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authorAli Saidi <saidi@eecs.umich.edu>2006-05-30 18:57:42 -0400
committerAli Saidi <saidi@eecs.umich.edu>2006-05-30 18:57:42 -0400
commit09d8a1e1252eba582fd8450ee31e784b54910f7d (patch)
tree90790e6ea9e1575eb2a81715a33eddccb091bd82 /src
parente60dc5195ce36bc055e9ea6899df9968bccafe9f (diff)
downloadgem5-09d8a1e1252eba582fd8450ee31e784b54910f7d.tar.xz
Add a very poor implementation of dealing with retries on timing requests. It is especially slow with tracing on since
it ends up being O(N^2). But it's probably going to have to change for the real bus anyway, so it should be rewritten then Change recvRetry() to not accept a packet. Sendtiming should be called again (and can respond with false or true) Removed Port Blocked/Unblocked and replaced with sendRetry(). Remove possibility of packet mangling if packet is going to be refused anyway in bridge src/cpu/simple/atomic.cc: src/cpu/simple/atomic.hh: src/cpu/simple/timing.cc: src/cpu/simple/timing.hh: Change recvRetry() to not accept a packet. Sendtiming should be called again (and can respond with false or true) src/dev/io_device.cc: src/dev/io_device.hh: Make DMA Timing requests/responses work. Change recvRetry() to not accept a packet. Sendtiming should be called again (and can respond with false or true) src/mem/bridge.cc: src/mem/bridge.hh: Change recvRetry() to not accept a packet. Sendtiming should be called again (and can respond with false or true) Removed Port Blocked/Unblocked and replaced with sendRetry(). Remove posibility of packet mangling if packet is going to be refused anyway. src/mem/bus.cc: src/mem/bus.hh: Add a very poor implementation of dealing with retries on timing requests. It is especially slow with tracing on since it ends up being O(N^2). But it's probably going to have to change for the real bus anyway, so it should be rewritten then src/mem/port.hh: Change recvRetry() to not accept a packet. Sendtiming should be called again (and can respond with false or true) Removed Blocked/Unblocked port status, their functionality is really duplicated in the recvRetry() method --HG-- extra : convert_revision : fab613404be54bfa7a4c67572bae7b559169e573
Diffstat (limited to 'src')
-rw-r--r--src/cpu/simple/atomic.cc3
-rw-r--r--src/cpu/simple/atomic.hh2
-rw-r--r--src/cpu/simple/timing.cc18
-rw-r--r--src/cpu/simple/timing.hh4
-rw-r--r--src/dev/io_device.cc57
-rw-r--r--src/dev/io_device.hh26
-rw-r--r--src/mem/bridge.cc93
-rw-r--r--src/mem/bridge.hh6
-rw-r--r--src/mem/bus.cc28
-rw-r--r--src/mem/bus.hh13
-rw-r--r--src/mem/port.hh12
11 files changed, 146 insertions, 116 deletions
diff --git a/src/cpu/simple/atomic.cc b/src/cpu/simple/atomic.cc
index 3cad6e43f..a0d26a8ab 100644
--- a/src/cpu/simple/atomic.cc
+++ b/src/cpu/simple/atomic.cc
@@ -106,11 +106,10 @@ AtomicSimpleCPU::CpuPort::recvStatusChange(Status status)
panic("AtomicSimpleCPU doesn't expect recvStatusChange callback!");
}
-Packet *
+void
AtomicSimpleCPU::CpuPort::recvRetry()
{
panic("AtomicSimpleCPU doesn't expect recvRetry callback!");
- return NULL;
}
diff --git a/src/cpu/simple/atomic.hh b/src/cpu/simple/atomic.hh
index ab3a3e8ef..65269bd6d 100644
--- a/src/cpu/simple/atomic.hh
+++ b/src/cpu/simple/atomic.hh
@@ -98,7 +98,7 @@ class AtomicSimpleCPU : public BaseSimpleCPU
virtual void recvStatusChange(Status status);
- virtual Packet *recvRetry();
