src/sim/dvfs_handler.hh - public/gem5 - Git at Google

 /*
  * Copyright (c) 2013-2014 ARM Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
  * not be construed as granting a license to any other intellectual
  * property including but not limited to intellectual property relating
  * to a hardware implementation of the functionality of the software
  * licensed hereunder.  You may use the software subject to the license
  * terms below provided that you ensure that this notice is replicated
  * unmodified and in its entirety in all distributions of the software,
  * modified or unmodified, in source code or in binary form.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met: redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer;
  * redistributions in binary form must reproduce the above copyright
  * notice, this list of conditions and the following disclaimer in the
  * documentation and/or other materials provided with the distribution;
  * neither the name of the copyright holders nor the names of its
  * contributors may be used to endorse or promote products derived from
  * this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * 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.
  */

 /**
  * @file
  * DVFSHandler and DomainConfig class declaration used for managing voltage
  * and frequency scaling of the various DVFS domains in the system (with each
  * domain having their independent domain configuration information)
  */


 #ifndef __SIM_DVFS_HANDLER_HH__
 #define __SIM_DVFS_HANDLER_HH__

 #include <cassert>
 #include <map>
 #include <vector>

 #include "base/logging.hh"
 #include "base/types.hh"
 #include "debug/DVFS.hh"
 #include "params/DVFSHandler.hh"
 #include "sim/clock_domain.hh"
 #include "sim/eventq.hh"
 #include "sim/sim_object.hh"

 namespace gem5
 {

 /**
  * DVFS Handler class, maintains a list of all the domains it can handle.
  * Each entry of that list is an object of the DomainConfig class, and the
  * handler uses the methods provided by that class to get access to the
  * configuration of each domain. The handler is responsible for setting/getting
  * clock periods and voltages from clock/voltage domains.
  * The handler acts the bridge between software configurable information
  * for each domain as provided to the controller and the hardware
  * implementation details for those domains.
  */
 class DVFSHandler : public SimObject
 {
   public:
     typedef DVFSHandlerParams Params;
     DVFSHandler(const Params &p);

     typedef SrcClockDomain::DomainID DomainID;
     typedef SrcClockDomain::PerfLevel PerfLevel;

     /**
      * Get the number of domains assigned to this DVFS handler.
      * @return Number of domains
      */
     uint32_t numDomains() const { return domainIDList.size(); }

     /**
      * Get the n-th domain ID, from the domains managed by this handler.
      * @return Domain ID
      */
     DomainID domainID(uint32_t index) const;

     /**
      * Check whether a domain ID is known to the handler or not.
      * @param domain_id Domain ID to check
      * @return Domain ID known to handler?
      */
     bool validDomainID(DomainID domain_id) const;

     /**
      * Get transition latency to switch between performance levels.
      * @return Transition latency
      */
     Tick transLatency() const { return _transLatency; }

     /**
      * Set a new performance level for the specified domain.  The actual update
      * will be delayed by transLatency().
      *
      * @param domain_id Software visible ID of the domain to be configured
      * @param perf_level Requested performance level (0 - fast, >0 slower)
      * @return status whether the setting was successful
      */
     bool perfLevel(DomainID domain_id, PerfLevel perf_level);

     /**
      * Get the current performance level of a domain.  While a change request is
      * in-flight, will return the current (i.e. old, unmodified) value.
      *
      * @param domain_id Domain ID to query
      * @return Current performance level of the specified domain
      */
     PerfLevel perfLevel(DomainID domain_id) const {
          assert(isEnabled());
          return findDomain(domain_id)->perfLevel();
     }

     /**
      * Read the clock period of the specified domain at the specified
      * performance level.
      * @param domain_id Domain ID to query
      * @param perf_level Performance level of interest
      * @return Clock period in ticks for the requested performance level of
      * the respective domain
      */
     Tick clkPeriodAtPerfLevel(DomainID domain_id, PerfLevel perf_level) const
     {
         SrcClockDomain *d = findDomain(domain_id);
         assert(d);
         PerfLevel n = d->numPerfLevels();
         if (perf_level < n)
             return d->clkPeriodAtPerfLevel(perf_level);

         warn("DVFSHandler %s reads illegal frequency level %u from "\
              "SrcClockDomain %s. Returning 0\n", name(), perf_level, d->name());
         return Tick(0);
     }

     /**
      * Read the voltage of the specified domain at the specified
      * performance level.
      * @param domain_id Domain ID to query
      * @param perf_level Performance level of interest
      * @return Voltage for the requested performance level of the respective
      * domain
      */
     double voltageAtPerfLevel(DomainID domain_id, PerfLevel perf_level) const;

     /**
      * Get the total number of available performance levels.
      *
      * @param domain_id Domain ID to query
      * @return Number of performance levels that where configured for the
      * respective domain
      */
     PerfLevel numPerfLevels(PerfLevel domain_id) const
     {
         return findDomain(domain_id)->numPerfLevels();
     }

