Some more useful debugging info for kernel panic and die events

Increase the default number of CSHR's, we should really fix this or make it a parameter

Use a setBlocked call to tell the bus it should block

New technique for sampling and switchover:
1) Sampler switchover event happens
2) All cpus in the current phase of sampling associated with this sampler are signaled to switchover
3) Each cpu drains it's pipe of things being executed (stops fetching and waits for empty pipe)
4) Once the pipe is empty the cpu calls back to the sampler to signal it has finished, and moves into the switchedout state (continues not to fetch)
5) The sampler collects all the signals, once all cpus are drained it calls the new cpu's in the next phase to takeover from the correct cpu
6) The statistics are reset and the next switchover time is calculated from this point

cpu/base_cpu.cc:
cpu/base_cpu.hh:
cpu/simple_cpu/simple_cpu.cc:
cpu/simple_cpu/simple_cpu.hh:
    Reconfigure the way the sampling switchover works
cpu/pc_event.cc:
    More debugging information on kernel panic's
kern/linux/linux_system.cc:
    More debug info for Kernel Die events
kern/linux/linux_system.hh:
    More debug info for kernel die events

--HG--
extra : convert_revision : 61cc42e43ba738705aa1f1d167b65d4d6dee51ae

7 files changed, 58 insertions, 20 deletions

diff --git a/cpu/base_cpu.cc b/cpu/base_cpu.cc
index 7605ff3c3..58f38d5d5 100644
--- a/cpu/base_cpu.cc
+++ b/cpu/base_cpu.cc
@@ -35,6 +35,7 @@
 #include "base/misc.hh"
 #include "cpu/base_cpu.hh"
 #include "cpu/exec_context.hh"
+#include "cpu/sampling_cpu/sampling_cpu.hh"
 #include "sim/param.hh"
 #include "sim/sim_events.hh"
 
@@ -210,9 +211,10 @@ BaseCPU::registerExecContexts()
 
 
 void
-BaseCPU::switchOut()
+BaseCPU::switchOut(SamplingCPU *sampler)
 {
-    // default: do nothing
+    // default: do nothing, signal done
+    sampler->signalSwitched();
 }
 
 void
diff --git a/cpu/base_cpu.hh b/cpu/base_cpu.hh
index baa956aa8..802da340b 100644
--- a/cpu/base_cpu.hh
+++ b/cpu/base_cpu.hh
@@ -32,6 +32,7 @@
 #include <vector>
 
 #include "base/statistics.hh"
+#include "cpu/sampling_cpu/sampling_cpu.hh"
 #include "sim/eventq.hh"
 #include "sim/sim_object.hh"
 #include "targetarch/isa_traits.hh"
@@ -114,9 +115,9 @@ class BaseCPU : public SimObject
     bool deferRegistration;
     void registerExecContexts();
 
-    /// Prepare for another CPU to take over execution.  Called by
-    /// takeOverFrom() on its argument.
-    virtual void switchOut();
+    /// Prepare for another CPU to take over execution.  When it is
+    /// is ready (drained pipe) it signals the sampler.
+    virtual void switchOut(SamplingCPU *);
 
     /// Take over execution from the given CPU.  Used for warm-up and
     /// sampling.
diff --git a/cpu/pc_event.cc b/cpu/pc_event.cc
index 8f046a7a4..21eef677a 100644
--- a/cpu/pc_event.cc
+++ b/cpu/pc_event.cc
@@ -31,10 +31,11 @@
 #include <string>
 #include <utility>
 
-#include "sim/debug.hh"
+#include "base/trace.hh"
+#include "cpu/base_cpu.hh"
 #include "cpu/exec_context.hh"
 #include "cpu/pc_event.hh"
-#include "base/trace.hh"
+#include "sim/debug.hh"
 #include "sim/universe.hh"
 
 using namespace std;
@@ -123,6 +124,8 @@ BreakPCEvent::BreakPCEvent(PCEventQueue *q, const std::string &desc, bool del)
 void
 BreakPCEvent::process(ExecContext *xc)
 {
+    StringWrap name(xc->cpu->name() + ".break_event");
+    DPRINTFN("break event %s triggered", descr());
     debug_break();
     if (remove)
         delete this;
diff --git a/cpu/simple_cpu/simple_cpu.cc b/cpu/simple_cpu/simple_cpu.cc
index 9f4f821d4..2f1e8e1f1 100644
--- a/cpu/simple_cpu/simple_cpu.cc
+++ b/cpu/simple_cpu/simple_cpu.cc
@@ -47,6 +47,7 @@
 #include "cpu/exec_context.hh"
 #include "cpu/exetrace.hh"
 #include "cpu/full_cpu/smt.hh"
+#include "cpu/sampling_cpu/sampling_cpu.hh"
 #include "cpu/simple_cpu/simple_cpu.hh"
 #include "cpu/static_inst.hh"
 #include "mem/base_mem.hh"
@@ -179,11 +180,21 @@ SimpleCPU::~SimpleCPU()
 }
 
 void
-SimpleCPU::switchOut()
+SimpleCPU::switchOut(SamplingCPU *s)
 {
-    _status = SwitchedOut;
-    if (tickEvent.scheduled())
-        tickEvent.squash();
+    sampler = s;
+    if (status() == DcacheMissStall) {
+        DPRINTF(Sampler,"Outstanding dcache access, waiting for completion\n");
+        _status = DcacheMissSwitch;
+    }
+    else {
+        _status = SwitchedOut;
+
+        if (tickEvent.scheduled())
+            tickEvent.squash();
+
+        sampler->signalSwitched();
+    }
 }
 
