src/mem/cache/queue.hh - public/gem5 - Git at Google

 /*
  * Copyright (c) 2012-2013, 2015-2016, 2018 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.
  */

 /** @file
  * Declaration of a high-level queue structure
  */

 #ifndef __MEM_CACHE_QUEUE_HH__
 #define __MEM_CACHE_QUEUE_HH__

 #include <cassert>
 #include <string>
 #include <type_traits>

 #include "base/logging.hh"
 #include "base/trace.hh"
 #include "base/types.hh"
 #include "debug/Drain.hh"
 #include "mem/cache/queue_entry.hh"
 #include "mem/packet.hh"
 #include "sim/core.hh"
 #include "sim/drain.hh"

 /**
  * A high-level queue interface, to be used by both the MSHR queue and
  * the write buffer.
  */
 template<class Entry>
 class Queue : public Drainable
 {
     static_assert(std::is_base_of<QueueEntry, Entry>::value,
         "Entry must be derived from QueueEntry");

   protected:
     /** Local label (for functional print requests) */
     const std::string label;

     /**
      * The total number of entries in this queue. This number is set
      * as the number of entries requested plus any reserve. This
      * allows for the same number of effective entries while still
      * maintaining an overflow reserve.
      */
     const int numEntries;

     /**
      * The number of entries to hold as a temporary overflow
      * space. This is used to allow temporary overflow of the number
      * of entries as we only check the full condition under certain
      * conditions.
      */
     const int numReserve;

     /**  Actual storage. */
     std::vector<Entry> entries;
     /** Holds pointers to all allocated entries. */
     typename Entry::List allocatedList;
     /** Holds pointers to entries that haven't been sent downstream. */
     typename Entry::List readyList;
     /** Holds non allocated entries. */
     typename Entry::List freeList;

     typename Entry::Iterator addToReadyList(Entry* entry)
     {
         if (readyList.empty() ||
             readyList.back()->readyTime <= entry->readyTime) {
             return readyList.insert(readyList.end(), entry);
         }

         for (auto i = readyList.begin(); i != readyList.end(); ++i) {
             if ((*i)->readyTime > entry->readyTime) {
                 return readyList.insert(i, entry);
             }
         }
         panic("Failed to add to ready list.");
     }

     /** The number of entries that are in service. */
     int _numInService;

     /** The number of currently allocated entries. */
     int allocated;

   public:

     /**
      * Create a queue with a given number of entries.
      *
      * @param num_entries The number of entries in this queue.
      * @param reserve The extra overflow entries needed.
      */
     Queue(const std::string &_label, int num_entries, int reserve) :
         label(_label), numEntries(num_entries + reserve),
         numReserve(reserve), entries(numEntries), _numInService(0),
         allocated(0)
     {
         for (int i = 0; i < numEntries; ++i) {
             freeList.push_back(&entries[i]);
         }
     }

     bool isEmpty() const
     {
         return allocated == 0;
     }

     bool isFull() const
     {
         return (allocated >= numEntries - numReserve);
     }

     int numInService() const
     {
         return _numInService;
     }

     /**
      * Find the first entry that matches the provided address.
      *
      * @param blk_addr The block address to find.
      * @param is_secure True if the target memory space is secure.
      * @param ignore_uncacheable Should uncacheables be ignored or not
      * @return Pointer to the matching WriteQueueEntry, null if not found.
      */
     Entry* findMatch(Addr blk_addr, bool is_secure,
                      bool ignore_uncacheable = true) const
     {
         for (const auto& entry : allocatedList) {
             // we ignore any entries allocated for uncacheable
             // accesses and simply ignore them when matching, in the
             // cache we never check for matches when adding new
             // uncacheable entries, and we do not want normal
             // cacheable accesses being added to an WriteQueueEntry
             // serving an uncacheable access
             if (!(ignore_uncacheable && entry->isUncacheable()) &&
                 entry->matchBlockAddr(blk_addr, is_secure)) {
                 return entry;
             }
         }
         return nullptr;
     }

     bool trySatisfyFunctional(PacketPtr pkt)
     {
         pkt->pushLabel(label);
         for (const auto& entry : allocatedList) {
             if (entry->matchBlockAddr(pkt) &&
                 entry->trySatisfyFunctional(pkt)) {
                 pkt->popLabel();
                 return true;
             }
         }
         pkt->popLabel();
         return false;
     }

     /**
      * Find any pending requests that overlap the given request of a
      * different queue.
      *
      * @param entry The entry to be compared against.
      * @return A pointer to the earliest matching entry.
      */
     Entry* findPending(const QueueEntry* entry) const
     {
         for (const auto& ready_entry : readyList) {
             if (ready_entry->conflictAddr(entry)) {
                 return ready_entry;
             }
         }
         return nullptr;
     }

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

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

     /**
      * Removes the given entry from the queue. This places the entry
      * on the free list.
      *
      * @param entry
      */
     void deallocate(Entry *entry)
     {
         allocatedList.erase(entry->allocIter);
         freeList.push_front(entry);
         allocated--;
         if (entry->inService) {
             _numInService--;
         } else {
             readyList.erase(entry->readyIter);
         }
         entry->deallocate();
         if (drainState() == DrainState::Draining && allocated == 0) {
             // Notify the drain manager that we have completed
             // draining if there are no other outstanding requests in
             // this queue.
             DPRINTF(Drain, "Queue now empty, signalling drained\n");
             signalDrainDone();
         }
     }

     DrainState drain() override
     {
         return allocated == 0 ? DrainState::Drained : DrainState::Draining;
     }
 };

