mem: Rework the structuring of the prefetchers

Re-organizes the prefetcher class structure. Previously the
BasePrefetcher forced multiple assumptions on the prefetchers that
inherited from it. This patch makes the BasePrefetcher class truly
representative of base functionality. For example, the base class no
longer enforces FIFO order. Instead, prefetchers with FIFO requests
(like the existing stride and tagged prefetchers) now inherit from a
new QueuedPrefetcher base class.

Finally, the stride-based prefetcher now assumes a custimizable lookup table
(sets/ways) rather than the previous fully associative structure.

1 files changed, 5 insertions, 5 deletions

diff --git a/src/mem/cache/cache_impl.hh b/src/mem/cache/cache_impl.hh
index da04cf6f9..15e9bc0fb 100644
--- a/src/mem/cache/cache_impl.hh
+++ b/src/mem/cache/cache_impl.hh
@@ -535,7 +535,7 @@ Cache<TagStore>::recvTimingReq(PacketPtr pkt)
     bool satisfied = access(pkt, blk, lat, writebacks);
 
     // track time of availability of next prefetch, if any
-    Tick next_pf_time = 0;
+    Tick next_pf_time = MaxTick;
 
     bool needsResponse = pkt->needsResponse();
 
@@ -548,7 +548,7 @@ Cache<TagStore>::recvTimingReq(PacketPtr pkt)
 
             // Don't notify on SWPrefetch
             if (!pkt->cmd.isSWPrefetch())
-                next_pf_time = prefetcher->notify(pkt, time);
+                next_pf_time = prefetcher->notify(pkt);
         }
 
         if (needsResponse) {
@@ -648,7 +648,7 @@ Cache<TagStore>::recvTimingReq(PacketPtr pkt)
                 if (prefetcher) {
                     // Don't notify on SWPrefetch
                     if (!pkt->cmd.isSWPrefetch())
-                        next_pf_time = prefetcher->notify(pkt, time);
+                        next_pf_time = prefetcher->notify(pkt);
                 }
             }
         } else {
@@ -688,12 +688,12 @@ Cache<TagStore>::recvTimingReq(PacketPtr pkt)
             if (prefetcher) {
                 // Don't notify on SWPrefetch
                 if (!pkt->cmd.isSWPrefetch())
-                    next_pf_time = prefetcher->notify(pkt, time);
+                    next_pf_time = prefetcher->notify(pkt);
             }
         }
     }
 
-    if (next_pf_time != 0)
+    if (next_pf_time != MaxTick)
         requestMemSideBus(Request_PF, std::max(time, next_pf_time));
 
     // copy writebacks to write buffer