+ virtual void recvRetry();
virtual void getDeviceAddressRanges(AddrRangeList &resp,
AddrRangeList &snoop)
diff --git a/src/cpu/simple/timing.cc b/src/cpu/simple/timing.cc
index 7cdcdafa1..5f094d033 100644
--- a/src/cpu/simple/timing.cc
+++ b/src/cpu/simple/timing.cc
@@ -419,17 +419,18 @@ TimingSimpleCPU::IcachePort::recvTiming(Packet *pkt)
return true;
}
-Packet *
+void
TimingSimpleCPU::IcachePort::recvRetry()
{
// we shouldn't get a retry unless we have a packet that we're
// waiting to transmit
assert(cpu->ifetch_pkt != NULL);
assert(cpu->_status == IcacheRetry);
- cpu->_status = IcacheWaitResponse;
Packet *tmp = cpu->ifetch_pkt;
- cpu->ifetch_pkt = NULL;
- return tmp;
+ if (sendTiming(tmp)) {
+ cpu->_status = IcacheWaitResponse;
+ cpu->ifetch_pkt = NULL;
+ }
}
void
@@ -459,17 +460,18 @@ TimingSimpleCPU::DcachePort::recvTiming(Packet *pkt)
return true;
}
-Packet *
+void
TimingSimpleCPU::DcachePort::recvRetry()
{
// we shouldn't get a retry unless we have a packet that we're
// waiting to transmit
assert(cpu->dcache_pkt != NULL);
assert(cpu->_status == DcacheRetry);
- cpu->_status = DcacheWaitResponse;
Packet *tmp = cpu->dcache_pkt;
- cpu->dcache_pkt = NULL;
- return tmp;
+ if (sendTiming(tmp)) {
+ cpu->_status = DcacheWaitResponse;
+ cpu->dcache_pkt = NULL;
+ }
}
diff --git a/src/cpu/simple/timing.hh b/src/cpu/simple/timing.hh
index b46631d5a..cb37824bc 100644
--- a/src/cpu/simple/timing.hh
+++ b/src/cpu/simple/timing.hh
@@ -100,7 +100,7 @@ class TimingSimpleCPU : public BaseSimpleCPU
virtual bool recvTiming(Packet *pkt);
- virtual Packet *recvRetry();
+ virtual void recvRetry();
};
class DcachePort : public CpuPort
@@ -115,7 +115,7 @@ class TimingSimpleCPU : public BaseSimpleCPU
virtual bool recvTiming(Packet *pkt);
- virtual Packet *recvRetry();
+ virtual void recvRetry();
};
IcachePort icachePort;
diff --git a/src/dev/io_device.cc b/src/dev/io_device.cc
index 87fdbb765..563fdb759 100644
--- a/src/dev/io_device.cc
+++ b/src/dev/io_device.cc
@@ -26,6 +26,7 @@
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
+#include "base/trace.hh"
#include "dev/io_device.hh"
#include "sim/builder.hh"
@@ -55,12 +56,13 @@ PioPort::getDeviceAddressRanges(AddrRangeList &resp, AddrRangeList &snoop)
}
-Packet *
+void
PioPort::recvRetry()
{
Packet* pkt = transmitList.front();
- transmitList.pop_front();
- return pkt;
+ if (Port::sendTiming(pkt)) {
+ transmitList.pop_front();
+ }
}
@@ -74,6 +76,7 @@ PioPort::SendEvent::process()
}
+
bool
PioPort::recvTiming(Packet *pkt)
{
@@ -116,16 +119,20 @@ DmaPort::recvTiming(Packet *pkt)
{
if (pkt->senderState) {
DmaReqState *state;
+ DPRINTF(DMA, "Received response Packet %#x with senderState: %#x\n",
+ pkt, pkt->senderState);
state = dynamic_cast<DmaReqState*>(pkt->senderState);
- state->completionEvent->schedule(pkt->time - pkt->req->getTime());
+ assert(state);
+ state->completionEvent->process();
delete pkt->req;
delete pkt;
} else {
+ DPRINTF(DMA, "Received response Packet %#x with no senderState\n", pkt);
delete pkt->req;
delete pkt;
}
- return Packet::Success;
+ return true;
}
DmaDevice::DmaDevice(Params *p)
@@ -133,20 +140,19 @@ DmaDevice::DmaDevice(Params *p)
{ }
void
-DmaPort::SendEvent::process()
-{
- if (port->Port::sendTiming(packet))
- return;
-
- port->transmitList.push_back(packet);
-}
-
-Packet *
DmaPort::recvRetry()
{
Packet* pkt = transmitList.front();
- transmitList.pop_front();
