ed38e3432c
The drain() call currently passes around a DrainManager pointer, which is now completely pointless since there is only ever one global DrainManager in the system. It also contains vestiges from the time when SimObjects had to keep track of their child objects that needed draining. This changeset moves all of the DrainState handling to the Drainable base class and changes the drain() and drainResume() calls to reflect this. Particularly, the drain() call has been updated to take no parameters (the DrainManager argument isn't needed) and return a DrainState instead of an unsigned integer (there is no point returning anything other than 0 or 1 any more). Drainable objects should return either DrainState::Draining (equivalent to returning 1 in the old system) if they need more time to drain or DrainState::Drained (equivalent to returning 0 in the old system) if they are already in a consistent state. Returning DrainState::Running is considered an error. Drain done signalling is now done through the signalDrainDone() method in the Drainable class instead of using the DrainManager directly. The new call checks if the state of the object is DrainState::Draining before notifying the drain manager. This means that it is safe to call signalDrainDone() without first checking if the simulator has requested draining. The intention here is to reduce the code needed to implement draining in simple objects.
262 lines
8.7 KiB
C++
262 lines
8.7 KiB
C++
/*
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* Copyright (c) 2012-2013, 2015 ARM Limited
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* All rights reserved.
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*
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* The license below extends only to copyright in the software and shall
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* not be construed as granting a license to any other intellectual
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* property including but not limited to intellectual property relating
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* to a hardware implementation of the functionality of the software
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* licensed hereunder. You may use the software subject to the license
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* terms below provided that you ensure that this notice is replicated
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* unmodified and in its entirety in all distributions of the software,
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* modified or unmodified, in source code or in binary form.
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*
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* Copyright (c) 2003-2005 The Regents of The University of Michigan
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met: redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer;
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* redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution;
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* neither the name of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* Authors: Erik Hallnor
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* Andreas Sandberg
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*/
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/** @file
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* Declaration of a structure to manage MSHRs.
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*/
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#ifndef __MEM_CACHE_MSHR_QUEUE_HH__
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#define __MEM_CACHE_MSHR_QUEUE_HH__
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#include <vector>
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#include "mem/cache/mshr.hh"
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#include "mem/packet.hh"
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#include "sim/drain.hh"
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/**
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* A Class for maintaining a list of pending and allocated memory requests.
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*/
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class MSHRQueue : public Drainable
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{
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private:
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/** Local label (for functional print requests) */
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const std::string label;
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// Parameters
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/**
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* The total number of entries in this queue. This number is set as the
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* number of entries requested plus (numReserve - 1). This allows for
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* the same number of effective entries while still maintaining the reserve.
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*/
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const int numEntries;
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/**
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* The number of entries to hold in reserve. This is needed because copy
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* operations can allocate upto 4 entries at one time.
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*/
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const int numReserve;
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/**
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* The number of entries to reserve for future demand accesses.
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* Prevent prefetcher from taking all mshr entries
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*/
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const int demandReserve;
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/** MSHR storage. */
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std::vector<MSHR> registers;
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/** Holds pointers to all allocated entries. */
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MSHR::List allocatedList;
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/** Holds pointers to entries that haven't been sent to the bus. */
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MSHR::List readyList;
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/** Holds non allocated entries. */
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MSHR::List freeList;
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MSHR::Iterator addToReadyList(MSHR *mshr);
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public:
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/** The number of allocated entries. */
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int allocated;
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/** The number of entries that have been forwarded to the bus. */
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int inServiceEntries;
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/** The index of this queue within the cache (MSHR queue vs. write
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* buffer). */
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const int index;
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/**
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* Create a queue with a given number of entries.
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* @param num_entrys The number of entries in this queue.
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* @param reserve The minimum number of entries needed to satisfy
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* any access.
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* @param demand_reserve The minimum number of entries needed to satisfy
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* demand accesses.
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*/
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MSHRQueue(const std::string &_label, int num_entries, int reserve,
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int demand_reserve, int index);
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/**
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* Find the first MSHR that matches the provided address.
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* @param blk_addr The block address to find.
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* @param is_secure True if the target memory space is secure.
