/*
- * Copyright (c) 2012 ARM Limited
+ * Copyright (c) 2012-2013, 2015-2016 ARM Limited
+ * Copyright (c) 2013 Cornell University
* All rights reserved
*
* The license below extends only to copyright in the software and shall
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- * Authors: Andreas Hansson
*/
/**
#ifndef __SIM_CLOCKED_OBJECT_HH__
#define __SIM_CLOCKED_OBJECT_HH__
+#include "base/callback.hh"
#include "base/intmath.hh"
-#include "base/misc.hh"
+#include "enums/PwrState.hh"
#include "params/ClockedObject.hh"
#include "sim/core.hh"
+#include "sim/clock_domain.hh"
#include "sim/sim_object.hh"
/**
- * The ClockedObject class extends the SimObject with a clock and
- * accessor functions to relate ticks to the cycles of the object.
+ * Helper class for objects that need to be clocked. Clocked objects
+ * typically inherit from this class. Objects that need SimObject
+ * functionality as well should inherit from ClockedObject.
*/
-class ClockedObject : public SimObject
+class Clocked
{
private:
-
// the tick value of the next clock edge (>= curTick()) at the
// time of the last call to update()
mutable Tick tick;
mutable Cycles cycle;
/**
- * Prevent inadvertent use of the copy constructor and assignment
- * operator by making them private.
- */
- ClockedObject(ClockedObject&);
- ClockedObject& operator=(ClockedObject&);
-
- /**
- * Align cycle and tick to the next clock edge if not already done.
+ * Align cycle and tick to the next clock edge if not already done. When
+ * complete, tick must be at least curTick().
*/
- void update() const
+ void
+ update() const
{
// both tick and cycle are up-to-date and we are done, note
// that the >= is important as it captures cases where tick
// optimise for the common case and see if the tick should be
// advanced by a single clock period
- tick += clock;
+ tick += clockPeriod();
++cycle;
// see if we are done at this point
// if not, we have to recalculate the cycle and tick, we
// perform the calculations in terms of relative cycles to
// allow changes to the clock period in the future
- Cycles elapsedCycles(divCeil(curTick() - tick, clock));
+ Cycles elapsedCycles(divCeil(curTick() - tick, clockPeriod()));
cycle += elapsedCycles;
- tick += elapsedCycles * clock;
+ tick += elapsedCycles * clockPeriod();
}
- // Clock period in ticks
- Tick clock;
+ /**
+ * The clock domain this clocked object belongs to
+ */
+ ClockDomain &clockDomain;
protected:
/**
- * Create a clocked object and set the clock based on the
+ * Create a clocked object and set the clock domain based on the
* parameters.
*/
- ClockedObject(const ClockedObjectParams* p) :
- SimObject(p), tick(0), cycle(0), clock(p->clock)
+ Clocked(ClockDomain &clk_domain)
+ : tick(0), cycle(0), clockDomain(clk_domain)
{
- if (clock == 0) {
- fatal("%s has a clock period of zero\n", name());
- }
+ // Register with the clock domain, so that if the clock domain
+ // frequency changes, we can update this object's tick.
+ clockDomain.registerWithClockDomain(this);
}
+ Clocked(Clocked &) = delete;
+ Clocked &operator=(Clocked &) = delete;
+
/**
* Virtual destructor due to inheritance.
*/
- virtual ~ClockedObject() { }
+ virtual ~Clocked() { }
/**
* Reset the object's clock using the current global tick value. Likely
* to be used only when the global clock is reset. Currently, this done
* only when Ruby is done warming up the memory system.
*/
- void resetClock() const
+ void
+ resetClock() const
{
- Cycles elapsedCycles(divCeil(curTick(), clock));
+ Cycles elapsedCycles(divCeil(curTick(), clockPeriod()));
cycle = elapsedCycles;
- tick = elapsedCycles * clock;
+ tick = elapsedCycles * clockPeriod();
}
+ /**
+ * A hook subclasses can implement so they can do any extra work that's
+ * needed when the clock rate is changed.
+ */
+ virtual void clockPeriodUpdated() {}
+
public:
/**
- * Determine the tick when a cycle begins, by default the current
- * one, but the argument also enables the caller to determine a
- * future cycle.
+ * Update the tick to the current tick.
+ */
+ void
+ updateClockPeriod()
+ {
+ update();
+ clockPeriodUpdated();
+ }
+
+ /**
+ * Determine the tick when a cycle begins, by default the current one, but
+ * the argument also enables the caller to determine a future cycle. When
+ * curTick() is on a clock edge, the number of cycles in the parameter is
+ * added to curTick() to be returned. When curTick() is not aligned to a
+ * clock edge, the number of cycles in the parameter is added to the next
+ * clock edge.