- return pkt;
+ DPRINTF(DMA, "Retry on Packet %#x with senderState: %#x\n",
+ pkt, pkt->senderState);
+ if (sendTiming(pkt)) {
+ DPRINTF(DMA, "-- Done\n");
+ transmitList.pop_front();
+ pendingCount--;
+ assert(pendingCount >= 0);
+ } else {
+ DPRINTF(DMA, "-- Failed, queued\n");
+ }
}
@@ -192,13 +198,22 @@ DmaPort::sendDma(Packet *pkt)
// switching actually work
/* MemState state = device->platform->system->memState;
- if (state == Timing) {
- if (!sendTiming(pkt))
- transmitList.push_back(&packet);
- } else if (state == Atomic) {*/
+ if (state == Timing) { */
+ DPRINTF(DMA, "Attempting to send Packet %#x with senderState: %#x\n",
+ pkt, pkt->senderState);
+ if (!sendTiming(pkt)) {
+ transmitList.push_back(pkt);
+ DPRINTF(DMA, "-- Failed: queued\n");
+ } else {
+ DPRINTF(DMA, "-- Done\n");
+ pendingCount--;
+ assert(pendingCount >= 0);
+ }
+ /* } else if (state == Atomic) {
sendAtomic(pkt);
if (pkt->senderState) {
DmaReqState *state = dynamic_cast<DmaReqState*>(pkt->senderState);
+ assert(state);
state->completionEvent->schedule(curTick + (pkt->time - pkt->req->getTime()) +1);
}
pendingCount--;
@@ -206,7 +221,7 @@ DmaPort::sendDma(Packet *pkt)
delete pkt->req;
delete pkt;
-/* } else if (state == Functional) {
+ } else if (state == Functional) {
sendFunctional(pkt);
// Is this correct???
completionEvent->schedule(pkt->req->responseTime - pkt->req->requestTime);
diff --git a/src/dev/io_device.hh b/src/dev/io_device.hh
index 74730ad92..5836da3c9 100644
--- a/src/dev/io_device.hh
+++ b/src/dev/io_device.hh
@@ -105,8 +105,9 @@ class PioPort : public Port
void sendTiming(Packet *pkt, Tick time)
{ new PioPort::SendEvent(this, pkt, time); }
- /** This function pops the last element off the transmit list and sends it.*/
- virtual Packet *recvRetry();
+ /** This function is notification that the device should attempt to send a
+ * packet again. */
+ virtual void recvRetry();
public:
PioPort(PioDevice *dev, Platform *p);
@@ -146,28 +147,11 @@ class DmaPort : public Port
virtual void recvStatusChange(Status status)
{ ; }
- virtual Packet *recvRetry() ;
+ virtual void recvRetry() ;
virtual void getDeviceAddressRanges(AddrRangeList &resp, AddrRangeList &snoop)
{ resp.clear(); snoop.clear(); }
- class SendEvent : public Event
- {
- DmaPort *port;
- Packet *packet;
-
- SendEvent(PioPort *p, Packet *pkt, Tick t)
- : Event(&mainEventQueue), packet(pkt)
- { schedule(curTick + t); }
-
- virtual void process();
-
- virtual const char *description()
- { return "Future scheduled sendTiming event"; }
-
- friend class DmaPort;
- };
-
void sendDma(Packet *pkt);
public:
@@ -178,8 +162,6 @@ class DmaPort : public Port
bool dmaPending() { return pendingCount > 0; }
- friend class DmaPort::SendEvent;
-
};
/**
diff --git a/src/mem/bridge.cc b/src/mem/bridge.cc
index 736e8dc81..5b8b9164b 100644
--- a/src/mem/bridge.cc
+++ b/src/mem/bridge.cc
@@ -90,7 +90,17 @@ Bridge::BridgePort::recvTiming(Packet *pkt)
DPRINTF(BusBridge, "recvTiming: src %d dest %d addr 0x%x\n",
pkt->getSrc(), pkt->getDest(), pkt->getAddr());
- if (pkt->isResponse()) {
+ return otherPort->queueForSendTiming(pkt);
+}
+
+
+bool
+Bridge::BridgePort::queueForSendTiming(Packet *pkt)
+{
+ if (queueFull())
+ return false;
+
+ if (pkt->isResponse()) {
// This is a response for a request we forwarded earlier. The
// corresponding PacketBuffer should be stored in the packet's
// senderState field.
