inorder: initialize res. req. vectors based on resource bandwidth

first change in an optimization that will stop InOrder from allocating new memory for every instruction's
request to a resource. This gets expensive since every instruction needs to access ~10 requests before
graduation. Instead, the plan is to allocate just enough resource request objects to satisfy each resource's
bandwidth (e.g. the execution unit would need to allocate 3 resource request objects for a 1-issue pipeline
since on any given cycle it could have 2 read requests and 1 write request) and then let the instructions
contend and reuse those allocated requests. The end result is a smaller memory footprint for the InOrder model
and increased simulation performance

1 files changed, 6 insertions, 0 deletions

diff --git a/src/cpu/inorder/resource.cc b/src/cpu/inorder/resource.cc
index 72b45dda8..5a31125c6 100644
--- a/src/cpu/inorder/resource.cc
+++ b/src/cpu/inorder/resource.cc
@@ -40,6 +40,8 @@ Resource::Resource(string res_name, int res_id, int res_width,
     : resName(res_name), id(res_id),
       width(res_width), latency(res_latency), cpu(_cpu)
 {
+    reqs.resize(width);
+
     // Use to deny a instruction a resource.
     deniedReq = new ResourceRequest(this, NULL, 0, 0, 0, 0);
 }
@@ -57,6 +59,10 @@ Resource::init()
     // Set Up Resource Events to Appropriate Resource BandWidth
     resourceEvent = new ResourceEvent[width];
 
+    for (int i = 0; i < width; i++) {
+        reqs[i] = new ResourceRequest(this, NULL, 0, 0, 0, 0);
+    }
+
     initSlots();
 }