src/mem/cache/mshr_queue.hh - arm/gem5 - Git at Google

 /*
  * Copyright (c) 2012-2013 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.
  *
  * Copyright (c) 2003-2005 The Regents of The University of Michigan
  * All rights reserved.
  *
  * 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.
  *
  * Authors: Erik Hallnor
  *          Andreas Sandberg
  */

 /** @file
  * Declaration of a structure to manage MSHRs.
  */

 #ifndef __MEM__CACHE__MISS__MSHR_QUEUE_HH__
 #define __MEM__CACHE__MISS__MSHR_QUEUE_HH__

 #include <vector>

 #include "mem/cache/mshr.hh"
 #include "mem/packet.hh"
 #include "sim/drain.hh"

 /**
  * A Class for maintaining a list of pending and allocated memory requests.
  */
 class MSHRQueue : public Drainable
 {
   private:
     /** Local label (for functional print requests) */
     const std::string label;

     // Parameters
     /**
      * The total number of entries in this queue. This number is set as the
      * number of entries requested plus (numReserve - 1). This allows for
      * the same number of effective entries while still maintaining the reserve.
      */
     const int numEntries;

     /**
      * The number of entries to hold in reserve. This is needed because copy
      * operations can allocate upto 4 entries at one time.
      */
     const int numReserve;

     /**  MSHR storage. */
     std::vector<MSHR> registers;
     /** Holds pointers to all allocated entries. */
     MSHR::List allocatedList;
     /** Holds pointers to entries that haven't been sent to the bus. */
     MSHR::List readyList;
     /** Holds non allocated entries. */
     MSHR::List freeList;

     /** Drain manager to inform of a completed drain */
     DrainManager *drainManager;

     MSHR::Iterator addToReadyList(MSHR *mshr);


   public:
     /** The number of allocated entries. */
     int allocated;
     /** The number of entries that have been forwarded to the bus. */
     int inServiceEntries;
     /** The index of this queue within the cache (MSHR queue vs. write
      * buffer). */
     const int index;

     /**
      * Create a queue with a given number of entries.
      * @param num_entrys The number of entries in this queue.
      * @param reserve The minimum number of entries needed to satisfy
      * any access.
      */
     MSHRQueue(const std::string &_label, int num_entries, int reserve,
               int index);

     /**
      * Find the first MSHR that matches the provided address.
      * @param addr The address to find.
      * @param is_secure True if the target memory space is secure.
      * @return Pointer to the matching MSHR, null if not found.
      */
     MSHR *findMatch(Addr addr, bool is_secure) const;

     /**
      * Find and return all the matching entries in the provided vector.
      * @param addr The address to find.
      * @param is_secure True if the target memory space is secure.
      * @param matches The vector to return pointers to the matching entries.
      * @return True if any matches are found, false otherwise.
      * @todo Typedef the vector??
      */
     bool findMatches(Addr addr, bool is_secure,
                      std::vector<MSHR*>& matches) const;

     /**
      * Find any pending requests that overlap the given request.
      * @param pkt The request to find.
      * @param is_secure True if the target memory space is secure.
      * @return A pointer to the earliest matching MSHR.
      */
     MSHR *findPending(Addr addr, int size, bool is_secure) const;

     bool checkFunctional(PacketPtr pkt, Addr blk_addr);

     /**
      * Allocates a new MSHR for the request and size. This places the request
      * as the first target in the MSHR.
      * @param pkt The request to handle.
      * @param size The number in bytes to fetch from memory.
      * @return The a pointer to the MSHR allocated.
      *
      * @pre There are free entries.
      */
     MSHR *allocate(Addr addr, int size, PacketPtr &pkt,
                    Tick when, Counter order);

     /**
      * Removes the given MSHR from the queue. This places the MSHR on the
      * free list.
      * @param mshr
      */
     void deallocate(MSHR *mshr);