     /**
      * Check enable status of the DVFS handler, when the handler is disabled, no
      * request should be sent to the handler.
      * @return True, if the handler is enabled
      */
     bool isEnabled() const { return enableHandler; }

     void serialize(CheckpointOut &cp) const override;
     void unserialize(CheckpointIn &cp) override;

   private:
     typedef std::map<DomainID, SrcClockDomain*> Domains;
     Domains domains;

     /**
       * List of IDs avaiable in the domain list
       */
     std::vector<DomainID> domainIDList;

     /**
       * Clock domain of the system the handler is instantiated.
       */
     SrcClockDomain* sysClkDomain;

     /**
      * Search for a domain based on the domain ID.
      *
      * @param domain_id Domain ID to search for
      * @return Pointer to the source clock domain with matching ID.
      */
     SrcClockDomain *findDomain(DomainID domain_id) const {
         auto it = domains.find(domain_id);
         panic_if(it == domains.end(),
                  "DVFS: Could not find a domain for ID %d.\n",domain_id );
         return domains.find(domain_id)->second;
     }

     /**
      * Disabling the DVFS handler ensures that all the DVFS migration requests
      * are ignored. Domains remain at their default frequency and voltage.
      */
     bool enableHandler;


     /**
      * This corresponds to the maximum transition latency associated with the
      * hardware transitioning from a particular performance level to the other
      */
     const Tick _transLatency;


     /**
      * Update performance level event, encapsulates all the required information
      * for a future call to change a domain's performance level.
      */
     struct UpdateEvent : public Event
     {
         UpdateEvent() : Event(DVFS_Update_Pri), domainIDToSet(0),
                         perfLevelToSet(0) {}

         /**
          * Static pointer to the single DVFS hander for all the update events
          */
         static DVFSHandler *dvfsHandler;

         /**
          * ID of the domain that will be changed by the in-flight event
          */
         DomainID domainIDToSet;

         /**
          * Target performance level of the in-flight event
          */
         PerfLevel perfLevelToSet;

         /**
          * Updates the performance level by modifying the clock and the voltage
          * of the associated clocked objects.  Gets information from
          * domainIDToSet and perfLevelToSet for easier calling through an
          * event.
          */
         void updatePerfLevel();

         void process() { updatePerfLevel(); }
     };

     typedef std::map<DomainID, UpdateEvent> UpdatePerfLevelEvents;
     /**
      * Map from domain IDs -> perf level update events, records in-flight change
      * requests per domain ID.
      */
     UpdatePerfLevelEvents updatePerfLevelEvents;
 };

 } // namespace gem5

 #endif // __SIM_DVFS_HANDLER_HH__
	/*
	* Copyright (c) 2013-2014 ARM Limited
	* All rights reserved
	*
	* The license below extends only to copyright in the software and shall
	* not be construed as granting a license to any other intellectual
	* property including but not limited to intellectual property relating
	* to a hardware implementation of the functionality of the software
	* licensed hereunder. You may use the software subject to the license
	* terms below provided that you ensure that this notice is replicated
	* unmodified and in its entirety in all distributions of the software,
	* modified or unmodified, in source code or in binary form.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are
	* met: redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer;
	* redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution;
	* neither the name of the copyright holders nor the names of its
	* contributors may be used to endorse or promote products derived from
	* this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* 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.
	*/

	/**
	* @file
	* DVFSHandler and DomainConfig class declaration used for managing voltage
	* and frequency scaling of the various DVFS domains in the system (with each
	* domain having their independent domain configuration information)
	*/


	#ifndef __SIM_DVFS_HANDLER_HH__
	#define __SIM_DVFS_HANDLER_HH__

	#include <cassert>
	#include <map>
	#include <vector>

	#include "base/logging.hh"
	#include "base/types.hh"
	#include "debug/DVFS.hh"
	#include "params/DVFSHandler.hh"
	#include "sim/clock_domain.hh"
	#include "sim/eventq.hh"
	#include "sim/sim_object.hh"

	namespace gem5
	{

	/**
	* DVFS Handler class, maintains a list of all the domains it can handle.
	* Each entry of that list is an object of the DomainConfig class, and the
	* handler uses the methods provided by that class to get access to the
	* configuration of each domain. The handler is responsible for setting/getting
	* clock periods and voltages from clock/voltage domains.
	* The handler acts the bridge between software configurable information
	* for each domain as provided to the controller and the hardware
	* implementation details for those domains.
	*/
	class DVFSHandler : public SimObject
	{
	public:
	typedef DVFSHandlerParams Params;
	DVFSHandler(const Params &p);

	typedef SrcClockDomain::DomainID DomainID;
	typedef SrcClockDomain::PerfLevel PerfLevel;

	/**
	* Get the number of domains assigned to this DVFS handler.
	* @return Number of domains
	*/
	uint32_t numDomains() const { return domainIDList.size(); }

	/**
	* Get the n-th domain ID, from the domains managed by this handler.
	* @return Domain ID
	*/
	DomainID domainID(uint32_t index) const;

