From 187dcb18bfd87db63ad914d2ba04f0bd2dc0637d Mon Sep 17 00:00:00 2001
From: Gabe Black <gblack@eecs.umich.edu>
Date: Mon, 9 Oct 2006 18:12:45 -0400
Subject: [PATCH] Potentially functional partially timed bandwidth limitted bus
 model.

src/mem/bus.cc:
    Fixes to the previous hand merging, and put the snooping back into recvTiming and out of it's own function.
src/mem/bus.hh:
    Put snooping back into recvTiming and not in it's own function.

--HG--
extra : convert_revision : fd031b7e6051a5be07ed6926454fde73b1739dc6
---
 src/mem/bus.cc | 61 +++++++++++++++++++++++++++-----------------------
 src/mem/bus.hh |  9 --------
 2 files changed, 33 insertions(+), 37 deletions(-)

diff --git a/src/mem/bus.cc b/src/mem/bus.cc
index df85ee0d9..c288e34c0 100644
--- a/src/mem/bus.cc
+++ b/src/mem/bus.cc
@@ -118,25 +118,26 @@ Bus::recvTiming(Packet *pkt)
     DPRINTF(Bus, "recvTiming: packet src %d dest %d addr 0x%x cmd %s\n",
             pkt->getSrc(), pkt->getDest(), pkt->getAddr(), pkt->cmdString());
 
+    Port *pktPort = interfaces[pkt->getSrc()];
+
     short dest = pkt->getDest();
     if (dest == Packet::Broadcast) {
-        if ( timingSnoopPhase1(pkt) )
-        if (timingSnoop(pkt))
-        {
-            timingSnoopPhase2(pkt);
+        if (timingSnoop(pkt)) {
             pkt->flags |= SNOOP_COMMIT;
             bool success = timingSnoop(pkt);
             assert(success);
             if (pkt->flags & SATISFIED) {
                 //Cache-Cache transfer occuring
+                if (retryingPort) {
+                    retryList.pop_front();
+                    retryingPort = NULL;
+                }
                 return true;
             }
             port = findPort(pkt->getAddr(), pkt->getSrc());
-        }
-        else
-        {
+        } else {
             //Snoop didn't succeed
-            retryList.push_back(interfaces[pkt->getSrc()]);
+            addToRetryList(pktPort);
             return false;
         }
     } else {
@@ -144,6 +145,30 @@ Bus::recvTiming(Packet *pkt)
         assert(dest != pkt->getSrc()); // catch infinite loops
         port = interfaces[dest];
     }
+
+    // The packet will be sent. Figure out how long it occupies the bus.
+    int numCycles = 0;
+    // Requests need one cycle to send an address
+    if (pkt->isRequest())
+        numCycles++;
+    else if (pkt->isResponse() || pkt->hasData()) {
+        // If a packet has data, it needs ceil(size/width) cycles to send it
+        // We're using the "adding instead of dividing" trick again here
+        if (pkt->hasData()) {
+            int dataSize = pkt->getSize();
+            for (int transmitted = 0; transmitted < dataSize;
+                    transmitted += width) {
+                numCycles++;
+            }
+        } else {
+            // If the packet didn't have data, it must have been a response.
+            // Those use the bus for one cycle to send their data.
+            numCycles++;
+        }
+    }
+
+    occupyBus(numCycles);
+
     if (port->sendTiming(pkt))  {
         // Packet was successfully sent. Return true.
         // Also take care of retries
@@ -175,26 +200,6 @@ Bus::recvRetry(int id)
     }
 }
 
-Port *
-Bus::findDestPort(PacketPtr pkt, int id)
-{
-    Port * port = NULL;
-    short dest = pkt->getDest();
-
-    if (dest == Packet::Broadcast) {
-        if (timingSnoopPhase1(pkt)) {
-            timingSnoopPhase2(pkt);
-            port = findPort(pkt->getAddr(), pkt->getSrc());
-        }
-        //else, port stays NULL
-    } else {
-        assert(dest >= 0 && dest < interfaces.size());
-        assert(dest != pkt->getSrc()); // catch infinite loops
-        port = interfaces[dest];
-    }
-    return port;
-}
-
 Port *
 Bus::findPort(Addr addr, int id)
 {
diff --git a/src/mem/bus.hh b/src/mem/bus.hh
index f8a006911..c9b0a76a0 100644
--- a/src/mem/bus.hh
+++ b/src/mem/bus.hh
@@ -97,15 +97,6 @@ class Bus : public MemObject
      */
     Port *findPort(Addr addr, int id);
 
-    /** Finds the port a packet should be sent to. If the bus is blocked, no port
-     * is returned.
-     * @param pkt Packet to find a destination port for.
-     * @param id Id of the port this packet was received from
-     *           (to prevent loops)
-     */
-
-    Port *findDestPort(PacketPtr pkt, int id);
-
     /** Find all ports with a matching snoop range, except src port.  Keep in mind
      * that the ranges shouldn't overlap or you will get a double snoop to the same
      * interface.and the cache will assert out.