@@ -99,22 +109,16 @@ Bridge::BridgePort::recvTiming(Packet *pkt)
// set up new packet dest & senderState based on values saved
// from original request
buf->fixResponse(pkt);
+ DPRINTF(BusBridge, "restoring sender state: %#X, from packet buffer: %#X\n",
+ pkt->senderState, buf);
DPRINTF(BusBridge, " is response, new dest %d\n", pkt->getDest());
delete buf;
}
- return otherPort->queueForSendTiming(pkt);
-}
-
-
-bool
-Bridge::BridgePort::queueForSendTiming(Packet *pkt)
-{
- if (queueFull())
- return false;
-
Tick readyTime = curTick + delay;
PacketBuffer *buf = new PacketBuffer(pkt, readyTime);
+ DPRINTF(BusBridge, "old sender state: %#X, new sender state: %#X\n",
+ buf->origSenderState, buf);
// If we're about to put this packet at the head of the queue, we
// need to schedule an event to do the transmit. Otherwise there
@@ -126,43 +130,16 @@ Bridge::BridgePort::queueForSendTiming(Packet *pkt)
sendQueue.push_back(buf);
- // Did we just become blocked? If yes, let other side know.
- if (queueFull())
- otherPort->sendStatusChange(Port::Blocked);
-
return true;
}
-
-void
-Bridge::BridgePort::finishSend(PacketBuffer *buf)
-{
- 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;
- DPRINTF(BusBridge, " successful: awaiting response (%d)\n",
- outstandingResponses);
- } else {
- // no response expected... deallocate packet buffer now.
- DPRINTF(BusBridge, " successful: no response expected\n");
- delete buf;
- }
-
- // If there are more packets to send, schedule event to try again.
- if (!sendQueue.empty()) {
- buf = sendQueue.front();
- sendEvent.schedule(std::max(buf->ready, curTick + 1));
- }
-}
-
-
void
Bridge::BridgePort::trySend()
{
assert(!sendQueue.empty());
+ bool was_full = queueFull();
+
PacketBuffer *buf = sendQueue.front();
assert(buf->ready <= curTick);
@@ -176,20 +153,41 @@ Bridge::BridgePort::trySend()
// send successful
sendQueue.pop_front();
buf->pkt = NULL; // we no longer own packet, so it's not safe to look at it
- finishSend(buf);
+
+ 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;
+ DPRINTF(BusBridge, " successful: awaiting response (%d)\n",
+ outstandingResponses);
+ } else {
+ // no response expected... deallocate packet buffer now.
+ DPRINTF(BusBridge, " successful: no response expected\n");
+ delete buf;
+ }
+
+ // If there are more packets to send, schedule event to try again.
+ if (!sendQueue.empty()) {
+ buf = sendQueue.front();
+ 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");
}
}
-Packet *
+void
Bridge::BridgePort::recvRetry()
{
- PacketBuffer *buf = sendQueue.front();
- Packet *pkt = buf->pkt;
- finishSend(buf);
- return pkt;
+ trySend();
}
/** Function called by the port when the bus is receiving a Atomic
@@ -223,9 +221,6 @@ Bridge::BridgePort::recvFunctional(Packet *pkt)
void
Bridge::BridgePort::recvStatusChange(Port::Status status)
{
- if (status == Port::Blocked || status == Port::Unblocked)
- return;
-
otherPort->sendStatusChange(status);
}
diff --git a/src/mem/bridge.hh b/src/mem/bridge.hh
index 8a5cbf92a..8c7af562c 100644
--- a/src/mem/bridge.hh
+++ b/src/mem/bridge.hh
@@ -38,7 +38,6 @@
#include <inttypes.h>
#include <queue>
-
#include "mem/mem_object.hh"
#include "mem/packet.hh"
#include "mem/port.hh"
@@ -77,7 +76,8 @@ class Bridge : public MemObject
origSenderState(_pkt->senderState), origSrc(_pkt->getSrc()),
expectResponse(_pkt->needsResponse())
{
- pkt->senderState = this;
+ if (!pkt->isResponse())
+ pkt->senderState = this;
}
void fixResponse(Packet *pkt)
@@ -146,7 +146,7 @@ class Bridge : public MemObject
/** When receiving a retry request from the peer port,
pass it to the bridge. */
- virtual Packet* recvRetry();
+ virtual void recvRetry();
/** When receiving a Atomic requestfrom the peer port,
pass it to the bridge. */
diff --git a/src/mem/bus.cc b/src/mem/bus.cc
index cfc99a64f..aec3ef2f6 100644
--- a/src/mem/bus.cc
+++ b/src/mem/bus.cc
@@ -72,9 +72,35 @@ Bus::recvTiming(Packet *pkt)
assert(dest != pkt->getSrc()); // catch infinite loops
port = interfaces[dest];
}
- return port->sendTiming(pkt);
+ if (port->sendTiming(pkt)) {
+ // packet was successfully sent, just return true.
