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

7 files changed, 122 insertions, 19 deletions

diff --git a/src/dev/i8254xGBe.cc b/src/dev/i8254xGBe.cc
index 6acd06132..e54249dee 100644
--- a/src/dev/i8254xGBe.cc
+++ b/src/dev/i8254xGBe.cc
@@ -1460,6 +1460,8 @@ BEGIN_DECLARE_SIM_OBJECT_PARAMS(IGbE)
 
     SimObjectParam<System *> system;
     SimObjectParam<Platform *> platform;
+    Param<Tick> min_backoff_delay;
+    Param<Tick> max_backoff_delay;
     SimObjectParam<PciConfigData *> configdata;
     Param<uint32_t> pci_bus;
     Param<uint32_t> pci_dev;
@@ -1481,6 +1483,8 @@ BEGIN_INIT_SIM_OBJECT_PARAMS(IGbE)
 
     INIT_PARAM(system, "System pointer"),
     INIT_PARAM(platform, "Platform pointer"),
+    INIT_PARAM(min_backoff_delay, "Minimum delay after receving a nack packed"),
+    INIT_PARAM(max_backoff_delay, "Maximum delay after receving a nack packed"),
     INIT_PARAM(configdata, "PCI Config data"),
     INIT_PARAM(pci_bus, "PCI bus ID"),
     INIT_PARAM(pci_dev, "PCI device number"),
@@ -1505,6 +1509,8 @@ CREATE_SIM_OBJECT(IGbE)
     params->name = getInstanceName();
     params->platform = platform;
     params->system = system;
+    params->min_backoff_delay = min_backoff_delay;
+    params->max_backoff_delay = max_backoff_delay;
     params->configData = configdata;
     params->busNum = pci_bus;
     params->deviceNum = pci_dev;
diff --git a/src/dev/ide_ctrl.cc b/src/dev/ide_ctrl.cc
index 1afad529f..921ba1cd0 100644
--- a/src/dev/ide_ctrl.cc
+++ b/src/dev/ide_ctrl.cc
@@ -751,6 +751,8 @@ BEGIN_DECLARE_SIM_OBJECT_PARAMS(IdeController)
 
     SimObjectParam<System *> system;
     SimObjectParam<Platform *> platform;
+    Param<Tick> min_backoff_delay;
+    Param<Tick> max_backoff_delay;
     SimObjectParam<PciConfigData *> configdata;
     Param<uint32_t> pci_bus;
     Param<uint32_t> pci_dev;
@@ -765,6 +767,8 @@ BEGIN_INIT_SIM_OBJECT_PARAMS(IdeController)
 
     INIT_PARAM(system, "System pointer"),
     INIT_PARAM(platform, "Platform pointer"),
+    INIT_PARAM(min_backoff_delay, "Minimum delay after receving a nack packed"),
+    INIT_PARAM(max_backoff_delay, "Maximum delay after receving a nack packed"),
     INIT_PARAM(configdata, "PCI Config data"),
     INIT_PARAM(pci_bus, "PCI bus ID"),
     INIT_PARAM(pci_dev, "PCI device number"),
@@ -781,6 +785,8 @@ CREATE_SIM_OBJECT(IdeController)
     params->name = getInstanceName();
     params->platform = platform;
     params->system = system;
+    params->min_backoff_delay = min_backoff_delay;
+    params->max_backoff_delay = max_backoff_delay;
     params->configData = configdata;
     params->busNum = pci_bus;
     params->deviceNum = pci_dev;
diff --git a/src/dev/io_device.cc b/src/dev/io_device.cc
index a1285fefc..9384c4b92 100644
--- a/src/dev/io_device.cc
+++ b/src/dev/io_device.cc
@@ -93,7 +93,8 @@ BasicPioDevice::addressRanges(AddrRangeList &range_list)
 