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* @return Pointer to the matching MSHR, null if not found.
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*/
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MSHR *findMatch(Addr blk_addr, bool is_secure) const;
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/**
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* Find and return all the matching entries in the provided vector.
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* @param blk_addr The block address to find.
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* @param is_secure True if the target memory space is secure.
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* @param matches The vector to return pointers to the matching entries.
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* @return True if any matches are found, false otherwise.
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*/
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bool findMatches(Addr blk_addr, bool is_secure,
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std::vector<MSHR*>& matches) const;
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/**
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* Find any pending requests that overlap the given request.
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* @param blk_addr Block address.
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* @param is_secure True if the target memory space is secure.
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* @return A pointer to the earliest matching MSHR.
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*/
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MSHR *findPending(Addr blk_addr, bool is_secure) const;
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bool checkFunctional(PacketPtr pkt, Addr blk_addr);
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/**
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* Allocates a new MSHR for the request and size. This places the request
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* as the first target in the MSHR.
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*
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* @param blk_addr The address of the block.
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* @param blk_size The number of bytes to request.
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* @param pkt The original miss.
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* @param when_ready When should the MSHR be ready to act upon.
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* @param order The logical order of this MSHR
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*
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* @return The a pointer to the MSHR allocated.
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*
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* @pre There are free entries.
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*/
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MSHR *allocate(Addr blk_addr, unsigned blk_size, PacketPtr pkt,
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Tick when_ready, Counter order);
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/**
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* Removes the given MSHR from the queue. This places the MSHR on the
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* free list.
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* @param mshr
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*/
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void deallocate(MSHR *mshr);
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/**
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* Remove a MSHR from the queue. Returns an iterator into the
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* allocatedList for faster squash implementation.
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* @param mshr The MSHR to remove.
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* @return An iterator to the next entry in the allocatedList.
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*/
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MSHR::Iterator deallocateOne(MSHR *mshr);
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/**
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* Moves the MSHR to the front of the pending list if it is not
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* in service.
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* @param mshr The entry to move.
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*/
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void moveToFront(MSHR *mshr);
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/**
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* Mark the given MSHR as in service. This removes the MSHR from the
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* readyList or deallocates the MSHR if it does not expect a response.
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*
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* @param mshr The MSHR to mark in service.
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* @param pending_dirty_resp Whether we expect a dirty response
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* from another cache
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*/
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void markInService(MSHR *mshr, bool pending_dirty_resp);
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/**
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* Mark an in service entry as pending, used to resend a request.
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* @param mshr The MSHR to resend.
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*/
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void markPending(MSHR *mshr);
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/**
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* Squash outstanding requests with the given thread number. If a request
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* is in service, just squashes the targets.
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* @param threadNum The thread to squash.
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*/
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void squash(int threadNum);
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/**
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* Deallocate top target, possibly freeing the MSHR
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* @return if MSHR queue is no longer full
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*/
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bool forceDeallocateTarget(MSHR *mshr);
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/**
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* Returns true if the pending list is not empty.
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* @return True if there are outstanding requests.
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*/
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bool havePending() const
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{
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return !readyList.empty();
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}
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/**
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* Returns true if there are no free entries.
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* @return True if this queue is full.
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*/
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bool isFull() const
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{
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return (allocated > numEntries - numReserve);
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}
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/**
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* Returns true if sufficient mshrs for prefetch.
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* @return True if sufficient mshrs for prefetch.
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*/
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bool canPrefetch() const
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{
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return (allocated < numEntries - (numReserve + demandReserve));
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}
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/**
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* Returns the MSHR at the head of the readyList.
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* @return The next request to service.
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*/
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MSHR *getNextMSHR() const
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{
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if (readyList.empty() || readyList.front()->readyTime > curTick()) {
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return NULL;
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}
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return readyList.front();
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}
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Tick nextMSHRReadyTime() const
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{
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return readyList.empty() ? MaxTick : readyList.front()->readyTime;
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}
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DrainState drain() M5_ATTR_OVERRIDE;
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};
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#endif //__MEM_CACHE_MSHR_QUEUE_HH__
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