mem: Delay servicing an MSHR after its allocation

An MSHR is allocated and the computed latency determines when the MSHR
will be ready and can be serviced by the cache. This patch adds a
function that allows changing the time that an MSHR is ready and
adjusts the queue such that other MSHRs can be serviced first if they
are ready.

Change-Id: Ie908191fcb3c2d84d4c6f855c8b1e41ca5881bff
Reviewed-on: https://gem5-review.googlesource.com/c/12906
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/src/mem/cache/mshr.hh b/src/mem/cache/mshr.hh
index 56b81b6b2..b94dfb9c5 100644
--- a/src/mem/cache/mshr.hh
+++ b/src/mem/cache/mshr.hh
@@ -514,6 +514,16 @@ class MSHR : public QueueEntry, public Printable
     bool trySatisfyFunctional(PacketPtr pkt);
 
     /**
+     * Adds a delay relative to the current tick to the current MSHR
+     * @param delay_ticks the desired delay in ticks
+     */
+    void delay(Tick delay_ticks)
+    {
+        assert(readyTime <= curTick());
+        readyTime = curTick() + delay_ticks;
+    }
+
+    /**
      * Prints the contents of this MSHR for debugging.
      */
     void print(std::ostream &os,