 DmaPort::DmaPort(DmaDevice *dev, System *s)
     : Port(dev->name() + "-dmaport", dev), device(dev), sys(s),
-      pendingCount(0), actionInProgress(0), drainEvent(NULL)
+      pendingCount(0), actionInProgress(0), drainEvent(NULL),
+      backoffTime(0), inRetry(false), backoffEvent(this)
 { }
 
 bool
@@ -104,12 +105,27 @@ DmaPort::recvTiming(PacketPtr pkt)
     if (pkt->result == Packet::Nacked) {
         DPRINTF(DMA, "Received nacked Pkt %#x with State: %#x Addr: %#x\n",
                pkt, pkt->senderState, pkt->getAddr());
+
+        if (backoffTime < device->minBackoffDelay)
+            backoffTime = device->minBackoffDelay;
+        else if (backoffTime < device->maxBackoffDelay)
+            backoffTime <<= 1;
+
+        if (backoffEvent.scheduled())
+            backoffEvent.reschedule(curTick + backoffTime);
+        else
+            backoffEvent.schedule(curTick + backoffTime);
+
+        DPRINTF(DMA, "Backoff time set to %d ticks\n", backoffTime);
+
         pkt->reinitNacked();
-        sendDma(pkt, true);
+        queueDma(pkt, true);
     } else if (pkt->senderState) {
         DmaReqState *state;
-        DPRINTF(DMA, "Received response Pkt %#x with State: %#x Addr: %#x\n",
-               pkt, pkt->senderState, pkt->getAddr());
+        backoffTime >>= 2;
+
+        DPRINTF(DMA, "Received response Pkt %#x with State: %#x Addr: %#x size: %#x\n",
+               pkt, pkt->senderState, pkt->getAddr(), pkt->req->getSize());
         state = dynamic_cast<DmaReqState*>(pkt->senderState);
         pendingCount--;
 
@@ -117,6 +133,7 @@ DmaPort::recvTiming(PacketPtr pkt)
         assert(state);
 
         state->numBytes += pkt->req->getSize();
+        assert(state->totBytes >= state->numBytes);
         if (state->totBytes == state->numBytes) {
             state->completionEvent->process();
             delete state;
@@ -136,7 +153,8 @@ DmaPort::recvTiming(PacketPtr pkt)
 }
 
 DmaDevice::DmaDevice(Params *p)
-    : PioDevice(p), dmaPort(NULL)
+    : PioDevice(p), dmaPort(NULL), minBackoffDelay(p->min_backoff_delay),
+      maxBackoffDelay(p->max_backoff_delay)
 { }
 
 
@@ -165,19 +183,31 @@ DmaPort::drain(Event *de)
 void
 DmaPort::recvRetry()
 {
+    assert(transmitList.size());
     PacketPtr pkt = transmitList.front();
     bool result = true;
-    while (result && transmitList.size()) {
+    do {
         DPRINTF(DMA, "Retry on  Packet %#x with senderState: %#x\n",
                    pkt, pkt->senderState);
         result = sendTiming(pkt);
         if (result) {
             DPRINTF(DMA, "-- Done\n");
             transmitList.pop_front();
+            inRetry = false;
         } else {
+            inRetry = true;
             DPRINTF(DMA, "-- Failed, queued\n");
         }
+    } while (!backoffTime &&  result && transmitList.size());
+
+    if (transmitList.size() && backoffTime && !inRetry) {
+        DPRINTF(DMA, "Scheduling backoff for %d\n", curTick+backoffTime);
+        if (!backoffEvent.scheduled())
+            backoffEvent.schedule(backoffTime+curTick);
     }
+    DPRINTF(DMA, "TransmitList: %d, backoffTime: %d inRetry: %d es: %d\n",
+            transmitList.size(), backoffTime, inRetry,
+            backoffEvent.scheduled());
 }
 
 
@@ -204,33 +234,61 @@ DmaPort::dmaAction(Packet::Command cmd, Addr addr, int size, Event *event,
 
             assert(pendingCount >= 0);
             pendingCount++;
-            sendDma(pkt);
+            queueDma(pkt);
     }
 