	/**
	* Check whether a domain ID is known to the handler or not.
	* @param domain_id Domain ID to check
	* @return Domain ID known to handler?
	*/
	bool validDomainID(DomainID domain_id) const;

	/**
	* Get transition latency to switch between performance levels.
	* @return Transition latency
	*/
	Tick transLatency() const { return _transLatency; }

	/**
	* Set a new performance level for the specified domain. The actual update
	* will be delayed by transLatency().
	*
	* @param domain_id Software visible ID of the domain to be configured
	* @param perf_level Requested performance level (0 - fast, >0 slower)
	* @return status whether the setting was successful
	*/
	bool perfLevel(DomainID domain_id, PerfLevel perf_level);

	/**
	* Get the current performance level of a domain. While a change request is
	* in-flight, will return the current (i.e. old, unmodified) value.
	*
	* @param domain_id Domain ID to query
	* @return Current performance level of the specified domain
	*/
	PerfLevel perfLevel(DomainID domain_id) const {
	assert(isEnabled());
	return findDomain(domain_id)->perfLevel();
	}

	/**
	* Read the clock period of the specified domain at the specified
	* performance level.
	* @param domain_id Domain ID to query
	* @param perf_level Performance level of interest
	* @return Clock period in ticks for the requested performance level of
	* the respective domain
	*/
	Tick clkPeriodAtPerfLevel(DomainID domain_id, PerfLevel perf_level) const
	{
	SrcClockDomain *d = findDomain(domain_id);
	assert(d);
	PerfLevel n = d->numPerfLevels();
	if (perf_level < n)
	return d->clkPeriodAtPerfLevel(perf_level);

	warn("DVFSHandler %s reads illegal frequency level %u from "\
	"SrcClockDomain %s. Returning 0\n", name(), perf_level, d->name());
	return Tick(0);
	}

	/**
	* Read the voltage of the specified domain at the specified
	* performance level.
	* @param domain_id Domain ID to query
	* @param perf_level Performance level of interest
	* @return Voltage for the requested performance level of the respective
	* domain
	*/
	double voltageAtPerfLevel(DomainID domain_id, PerfLevel perf_level) const;

	/**
	* Get the total number of available performance levels.
	*
	* @param domain_id Domain ID to query
	* @return Number of performance levels that where configured for the
	* respective domain
	*/
	PerfLevel numPerfLevels(PerfLevel domain_id) const
	{
	return findDomain(domain_id)->numPerfLevels();
	}

	/**
	* Check enable status of the DVFS handler, when the handler is disabled, no
	* request should be sent to the handler.
	* @return True, if the handler is enabled
	*/
	bool isEnabled() const { return enableHandler; }

	void serialize(CheckpointOut &cp) const override;
	void unserialize(CheckpointIn &cp) override;

	private:
	typedef std::map<DomainID, SrcClockDomain*> Domains;
	Domains domains;

	/**
	* List of IDs avaiable in the domain list
	*/
	std::vector<DomainID> domainIDList;

	/**
	* Clock domain of the system the handler is instantiated.
	*/
	SrcClockDomain* sysClkDomain;

	/**
	* Search for a domain based on the domain ID.
	*
	* @param domain_id Domain ID to search for
	* @return Pointer to the source clock domain with matching ID.
	*/
	SrcClockDomain *findDomain(DomainID domain_id) const {
	auto it = domains.find(domain_id);
	panic_if(it == domains.end(),
	"DVFS: Could not find a domain for ID %d.\n",domain_id );
	return domains.find(domain_id)->second;
	}

	/**
	* Disabling the DVFS handler ensures that all the DVFS migration requests
	* are ignored. Domains remain at their default frequency and voltage.
	*/
	bool enableHandler;


	/**
	* This corresponds to the maximum transition latency associated with the
	* hardware transitioning from a particular performance level to the other
	*/
	const Tick _transLatency;



	/**
	* Update performance level event, encapsulates all the required information
	* for a future call to change a domain's performance level.
	*/
	struct UpdateEvent : public Event
	{
	UpdateEvent() : Event(DVFS_Update_Pri), domainIDToSet(0),
	perfLevelToSet(0) {}

	/**
	* Static pointer to the single DVFS hander for all the update events
	*/
	static DVFSHandler *dvfsHandler;

	/**
	* ID of the domain that will be changed by the in-flight event
	*/
	DomainID domainIDToSet;

	/**
	* Target performance level of the in-flight event
	*/
	PerfLevel perfLevelToSet;

	/**
	* Updates the performance level by modifying the clock and the voltage
	* of the associated clocked objects. Gets information from
	* domainIDToSet and perfLevelToSet for easier calling through an
	* event.
	*/
	void updatePerfLevel();

	void process() { updatePerfLevel(); }
	};

	typedef std::map<DomainID, UpdateEvent> UpdatePerfLevelEvents;
	/**
	* Map from domain IDs -> perf level update events, records in-flight change
	* requests per domain ID.
	*/
	UpdatePerfLevelEvents updatePerfLevelEvents;
	};

	} // namespace gem5

	#endif // __SIM_DVFS_HANDLER_HH__