     /**
      * Remove a MSHR from the queue. Returns an iterator into the
      * allocatedList for faster squash implementation.
      * @param mshr The MSHR to remove.
      * @return An iterator to the next entry in the allocatedList.
      */
     MSHR::Iterator deallocateOne(MSHR *mshr);

     /**
      * Moves the MSHR to the front of the pending list if it is not
      * in service.
      * @param mshr The entry to move.
      */
     void moveToFront(MSHR *mshr);

     /**
      * Mark the given MSHR as in service. This removes the MSHR from the
      * readyList. Deallocates the MSHR if it does not expect a response.
      * @param mshr The MSHR to mark in service.
      */
     void markInService(MSHR *mshr, PacketPtr pkt);

     /**
      * Mark an in service entry as pending, used to resend a request.
      * @param mshr The MSHR to resend.
      */
     void markPending(MSHR *mshr);

     /**
      * Squash outstanding requests with the given thread number. If a request
      * is in service, just squashes the targets.
      * @param threadNum The thread to squash.
      */
     void squash(int threadNum);

     /**
      * Deallocate top target, possibly freeing the MSHR
      * @return if MSHR queue is no longer full
      */
     bool forceDeallocateTarget(MSHR *mshr);

     /**
      * Returns true if the pending list is not empty.
      * @return True if there are outstanding requests.
      */
     bool havePending() const
     {
         return !readyList.empty();
     }

     /**
      * Returns true if there are no free entries.
      * @return True if this queue is full.
      */
     bool isFull() const
     {
         return (allocated > numEntries - numReserve);
     }

     /**
      * Returns the MSHR at the head of the readyList.
      * @return The next request to service.
      */
     MSHR *getNextMSHR() const
     {
         if (readyList.empty() || readyList.front()->readyTime > curTick()) {
             return NULL;
         }
         return readyList.front();
     }

     Tick nextMSHRReadyTime() const
     {
         return readyList.empty() ? MaxTick : readyList.front()->readyTime;
     }

     unsigned int drain(DrainManager *dm);
 };

 #endif //__MEM__CACHE__MISS__MSHR_QUEUE_HH__
	/*
	* Copyright (c) 2012-2013 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.
	*
	* Copyright (c) 2003-2005 The Regents of The University of Michigan
	* All rights reserved.
	*
	* 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.
	*
	* Authors: Erik Hallnor
	* Andreas Sandberg
	*/

	/** @file
	* Declaration of a structure to manage MSHRs.
	*/

	#ifndef __MEM__CACHE__MISS__MSHR_QUEUE_HH__
	#define __MEM__CACHE__MISS__MSHR_QUEUE_HH__

	#include <vector>

	#include "mem/cache/mshr.hh"
	#include "mem/packet.hh"
	#include "sim/drain.hh"

	/**
	* A Class for maintaining a list of pending and allocated memory requests.
	*/
	class MSHRQueue : public Drainable
	{
	private:
	/** Local label (for functional print requests) */
	const std::string label;

	// Parameters
	/**
	* The total number of entries in this queue. This number is set as the
	* number of entries requested plus (numReserve - 1). This allows for
	* the same number of effective entries while still maintaining the reserve.
	*/
	const int numEntries;

	/**
	* The number of entries to hold in reserve. This is needed because copy
	* operations can allocate upto 4 entries at one time.
	*/
	const int numReserve;

	/** MSHR storage. */
	std::vector<MSHR> registers;
	/** Holds pointers to all allocated entries. */
	MSHR::List allocatedList;
	/** Holds pointers to entries that haven't been sent to the bus. */
	MSHR::List readyList;
	/** Holds non allocated entries. */
	MSHR::List freeList;

	/** Drain manager to inform of a completed drain */
	DrainManager *drainManager;

	MSHR::Iterator addToReadyList(MSHR *mshr);


	public:
	/** The number of allocated entries. */
	int allocated;
	/** The number of entries that have been forwarded to the bus. */
	int inServiceEntries;
	/** The index of this queue within the cache (MSHR queue vs. write
	* buffer). */
	const int index;