 }
 
+void
+DmaPort::queueDma(PacketPtr pkt, bool front)
+{
+
+    if (front)
+        transmitList.push_front(pkt);
+    else
+        transmitList.push_back(pkt);
+    sendDma();
+}
+
 
 void
-DmaPort::sendDma(PacketPtr pkt, bool front)
+DmaPort::sendDma()
 {
     // some kind of selction between access methods
     // more work is going to have to be done to make
     // switching actually work
+    assert(transmitList.size());
+    PacketPtr pkt = transmitList.front();
 
     System::MemoryMode state = sys->getMemoryMode();
     if (state == System::Timing) {
+        if (backoffEvent.scheduled() || inRetry) {
+            DPRINTF(DMA, "Can't send immediately, waiting for retry or backoff timer\n");
+            return;
+        }
+
         DPRINTF(DMA, "Attempting to send Packet %#x with addr: %#x\n",
                 pkt, pkt->getAddr());
-        if (transmitList.size() || !sendTiming(pkt)) {
-            if (front)
-                transmitList.push_front(pkt);
-            else
-                transmitList.push_back(pkt);
-            DPRINTF(DMA, "-- Failed: queued\n");
-        } else {
-            DPRINTF(DMA, "-- Done\n");
+
+        bool result;
+        do {
+            result = sendTiming(pkt);
+            if (result) {
+                transmitList.pop_front();
+                DPRINTF(DMA, "-- Done\n");
+            } else {
+                inRetry = true;
+                DPRINTF(DMA, "-- Failed: queued\n");
+            }
+        } while (result && !backoffTime && transmitList.size());
+
+        if (transmitList.size() && backoffTime && !inRetry &&
+                !backoffEvent.scheduled()) {
+            backoffEvent.schedule(backoffTime+curTick);
         }
     } else if (state == System::Atomic) {
+        transmitList.pop_front();
+
         Tick lat;
         lat = sendAtomic(pkt);
         assert(pkt->senderState);
diff --git a/src/dev/io_device.hh b/src/dev/io_device.hh
index cd7a5296a..bd150bfe4 100644
--- a/src/dev/io_device.hh
+++ b/src/dev/io_device.hh
@@ -107,6 +107,14 @@ class DmaPort : public Port
      * here.*/
     Event *drainEvent;
 
+    /** time to wait between sending another packet, increases as NACKs are
+     * recived, decreases as responses are recived. */
+    Tick backoffTime;
+
+    /** If the port is currently waiting for a retry before it can send whatever
+     * it is that it's sending. */
+    bool inRetry;
+
     virtual bool recvTiming(PacketPtr pkt);
     virtual Tick recvAtomic(PacketPtr pkt)
     { panic("dma port shouldn't be used for pio access."); M5_DUMMY_RETURN }
@@ -122,7 +130,11 @@ class DmaPort : public Port
                                         AddrRangeList &snoop)
     { resp.clear(); snoop.clear(); }
 
-    void sendDma(PacketPtr pkt, bool front = false);
+    void queueDma(PacketPtr pkt, bool front = false);
+    void sendDma();
+
+    /** event to give us a kick every time we backoff time is reached. */
+    EventWrapper<DmaPort, &DmaPort::sendDma> backoffEvent;
 
   public:
     DmaPort(DmaDevice *dev, System *s);
@@ -249,8 +261,17 @@ class BasicPioDevice : public PioDevice
 
 class DmaDevice : public PioDevice
 {
-  protected:
+  public:
+    struct Params :  public PioDevice::Params
+    {
+        Tick min_backoff_delay;
+        Tick max_backoff_delay;
+    };
+
+   protected:
     DmaPort *dmaPort;
+    Tick minBackoffDelay;
+    Tick maxBackoffDelay;
 
   public:
     DmaDevice(Params *p);
diff --git a/src/dev/ns_gige.cc b/src/dev/ns_gige.cc
index 86f56b62e..bec1fb848 100644
--- a/src/dev/ns_gige.cc
+++ b/src/dev/ns_gige.cc
@@ -2812,6 +2812,8 @@ BEGIN_DECLARE_SIM_OBJECT_PARAMS(NSGigE)
 
