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authorGabe Black <gblack@eecs.umich.edu>2006-10-10 15:04:55 -0400
committerGabe Black <gblack@eecs.umich.edu>2006-10-10 15:04:55 -0400
commit3a9eb598c3e71b543ba9b8fda42b76c89a645634 (patch)
treea7029e95e7ce0d406c1efee0fcaf4062410fe1f3
parent72bf1c011eb6e708cd6db9607242b7af3034b521 (diff)
parent5582e60966822fd33cf1c48abef95e4dab14235c (diff)
downloadgem5-3a9eb598c3e71b543ba9b8fda42b76c89a645634.tar.xz
Merge zizzer.eecs.umich.edu:/bk/newmem
into zeep.eecs.umich.edu:/home/gblack/m5/newmem_bus --HG-- extra : convert_revision : 6027c395af044858465eafd3ea78bcfe4c923bcc
-rw-r--r--src/mem/bus.cc68
-rw-r--r--src/mem/bus.hh2
-rw-r--r--src/mem/packet.hh7
-rw-r--r--src/mem/tport.cc9
4 files changed, 52 insertions, 34 deletions
diff --git a/src/mem/bus.cc b/src/mem/bus.cc
index 7584ffffd..66cd581e7 100644
--- a/src/mem/bus.cc
+++ b/src/mem/bus.cc
@@ -82,33 +82,6 @@ const char * Bus::BusFreeEvent::description()
return "bus became available";
}
-void
-Bus::occupyBus(int numCycles)
-{
- //Move up when the bus will next be free
- //We avoid the use of divide by adding repeatedly
- //This should be faster if the value is updated frequently, but should
- //be may be slower otherwise.
-
- //Bring tickNextIdle up to the present tick
- //There is some potential ambiguity where a cycle starts, which might make
- //a difference when devices are acting right around a cycle boundary. Using
- //a < allows things which happen exactly on a cycle boundary to take up only
- //the following cycle. Anthing that happens later will have to "wait" for the
- //end of that cycle, and then start using the bus after that.
- while (tickNextIdle < curTick)
- tickNextIdle += clock;
- //Advance it numCycles bus cycles.
- //XXX Should this use the repeating add trick as well?
- tickNextIdle += (numCycles * clock);
- if (!busIdle.scheduled()) {
- busIdle.schedule(tickNextIdle);
- } else {
- busIdle.reschedule(tickNextIdle);
- }
- DPRINTF(Bus, "The bus is now occupied from tick %d to %d\n", curTick, tickNextIdle);
-}
-
/** Function called by the port when the bus is receiving a Timing
* transaction.*/
bool
@@ -120,6 +93,14 @@ Bus::recvTiming(Packet *pkt)
Port *pktPort = interfaces[pkt->getSrc()];
+ // If the bus is busy, or other devices are in line ahead of the current
+ // one, put this device on the retry list.
+ if (tickNextIdle > curTick ||
+ (retryList.size() && pktPort != retryingPort)) {
+ addToRetryList(pktPort);
+ return false;
+ }
+
short dest = pkt->getDest();
if (dest == Packet::Broadcast) {
if (timingSnoop(pkt)) {
@@ -146,7 +127,17 @@ Bus::recvTiming(Packet *pkt)
port = interfaces[dest];
}
- // The packet will be sent. Figure out how long it occupies the bus.
+ //Bring tickNextIdle up to the present tick
+ //There is some potential ambiguity where a cycle starts, which might make
+ //a difference when devices are acting right around a cycle boundary. Using
+ //a < allows things which happen exactly on a cycle boundary to take up only
+ //the following cycle. Anthing that happens later will have to "wait" for
+ //the end of that cycle, and then start using the bus after that.
+ while (tickNextIdle < curTick)
+ tickNextIdle += clock;
+
+ // The packet will be sent. Figure out how long it occupies the bus, and
+ // how much of that time is for the first "word", aka bus width.
int numCycles = 0;
// Requests need one cycle to send an address
if (pkt->isRequest())
@@ -167,7 +158,26 @@ Bus::recvTiming(Packet *pkt)
}
}
- occupyBus(numCycles);
+ // The first word will be delivered after the current tick, the delivery
+ // of the address if any, and one bus cycle to deliver the data
+ pkt->firstWordTime =
+ tickNextIdle +
+ pkt->isRequest() ? clock : 0 +
+ clock;
+
+ //Advance it numCycles bus cycles.
+ //XXX Should this use the repeated addition trick as well?
+ tickNextIdle += (numCycles * clock);
+ if (!busIdle.scheduled()) {
+ busIdle.schedule(tickNextIdle);
+ } else {
+ busIdle.reschedule(tickNextIdle);
+ }
+ DPRINTF(Bus, "The bus is now occupied from tick %d to %d\n",
+ curTick, tickNextIdle);
+
+ // The bus will become idle once the current packet is delivered.
+ pkt->finishTime = tickNextIdle;
if (port->sendTiming(pkt)) {
// Packet was successfully sent. Return true.
diff --git a/src/mem/bus.hh b/src/mem/bus.hh
index a89738775..ce3f4bed7 100644
--- a/src/mem/bus.hh
+++ b/src/mem/bus.hh
@@ -195,8 +195,6 @@ class Bus : public MemObject
BusFreeEvent busIdle;
- void occupyBus(int numCycles);
-
Port * retryingPort;
/** An array of pointers to the peer port interfaces
diff --git a/src/mem/packet.hh b/src/mem/packet.hh
index 7ec061710..3a7286a69 100644
--- a/src/mem/packet.hh
+++ b/src/mem/packet.hh
@@ -92,7 +92,6 @@ class Packet
* be called on it rather than simply delete.*/
bool arrayData;
-
/** The address of the request. This address could be virtual or
* physical, depending on the system configuration. */
Addr addr;
@@ -124,6 +123,12 @@ class Packet
/** Used to calculate latencies for each packet.*/
Tick time;
+ /** The time at which the packet will be fully transmitted */
+ Tick finishTime;
+
+ /** The time at which the first chunk of the packet will be transmitted */
+ Tick firstWordTime;
+
/** The special destination address indicating that the packet
* should be routed based on its address. */
static const short Broadcast = -1;
diff --git a/src/mem/tport.cc b/src/mem/tport.cc
index cef7a2a5b..66811b820 100644
--- a/src/mem/tport.cc
+++ b/src/mem/tport.cc
@@ -59,6 +59,8 @@ void
SimpleTimingPort::recvRetry()
{
bool result = true;
+
+ assert(transmitList.size());
while (result && transmitList.size()) {
result = sendTiming(transmitList.front());
if (result)
@@ -75,8 +77,11 @@ SimpleTimingPort::SendEvent::process()
{
port->outTiming--;
assert(port->outTiming >= 0);
- if (port->sendTiming(packet)) {
- // send successfule
+ if (port->transmitList.size()) {
+ port->transmitList.push_back(packet);
+ }
+ else if (port->sendTiming(packet)) {
+ // send successful
if (port->transmitList.size() == 0 && port->drainEvent) {
port->drainEvent->process();
port->drainEvent = NULL;