	/**
	* Create a queue with a given number of entries.
	* @param num_entrys The number of entries in this queue.
	* @param reserve The minimum number of entries needed to satisfy
	* any access.
	*/
	MSHRQueue(const std::string &_label, int num_entries, int reserve,
	int index);

	/**
	* Find the first MSHR that matches the provided address.
	* @param addr The address to find.
	* @param is_secure True if the target memory space is secure.
	* @return Pointer to the matching MSHR, null if not found.
	*/
	MSHR *findMatch(Addr addr, bool is_secure) const;

	/**
	* Find and return all the matching entries in the provided vector.
	* @param addr The address to find.
	* @param is_secure True if the target memory space is secure.
	* @param matches The vector to return pointers to the matching entries.
	* @return True if any matches are found, false otherwise.
	* @todo Typedef the vector??
	*/
	bool findMatches(Addr addr, bool is_secure,
	std::vector<MSHR*>& matches) const;

	/**
	* Find any pending requests that overlap the given request.
	* @param pkt The request to find.
	* @param is_secure True if the target memory space is secure.
	* @return A pointer to the earliest matching MSHR.
	*/
	MSHR *findPending(Addr addr, int size, bool is_secure) const;

	bool checkFunctional(PacketPtr pkt, Addr blk_addr);

	/**
	* Allocates a new MSHR for the request and size. This places the request
	* as the first target in the MSHR.
	* @param pkt The request to handle.
	* @param size The number in bytes to fetch from memory.
	* @return The a pointer to the MSHR allocated.
	*
	* @pre There are free entries.
	*/
	MSHR *allocate(Addr addr, int size, PacketPtr &pkt,
	Tick when, Counter order);

	/**
	* Removes the given MSHR from the queue. This places the MSHR on the
	* free list.
	* @param mshr
	*/
	void deallocate(MSHR *mshr);

	/**
	* Remove a MSHR from the queue. Returns an iterator into the
	* allocatedList for faster squash implementation.
	* @param mshr The MSHR to remove.
	* @return An iterator to the next entry in the allocatedList.
	*/
	MSHR::Iterator deallocateOne(MSHR *mshr);

	/**
	* Moves the MSHR to the front of the pending list if it is not
	* in service.
	* @param mshr The entry to move.
	*/
	void moveToFront(MSHR *mshr);

	/**
	* Mark the given MSHR as in service. This removes the MSHR from the
	* readyList. Deallocates the MSHR if it does not expect a response.
	* @param mshr The MSHR to mark in service.
	*/
	void markInService(MSHR *mshr, PacketPtr pkt);

	/**
	* Mark an in service entry as pending, used to resend a request.
	* @param mshr The MSHR to resend.
	*/
	void markPending(MSHR *mshr);

	/**
	* Squash outstanding requests with the given thread number. If a request
	* is in service, just squashes the targets.
	* @param threadNum The thread to squash.
	*/
	void squash(int threadNum);

	/**
	* Deallocate top target, possibly freeing the MSHR
	* @return if MSHR queue is no longer full
	*/
	bool forceDeallocateTarget(MSHR *mshr);

	/**
	* Returns true if the pending list is not empty.
	* @return True if there are outstanding requests.
	*/
	bool havePending() const
	{
	return !readyList.empty();
	}

	/**
	* Returns true if there are no free entries.
	* @return True if this queue is full.
	*/
	bool isFull() const
	{
	return (allocated > numEntries - numReserve);
	}

	/**
	* Returns the MSHR at the head of the readyList.
	* @return The next request to service.
	*/
	MSHR *getNextMSHR() const
	{
	if (readyList.empty() \|\| readyList.front()->readyTime > curTick()) {
	return NULL;
	}
	return readyList.front();
	}

	Tick nextMSHRReadyTime() const
	{
	return readyList.empty() ? MaxTick : readyList.front()->readyTime;
	}

	unsigned int drain(DrainManager *dm);
	};

	#endif //__MEM__CACHE__MISS__MSHR_QUEUE_HH__