+ return true;
+ }
+
+ // packet not successfully sent
+ retryList.push_back(interfaces[pkt->getSrc()]);
+ return false;
+}
+
+void
+Bus::recvRetry(int id)
+{
+ // Go through all the elements on the list calling sendRetry on each
+ // This is not very efficient at all but it works. Ultimately we should end
+ // up with something that is more intelligent.
+ int initialSize = retryList.size();
+ int i;
+ Port *p;
+
+ for (i = 0; i < initialSize; i++) {
+ assert(retryList.size() > 0);
+ p = retryList.front();
+ retryList.pop_front();
+ p->sendRetry();
+ }
}
+
Port *
Bus::findPort(Addr addr, int id)
{
diff --git a/src/mem/bus.hh b/src/mem/bus.hh
index 5eeb07904..774f9f3a4 100644
--- a/src/mem/bus.hh
+++ b/src/mem/bus.hh
@@ -67,6 +67,10 @@ class Bus : public MemObject
transaction.*/
void recvFunctional(Packet *pkt);
+ /** Timing function called by port when it is once again able to process
+ * requests. */
+ void recvRetry(int id);
+
/** Function called by the port when the bus is recieving a status change.*/
void recvStatusChange(Port::Status status, int id);
@@ -126,6 +130,11 @@ class Bus : public MemObject
virtual void recvStatusChange(Status status)
{ bus->recvStatusChange(status, id); }
+ /** When reciving a retry from the peer port (at id),
+ pass it to the bus. */
+ virtual void recvRetry()
+ { bus->recvRetry(id); }
+
// This should return all the 'owned' addresses that are
// downstream from this bus, yes? That is, the union of all
// the 'owned' address ranges of all the other interfaces on
@@ -143,6 +152,10 @@ class Bus : public MemObject
connected to this bus.*/
std::vector<Port*> interfaces;
+ /** An array of pointers to ports that retry should be called on because the
+ * original send failed for whatever reason.*/
+ std::list<Port*> retryList;
+
public:
/** A function used to return the port associated with this bus object. */
diff --git a/src/mem/port.hh b/src/mem/port.hh
index f9103865e..79fbf1fdb 100644
--- a/src/mem/port.hh
+++ b/src/mem/port.hh
@@ -92,11 +92,9 @@ class Port
virtual ~Port() {};
// mey be better to use subclasses & RTTI?
- /** Holds the ports status. Keeps track if it is blocked, or has
- calculated a range change. */
+ /** Holds the ports status. Currently just that a range recomputation needs
+ * to be done. */
enum Status {
- Blocked,
- Unblocked,
RangeChange
};
@@ -140,7 +138,7 @@ class Port
wait. This shouldn't be valid for response paths (IO Devices).
so it is set to panic if it isn't already defined.
*/
- virtual Packet *recvRetry() { panic("??"); }
+ virtual void recvRetry() { panic("??"); }
/** Called by a peer port in order to determine the block size of the
device connected to this port. It sometimes doesn't make sense for
@@ -165,7 +163,7 @@ class Port
port receive function.
@return This function returns if the send was succesful in it's
recieve. If it was a failure, then the port will wait for a recvRetry
- at which point it can issue a successful sendTiming. This is used in
+ at which point it can possibly issue a successful sendTiming. This is used in
case a cache has a higher priority request come in while waiting for
the bus to arbitrate.
*/
@@ -194,7 +192,7 @@ class Port
/** When a timing access doesn't return a success, some time later the
Retry will be sent.
*/
- Packet *sendRetry() { return peer->recvRetry(); }
+ void sendRetry() { return peer->recvRetry(); }
/** Called by the associated device if it wishes to find out the blocksize
of the device on attached to the peer port.