     SimObjectParam<System *> system;
     SimObjectParam<Platform *> platform;
+    Param<Tick> min_backoff_delay;
+    Param<Tick> max_backoff_delay;
     SimObjectParam<PciConfigData *> configdata;
     Param<uint32_t> pci_bus;
     Param<uint32_t> pci_dev;
@@ -2846,6 +2848,8 @@ BEGIN_INIT_SIM_OBJECT_PARAMS(NSGigE)
 
     INIT_PARAM(system, "System pointer"),
     INIT_PARAM(platform, "Platform pointer"),
+    INIT_PARAM(min_backoff_delay, "Minimum delay after receving a nack packed"),
+    INIT_PARAM(max_backoff_delay, "Maximum delay after receving a nack packed"),
     INIT_PARAM(configdata, "PCI Config data"),
     INIT_PARAM(pci_bus, "PCI bus ID"),
     INIT_PARAM(pci_dev, "PCI device number"),
@@ -2884,6 +2888,8 @@ CREATE_SIM_OBJECT(NSGigE)
     params->name = getInstanceName();
     params->platform = platform;
     params->system = system;
+    params->min_backoff_delay = min_backoff_delay;
+    params->max_backoff_delay = max_backoff_delay;
     params->configData = configdata;
     params->busNum = pci_bus;
     params->deviceNum = pci_dev;
diff --git a/src/dev/pcidev.hh b/src/dev/pcidev.hh
index 56e3ffb4a..5044e2932 100644
--- a/src/dev/pcidev.hh
+++ b/src/dev/pcidev.hh
@@ -105,7 +105,7 @@ class PciDev : public DmaDevice
     };
 
   public:
-    struct Params : public PioDevice::Params
+    struct Params : public DmaDevice::Params
     {
         /**
          * A pointer to the object that contains the first 64 bytes of
diff --git a/src/dev/sinic.cc b/src/dev/sinic.cc
index f61c161aa..1a72652da 100644
--- a/src/dev/sinic.cc
+++ b/src/dev/sinic.cc
@@ -1635,6 +1635,8 @@ BEGIN_DECLARE_SIM_OBJECT_PARAMS_WNS(Sinic, SinicDevice)
 
     SimObjectParam<System *> system;
     SimObjectParam<Platform *> platform;
+    Param<Tick> min_backoff_delay;
+    Param<Tick> max_backoff_delay;
     SimObjectParam<PciConfigData *> configdata;
     Param<uint32_t> pci_bus;
     Param<uint32_t> pci_dev;
@@ -1678,6 +1680,8 @@ BEGIN_INIT_SIM_OBJECT_PARAMS_WNS(Sinic, SinicDevice)
 
     INIT_PARAM(system, "System pointer"),
     INIT_PARAM(platform, "Platform pointer"),
+    INIT_PARAM(min_backoff_delay, "Minimum delay after receving a nack packed"),
+    INIT_PARAM(max_backoff_delay, "Maximum delay after receving a nack packed"),
     INIT_PARAM(configdata, "PCI Config data"),
     INIT_PARAM(pci_bus, "PCI bus ID"),
     INIT_PARAM(pci_dev, "PCI device number"),
@@ -1723,6 +1727,8 @@ CREATE_SIM_OBJECT_WNS(Sinic, SinicDevice)
     params->name = getInstanceName();
     params->platform = platform;
     params->system = system;
+    params->min_backoff_delay = min_backoff_delay;
+    params->max_backoff_delay = max_backoff_delay;
     params->configData = configdata;
     params->busNum = pci_bus;
     params->deviceNum = pci_dev;