 #endif //__MEM_CACHE_QUEUE_HH__
	/*
	* Copyright (c) 2012-2013, 2015-2016, 2018 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.
	*/

	/** @file
	* Declaration of a high-level queue structure
	*/

	#ifndef __MEM_CACHE_QUEUE_HH__
	#define __MEM_CACHE_QUEUE_HH__

	#include <cassert>
	#include <string>
	#include <type_traits>

	#include "base/logging.hh"
	#include "base/trace.hh"
	#include "base/types.hh"
	#include "debug/Drain.hh"
	#include "mem/cache/queue_entry.hh"
	#include "mem/packet.hh"
	#include "sim/core.hh"
	#include "sim/drain.hh"

	/**
	* A high-level queue interface, to be used by both the MSHR queue and
	* the write buffer.
	*/
	template<class Entry>
	class Queue : public Drainable
	{
	static_assert(std::is_base_of<QueueEntry, Entry>::value,
	"Entry must be derived from QueueEntry");

	protected:
	/** Local label (for functional print requests) */
	const std::string label;

	/**
	* The total number of entries in this queue. This number is set
	* as the number of entries requested plus any reserve. This
	* allows for the same number of effective entries while still
	* maintaining an overflow reserve.
	*/
	const int numEntries;

	/**
	* The number of entries to hold as a temporary overflow
	* space. This is used to allow temporary overflow of the number
	* of entries as we only check the full condition under certain
	* conditions.
	*/
	const int numReserve;

	/** Actual storage. */
	std::vector<Entry> entries;
	/** Holds pointers to all allocated entries. */
	typename Entry::List allocatedList;
	/** Holds pointers to entries that haven't been sent downstream. */
	typename Entry::List readyList;
	/** Holds non allocated entries. */
	typename Entry::List freeList;

	typename Entry::Iterator addToReadyList(Entry* entry)
	{
	if (readyList.empty() \|\|
	readyList.back()->readyTime <= entry->readyTime) {
	return readyList.insert(readyList.end(), entry);
	}

	for (auto i = readyList.begin(); i != readyList.end(); ++i) {
	if ((*i)->readyTime > entry->readyTime) {
	return readyList.insert(i, entry);
	}
	}
	panic("Failed to add to ready list.");
	}

	/** The number of entries that are in service. */
	int _numInService;

	/** The number of currently allocated entries. */
	int allocated;

	public:

	/**
	* Create a queue with a given number of entries.
	*
	* @param num_entries The number of entries in this queue.
	* @param reserve The extra overflow entries needed.
	*/
	Queue(const std::string &_label, int num_entries, int reserve) :
	label(_label), numEntries(num_entries + reserve),
	numReserve(reserve), entries(numEntries), _numInService(0),
	allocated(0)
	{
	for (int i = 0; i < numEntries; ++i) {
	freeList.push_back(&entries[i]);
	}
	}

	bool isEmpty() const
	{
	return allocated == 0;
	}

	bool isFull() const
	{
	return (allocated >= numEntries - numReserve);
	}

	int numInService() const
	{
	return _numInService;
	}

	/**
	* Find the first entry that matches the provided address.
	*
	* @param blk_addr The block address to find.
	* @param is_secure True if the target memory space is secure.
	* @param ignore_uncacheable Should uncacheables be ignored or not
	* @return Pointer to the matching WriteQueueEntry, null if not found.
	*/
	Entry* findMatch(Addr blk_addr, bool is_secure,
	bool ignore_uncacheable = true) const
	{
	for (const auto& entry : allocatedList) {
	// we ignore any entries allocated for uncacheable
	// accesses and simply ignore them when matching, in the
	// cache we never check for matches when adding new
	// uncacheable entries, and we do not want normal
	// cacheable accesses being added to an WriteQueueEntry
	// serving an uncacheable access
	if (!(ignore_uncacheable && entry->isUncacheable()) &&
	entry->matchBlockAddr(blk_addr, is_secure)) {
	return entry;
	}
	}
	return nullptr;
	}

	bool trySatisfyFunctional(PacketPtr pkt)
	{
	pkt->pushLabel(label);
	for (const auto& entry : allocatedList) {
	if (entry->matchBlockAddr(pkt) &&
	entry->trySatisfyFunctional(pkt)) {
	pkt->popLabel();
	return true;
	}
	}
	pkt->popLabel();
	return false;
	}

	/**
	* Find any pending requests that overlap the given request of a
	* different queue.
	*
	* @param entry The entry to be compared against.
	* @return A pointer to the earliest matching entry.
	*/
	Entry* findPending(const QueueEntry* entry) const
	{
	for (const auto& ready_entry : readyList) {
	if (ready_entry->conflictAddr(entry)) {
	return ready_entry;
	}
	}
	return nullptr;
	}

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

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

	/**
	* Removes the given entry from the queue. This places the entry
	* on the free list.
	*
	* @param entry
	*/
	void deallocate(Entry *entry)
	{
	allocatedList.erase(entry->allocIter);
	freeList.push_front(entry);
	allocated--;
	if (entry->inService) {
	_numInService--;
	} else {
	readyList.erase(entry->readyIter);
	}
	entry->deallocate();
	if (drainState() == DrainState::Draining && allocated == 0) {
	// Notify the drain manager that we have completed
	// draining if there are no other outstanding requests in
	// this queue.
	DPRINTF(Drain, "Queue now empty, signalling drained\n");
	signalDrainDone();
	}
	}

	DrainState drain() override
	{
	return allocated == 0 ? DrainState::Drained : DrainState::Draining;
	}
	};

	#endif //__MEM_CACHE_QUEUE_HH__