*
* @param cycles The number of cycles into the future
*
- * @return The tick when the clock edge occurs
+ * @return The start tick when the requested clock edge occurs. Precisely,
+ * this tick can be
+ * curTick() + [0, clockPeriod()) + clockPeriod() * cycles
*/
- inline Tick clockEdge(Cycles cycles = Cycles(0)) const
+ Tick
+ clockEdge(Cycles cycles=Cycles(0)) const
{
// align tick to the next clock edge
update();
// figure out when this future cycle is
- return tick + clock * cycles;
+ return tick + clockPeriod() * cycles;
}
/**
* Determine the current cycle, corresponding to a tick aligned to
* a clock edge.
*
- * @return The current cycle count
+ * @return When curTick() is on a clock edge, return the Cycle corresponding
+ * to that clock edge. When curTick() is not on a clock edge, return the
+ * Cycle corresponding to the next clock edge.
*/
- inline Cycles curCycle() const
+ Cycles
+ curCycle() const
{
// align cycle to the next clock edge.
update();
}
/**
- * Based on the clock of the object, determine the tick when the
- * next cycle begins, in other words, return the next clock edge.
+ * Based on the clock of the object, determine the start tick of the first
+ * cycle that is at least one cycle in the future. When curTick() is at the
+ * current cycle edge, this returns the next clock edge. When calling this
+ * during the middle of a cycle, this returns 2 clock edges in the future.
*
- * @return The tick when the next cycle starts
+ * @return The start tick of the first cycle that is at least one cycle in
+ * the future. Precisely, the returned tick can be in the range
+ * curTick() + [clockPeriod(), 2 * clockPeriod())
*/
- Tick nextCycle() const
- { return clockEdge(); }
+ Tick nextCycle() const { return clockEdge(Cycles(1)); }
+
+ uint64_t frequency() const { return SimClock::Frequency / clockPeriod(); }
- inline uint64_t frequency() const { return SimClock::Frequency / clock; }
+ Tick clockPeriod() const { return clockDomain.clockPeriod(); }
+
+ double voltage() const { return clockDomain.voltage(); }
+
+ Cycles
+ ticksToCycles(Tick t) const
+ {
+ return Cycles(divCeil(t, clockPeriod()));
+ }
+
+ Tick cyclesToTicks(Cycles c) const { return clockPeriod() * c; }
+};
- inline Tick clockPeriod() const { return clock; }
+/**
+ * The ClockedObject class extends the SimObject with a clock and
+ * accessor functions to relate ticks to the cycles of the object.
+ */
+class ClockedObject : public SimObject, public Clocked
+{
+ public:
+ ClockedObject(const ClockedObjectParams *p);
+
+ /** Parameters of ClockedObject */
+ typedef ClockedObjectParams Params;
+ const Params *
+ params() const
+ {
+ return reinterpret_cast<const Params*>(_params);
+ }
+
+ void serialize(CheckpointOut &cp) const override;
+ void unserialize(CheckpointIn &cp) override;
+
+ Enums::PwrState pwrState() const { return _currPwrState; }
+
+ std::string
+ pwrStateName() const
+ {
+ return Enums::PwrStateStrings[_currPwrState];
+ }
+
+ /** Returns the percentage residency for each power state */
+ std::vector<double> pwrStateWeights() const;
+
+ /**
+ * Record stats values like state residency by computing the time
+ * difference from previous update. Also, updates the previous evaluation
+ * tick once all stats are recorded.
+ * Usually called on power state change and stats dump callback.
+ */
+ void computeStats();
+
+ void pwrState(Enums::PwrState);
+
+ protected:
+
+ /** To keep track of the current power state */
+ Enums::PwrState _currPwrState;
+
+ Tick prvEvalTick;
+
+ struct ClockedObjectStats : public Stats::Group
+ {
+ ClockedObjectStats(ClockedObject &co);
- inline Cycles ticksToCycles(Tick tick) const
- { return Cycles(tick / clock); }
+ void regStats() override;
+ void preDumpStats() override;
+ ClockedObject &clockedObject;
+ Stats::Scalar numPwrStateTransitions;
+ Stats::Distribution pwrStateClkGateDist;
+ Stats::Vector pwrStateResidencyTicks;
+ } stats;
};
#endif //__SIM_CLOCKED_OBJECT_HH__
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