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authorSteve Reinhardt <stever@eecs.umich.edu>2007-05-29 22:23:41 -0700
committerSteve Reinhardt <stever@eecs.umich.edu>2007-05-29 22:23:41 -0700
commit365e4ac37446c0ff58b035767f8047c8a8c4fd61 (patch)
tree066f7f6844290f5e767a7fd63bc4b45e34a9be08
parentcd423aa9ddf872f597e9a9fd39648025b91e72d9 (diff)
downloadgem5-365e4ac37446c0ff58b035767f8047c8a8c4fd61.tar.xz
A little more cleanup & refactoring of SimpleTimingPort.
Make it a better base class for cache ports. --HG-- extra : convert_revision : 37d6de11545a68c1a7d11ce33fe5971c51434ee4
-rw-r--r--src/mem/tport.cc88
-rw-r--r--src/mem/tport.hh21
2 files changed, 63 insertions, 46 deletions
diff --git a/src/mem/tport.cc b/src/mem/tport.cc
index 8797cf6e6..7b1c14467 100644
--- a/src/mem/tport.cc
+++ b/src/mem/tport.cc
@@ -36,7 +36,7 @@ SimpleTimingPort::checkFunctional(PacketPtr pkt)
DeferredPacketIterator i = transmitList.begin();
DeferredPacketIterator end = transmitList.end();
- while (i != end) {
+ for (; i != end; ++i) {
PacketPtr target = i->pkt;
// If the target contains data, and it overlaps the
// probed request, need to update data
@@ -46,8 +46,6 @@ SimpleTimingPort::checkFunctional(PacketPtr pkt)
return;
}
}
-
- i++;
}
}
@@ -74,7 +72,7 @@ SimpleTimingPort::recvTiming(PacketPtr pkt)
// turn packet around to go back to requester if response expected
if (pkt->needsResponse()) {
pkt->makeTimingResponse();
- sendTiming(pkt, latency);
+ schedSendTiming(pkt, latency);
}
else if (pkt->cmd != MemCmd::UpgradeReq) {
delete pkt->req;
@@ -83,81 +81,85 @@ SimpleTimingPort::recvTiming(PacketPtr pkt)
return true;
}
-void
-SimpleTimingPort::recvRetry()
-{
- assert(!transmitList.empty());
- if (Port::sendTiming(transmitList.front().pkt)) {
- transmitList.pop_front();
- DPRINTF(Bus, "No Longer waiting on retry\n");
- if (!transmitList.empty()) {
- Tick time = transmitList.front().tick;
- sendEvent->schedule(time <= curTick ? curTick+1 : time);
- }
- }
-
- if (transmitList.empty() && drainEvent) {
- drainEvent->process();
- drainEvent = NULL;
- }
-}
void
-SimpleTimingPort::sendTiming(PacketPtr pkt, Tick time)
+SimpleTimingPort::schedSendTiming(PacketPtr pkt, Tick when)
{
+ assert(when > curTick);
+
// Nothing is on the list: add it and schedule an event
if (transmitList.empty()) {
assert(!sendEvent->scheduled());
- sendEvent->schedule(curTick+time);
- transmitList.push_back(DeferredPacket(time+curTick, pkt));
+ sendEvent->schedule(when);
+ transmitList.push_back(DeferredPacket(when, pkt));
return;
}
// something is on the list and this belongs at the end
- if (time+curTick >= transmitList.back().tick) {
- transmitList.push_back(DeferredPacket(time+curTick, pkt));
+ if (when >= transmitList.back().tick) {
+ transmitList.push_back(DeferredPacket(when, pkt));
return;
}
// Something is on the list and this belongs somewhere else
DeferredPacketIterator i = transmitList.begin();
DeferredPacketIterator end = transmitList.end();
- bool done = false;
- while (i != end && !done) {
- if (time+curTick < i->tick) {
+ for (; i != end; ++i) {
+ if (when < i->tick) {
if (i == transmitList.begin()) {
//Inserting at begining, reschedule
- sendEvent->reschedule(time+curTick);
+ sendEvent->reschedule(when);
}
- transmitList.insert(i, DeferredPacket(time+curTick, pkt));
- done = true;
+ transmitList.insert(i, DeferredPacket(when, pkt));
+ return;
}
- i++;
}
- assert(done);
+ assert(false); // should never get here
}
+
void
-SimpleTimingPort::processSendEvent()
+SimpleTimingPort::sendDeferredPacket()
{
- assert(transmitList.size());
- assert(transmitList.front().tick <= curTick);
- if (Port::sendTiming(transmitList.front().pkt)) {
+ assert(deferredPacketReady());
+ bool success = sendTiming(transmitList.front().pkt);
+
+ if (success) {
//send successful, remove packet
transmitList.pop_front();
if (!transmitList.empty()) {
Tick time = transmitList.front().tick;
sendEvent->schedule(time <= curTick ? curTick+1 : time);
}
+
if (transmitList.empty() && drainEvent) {
drainEvent->process();
drainEvent = NULL;
}
- return;
}
- // send unsuccessful (due to flow control). Will get retry
- // callback later; save for then if not already
- DPRINTF(Bus, "Waiting on retry\n");
+
+ waitingOnRetry = !success;
+
+ if (waitingOnRetry) {
+ DPRINTF(Bus, "Send failed, waiting on retry\n");
+ }
+}
+
+
+void
+SimpleTimingPort::recvRetry()
+{
+ DPRINTF(Bus, "Received retry\n");
+ assert(waitingOnRetry);
+ sendDeferredPacket();
+}
+
+
+void
+SimpleTimingPort::processSendEvent()
+{
+ assert(!waitingOnRetry);
+ sendDeferredPacket();
}
diff --git a/src/mem/tport.hh b/src/mem/tport.hh
index 9e8a01786..ea0f05ed1 100644
--- a/src/mem/tport.hh
+++ b/src/mem/tport.hh
@@ -94,15 +94,29 @@ class SimpleTimingPort : public Port
* here.*/
Event *drainEvent;
+ /** Remember whether we're awaiting a retry from the bus. */
+ bool waitingOnRetry;
+
/** Check the list of buffered packets against the supplied
* functional request. */
void checkFunctional(PacketPtr funcPkt);
+ /** Check whether we have a packet ready to go on the transmit list. */
+ bool deferredPacketReady()
+ { return !transmitList.empty() && transmitList.front().tick <= curTick; }
+
/** Schedule a sendTiming() event to be called in the future.
* @param pkt packet to send
- * @param time increment from now (in ticks) to send packet
+ * @param absolute time (in ticks) to send packet
+ */
+ void schedSendTiming(PacketPtr pkt, Tick when);
+
+ /** Attempt to send the packet at the head of the deferred packet
+ * list. Caller must guarantee that the deferred packet list is
+ * non-empty and that the head packet is scheduled for curTick (or
+ * earlier).
*/
- void sendTiming(PacketPtr pkt, Tick time);
+ void sendDeferredPacket();
/** This function is notification that the device should attempt to send a
* packet again. */
@@ -126,7 +140,8 @@ class SimpleTimingPort : public Port
SimpleTimingPort(std::string pname, MemObject *_owner = NULL)
: Port(pname, _owner),
sendEvent(new SendEvent(this)),
- drainEvent(NULL)
+ drainEvent(NULL),
+ waitingOnRetry(false)
{}
~SimpleTimingPort() { delete sendEvent; }