pwr: Adds logic to enter power gating for the cpu model

[gem5.git] / src / cpu / simple / atomic.cc

diff --git a/src/cpu/simple/atomic.cc b/src/cpu/simple/atomic.cc
index c09f0c52635cebc03c9535bf029638fbbc5ab52c..9039e6137b1d3164e7f3b524c13a17d1fe4483e3 100644 (file)
--- a/src/cpu/simple/atomic.cc
+++ b/src/cpu/simple/atomic.cc
@@ -1,6 +1,6 @@
 /*
  * Copyright 2014 Google, Inc.
- * Copyright (c) 2012-2013,2015 ARM Limited
+ * Copyright (c) 2012-2013,2015,2017 ARM Limited
  * All rights reserved.
  *
  * The license below extends only to copyright in the software and shall
@@ -64,24 +64,6 @@
 using namespace std;
 using namespace TheISA;
 
-AtomicSimpleCPU::TickEvent::TickEvent(AtomicSimpleCPU *c)
-    : Event(CPU_Tick_Pri), cpu(c)
-{
-}
-
-
-void
-AtomicSimpleCPU::TickEvent::process()
-{
-    cpu->tick();
-}
-
-const char *
-AtomicSimpleCPU::TickEvent::description() const
-{
-    return "AtomicSimpleCPU tick";
-}
-
 void
 AtomicSimpleCPU::init()
 {
@@ -94,7 +76,10 @@ AtomicSimpleCPU::init()
 }
 
 AtomicSimpleCPU::AtomicSimpleCPU(AtomicSimpleCPUParams *p)
-    : BaseSimpleCPU(p), tickEvent(this), width(p->width), locked(false),
+    : BaseSimpleCPU(p),
+      tickEvent([this]{ tick(); }, "AtomicSimpleCPU tick",
+                false, Event::CPU_Tick_Pri),
+      width(p->width), locked(false),
       simulate_data_stalls(p->simulate_data_stalls),
       simulate_inst_stalls(p->simulate_inst_stalls),
       icachePort(name() + ".icache_port", this),
@@ -116,6 +101,9 @@ AtomicSimpleCPU::~AtomicSimpleCPU()
 DrainState
 AtomicSimpleCPU::drain()
 {
+    // Deschedule any power gating event (if any)
+    deschedulePowerGatingEvent();
+
     if (switchedOut())
         return DrainState::Drained;
 
@@ -178,6 +166,9 @@ AtomicSimpleCPU::drainResume()
             threadInfo[tid]->notIdleFraction = 0;
         }
     }
+
+    // Reschedule any power gating event (if any)
+    schedulePowerGatingEvent();
 }
 
 bool
@@ -628,6 +619,7 @@ AtomicSimpleCPU::tick()
 
             preExecute();
 
+            Tick stall_ticks = 0;
             if (curStaticInst) {
                 fault = curStaticInst->execute(&t_info, traceData);
 
@@ -641,6 +633,13 @@ AtomicSimpleCPU::tick()
                     traceData = NULL;
                 }
 
+                if (dynamic_pointer_cast<SyscallRetryFault>(fault)) {
+                    // Retry execution of system calls after a delay.
+                    // Prevents immediate re-execution since conditions which
+                    // caused the retry are unlikely to change every tick.
+                    stall_ticks += clockEdge(syscallRetryLatency) - curTick();
+                }
+
                 postExecute();
             }
 
@@ -649,7 +648,6 @@ AtomicSimpleCPU::tick()
                         curStaticInst->isFirstMicroop()))
                 instCnt++;
 
-            Tick stall_ticks = 0;
             if (simulate_inst_stalls && icache_access)
                 stall_ticks += icache_latency;