Param<Tick> delay;
+ Param<Tick> nack_delay;
Param<bool> write_ack;
Param<bool> fix_partial_write_a;
Param<bool> fix_partial_write_b;
@@ -274,9 +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")
@@ -285,8 +371,19 @@ 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)
+
generated by cgit v1.2.3 (git 2.25.1) at 2024-10-25 21:13:42 +0000