cpu: Fix cache blocked load behavior in o3 cpu

This patch fixes the load blocked/replay mechanism in the o3 cpu.  Rather than
flushing the entire pipeline, this patch replays loads once the cache becomes
unblocked.

Additionally, deferred memory instructions (loads which had conflicting stores),
when replayed would not respect the number of functional units (only respected
issue width).  This patch also corrects that.

Improvements over 20% have been observed on a microbenchmark designed to
exercise this behavior.

1 files changed, 1 insertions, 26 deletions

diff --git a/src/cpu/o3/lsq.hh b/src/cpu/o3/lsq.hh
index e0ed05d7e..5d57bb52b 100644
--- a/src/cpu/o3/lsq.hh
+++ b/src/cpu/o3/lsq.hh
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2011-2012 ARM Limited
+ * Copyright (c) 2011-2012, 2014 ARM Limited
  * Copyright (c) 2013 Advanced Micro Devices, Inc.
  * All rights reserved
  *
@@ -151,18 +151,6 @@ class LSQ {
     bool violation(ThreadID tid)
     { return thread[tid].violation(); }
 
-    /** Returns if a load is blocked due to the memory system for a specific
-     *  thread.
-     */
-    bool loadBlocked(ThreadID tid)
-    { return thread[tid].loadBlocked(); }
-
-    bool isLoadBlockedHandled(ThreadID tid)
-    { return thread[tid].isLoadBlockedHandled(); }
-
-    void setLoadBlockedHandled(ThreadID tid)
-    { thread[tid].setLoadBlockedHandled(); }
-
     /** Gets the instruction that caused the memory ordering violation. */
     DynInstPtr getMemDepViolator(ThreadID tid)
     { return thread[tid].getMemDepViolator(); }
@@ -277,15 +265,6 @@ class LSQ {
     bool willWB(ThreadID tid)
     { return thread[tid].willWB(); }
 
-    /** Returns if the cache is currently blocked. */
-    bool cacheBlocked() const
-    { return retryTid != InvalidThreadID; }
-
-    /** Sets the retry thread id, indicating that one of the LSQUnits
-     * tried to access the cache but the cache was blocked. */
-    void setRetryTid(ThreadID tid)
-    { retryTid = tid; }
-
     /** Debugging function to print out all instructions. */
     void dumpInsts() const;
     /** Debugging function to print out instructions from a specific thread. */
@@ -348,10 +327,6 @@ class LSQ {
 
     /** Number of Threads. */
     ThreadID numThreads;
-
-    /** The thread id of the LSQ Unit that is currently waiting for a
-     * retry. */
-    ThreadID retryTid;
 };
 
 template <class Impl>