From 041ea8107e4250a9c120a6fde11f3dc415c2fe6a Mon Sep 17 00:00:00 2001 From: Andreas Hansson Date: Thu, 17 Mar 2016 09:51:18 -0400 Subject: mem: Create a separate class for the cache write buffer This patch breaks out the cache write buffer into a separate class, without affecting any stats. The goal of the patch is to avoid encumbering the much-simpler write queue with the complex MSHR handling. In a follow on patch this simplification allows us to implement write combining. The WriteQueue gets its own class, but shares a common ancestor, the generic Queue, with the MSHRQueue. --- src/mem/cache/write_queue_entry.hh | 194 +++++++++++++++++++++++++++++++++++++ 1 file changed, 194 insertions(+) create mode 100644 src/mem/cache/write_queue_entry.hh (limited to 'src/mem/cache/write_queue_entry.hh') diff --git a/src/mem/cache/write_queue_entry.hh b/src/mem/cache/write_queue_entry.hh new file mode 100644 index 000000000..7e3422431 --- /dev/null +++ b/src/mem/cache/write_queue_entry.hh @@ -0,0 +1,194 @@ +/* + * Copyright (c) 2012-2013, 2015-2016 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) 2002-2005 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 Hansson + */ + +/** + * @file + * Write queue entry + */ + +#ifndef __MEM_CACHE_WRITE_QUEUE_ENTRY_HH__ +#define __MEM_CACHE_WRITE_QUEUE_ENTRY_HH__ + +#include + +#include "base/printable.hh" +#include "mem/cache/queue_entry.hh" + +class Cache; + +/** + * Write queue entry + */ +class WriteQueueEntry : public QueueEntry, public Printable +{ + + /** + * Consider the queues friends to avoid making everything public. + */ + template + friend class Queue; + friend class WriteQueue; + + public: + + class Target { + public: + + const Tick recvTime; //!< Time when request was received (for stats) + const Tick readyTime; //!< Time when request is ready to be serviced + const Counter order; //!< Global order (for memory consistency mgmt) + const PacketPtr pkt; //!< Pending request packet. + + Target(PacketPtr _pkt, Tick _readyTime, Counter _order) + : recvTime(curTick()), readyTime(_readyTime), order(_order), + pkt(_pkt) + {} + }; + + class TargetList : public std::list { + + public: + + TargetList() {} + void add(PacketPtr pkt, Tick readyTime, Counter order); + bool checkFunctional(PacketPtr pkt); + void print(std::ostream &os, int verbosity, + const std::string &prefix) const; + }; + + /** A list of write queue entriess. */ + typedef std::list List; + /** WriteQueueEntry list iterator. */ + typedef List::iterator Iterator; + + bool sendPacket(Cache &cache); + + private: + + /** + * Pointer to this entry on the ready list. + * @sa MissQueue, WriteQueue::readyList + */ + Iterator readyIter; + + /** + * Pointer to this entry on the allocated list. + * @sa MissQueue, WriteQueue::allocatedList + */ + Iterator allocIter; + + /** List of all requests that match the address */ + TargetList targets; + + public: + + /** A simple constructor. */ + WriteQueueEntry() {} + + /** + * Allocate a miss to this entry. + * @param blk_addr The address of the block. + * @param blk_size The number of bytes to request. + * @param pkt The original write. + * @param when_ready When should the write be sent out. + * @param _order The logical order of this write. + */ + void allocate(Addr blk_addr, unsigned blk_size, PacketPtr pkt, + Tick when_ready, Counter _order); + + bool markInService(); + + /** + * Mark this entry as free. + */ + void deallocate(); + + /** + * Returns the current number of allocated targets. + * @return The current number of allocated targets. + */ + int getNumTargets() const + { return targets.size(); } + + /** + * Returns true if there are targets left. + * @return true if there are targets + */ + bool hasTargets() const { return !targets.empty(); } + + /** + * Returns a reference to the first target. + * @return A pointer to the first target. + */ + Target *getTarget() + { + assert(hasTargets()); + return &targets.front(); + } + + /** + * Pop first target. + */ + void popTarget() + { + targets.pop_front(); + } + + bool checkFunctional(PacketPtr pkt); + + /** + * Prints the contents of this MSHR for debugging. + */ + void print(std::ostream &os, + int verbosity = 0, + const std::string &prefix = "") const; + /** + * A no-args wrapper of print(std::ostream...) meant to be + * invoked from DPRINTFs avoiding string overheads in fast mode + * + * @return string with mshr fields + */ + std::string print() const; +}; + +#endif // __MEM_CACHE_WRITE_QUEUE_ENTRY_HH__ -- cgit v1.2.3