 
@@ -203,8 +214,6 @@ SimpleCPU::takeOverFrom(BaseCPU *oldCPU)
             tickEvent.schedule(curTick);
         }
     }
-
-    oldCPU->switchOut();
 }
 
 
@@ -631,6 +640,12 @@ SimpleCPU::processCacheCompletion()
         _status = Running;
         scheduleTickEvent(1);
         break;
+      case DcacheMissSwitch:
+        if (memReq->cmd.isRead()) {
+            curStaticInst->execute(this,traceData);
+        }
+        _status = SwitchedOut;
+        sampler->signalSwitched();
       case SwitchedOut:
         // If this CPU has been switched out due to sampling/warm-up,
         // ignore any further status changes (e.g., due to cache
diff --git a/cpu/simple_cpu/simple_cpu.hh b/cpu/simple_cpu/simple_cpu.hh
index 8104d73a4..85bd1a74f 100644
--- a/cpu/simple_cpu/simple_cpu.hh
+++ b/cpu/simple_cpu/simple_cpu.hh
@@ -29,12 +29,13 @@
 #ifndef __SIMPLE_CPU_HH__
 #define __SIMPLE_CPU_HH__
 
-#include "cpu/base_cpu.hh"
-#include "sim/eventq.hh"
-#include "cpu/pc_event.hh"
 #include "base/statistics.hh"
+#include "cpu/base_cpu.hh"
 #include "cpu/exec_context.hh"
+#include "cpu/pc_event.hh"
+#include "cpu/sampling_cpu/sampling_cpu.hh"
 #include "cpu/static_inst.hh"
+#include "sim/eventq.hh"
 
 // forward declarations
 #ifdef FULL_SYSTEM
@@ -117,6 +118,7 @@ class SimpleCPU : public BaseCPU
         IcacheMissStall,
         IcacheMissComplete,
         DcacheMissStall,
+        DcacheMissSwitch,
         SwitchedOut
     };
 
@@ -163,7 +165,7 @@ class SimpleCPU : public BaseCPU
     // execution context
     ExecContext *xc;
 
-    void switchOut();
+    void switchOut(SamplingCPU *s);
     void takeOverFrom(BaseCPU *oldCPU);
 
 #ifdef FULL_SYSTEM
@@ -184,6 +186,11 @@ class SimpleCPU : public BaseCPU
     // Refcounted pointer to the one memory request.
     MemReqPtr memReq;
 
+    // Pointer to the sampler that is telling us to switchover.
+    // Used to signal the completion of the pipe drain and schedule
+    // the next switchover
+    SamplingCPU *sampler;
+
     StaticInstPtr<TheISA> curStaticInst;
 
     class CacheCompletionEvent : public Event
diff --git a/kern/linux/linux_system.cc b/kern/linux/linux_system.cc
index 401b4ef44..4ac03143e 100644
--- a/kern/linux/linux_system.cc
+++ b/kern/linux/linux_system.cc
@@ -102,12 +102,19 @@ LinuxSystem::LinuxSystem(Params *p)
     } else
         panic("could not find dp264_mv\n");
 
-#ifdef DEBUG
+#ifndef NDEBUG
     kernelPanicEvent = new BreakPCEvent(&pcEventQueue, "kernel panic");
     if (kernelSymtab->findAddress("panic", addr))
         kernelPanicEvent->schedule(addr);
     else
         panic("could not find kernel symbol \'panic\'");
+
+    kernelDieEvent = new BreakPCEvent(&pcEventQueue, "die if kernel");
+    if (kernelSymtab->findAddress("die_if_kernel", addr))
+        kernelDieEvent->schedule(addr);
+    else
+        panic("could not find kernel symbol \'die_if_kernel\'");
+
 #endif
 
     /**
@@ -174,7 +181,7 @@ LinuxSystem::LinuxSystem(Params *p)
 
 LinuxSystem::~LinuxSystem()
 {
-#ifdef DEBUG
+#ifndef NDEBUG
     delete kernelPanicEvent;
 #endif
     delete skipIdeDelay50msEvent;
diff --git a/kern/linux/linux_system.hh b/kern/linux/linux_system.hh
index 5e3cba9b3..905b0ee70 100644
--- a/kern/linux/linux_system.hh
+++ b/kern/linux/linux_system.hh
@@ -57,9 +57,12 @@ class PrintThreadInfo;
 class LinuxSystem : public System
 {
   private:
-#ifdef DEBUG
+#ifndef NDEBUG
     /** Event to halt the simulator if the kernel calls panic()  */
     BreakPCEvent *kernelPanicEvent;
+
+    /** Event to halt the simulator if the kernel calls die_if_kernel  */
+    BreakPCEvent *kernelDieEvent;
 #endif
 
     /**