c086c20bd2
Instead of conservatively enforcing order for all packets, which may negatively impact the simulated-system performance, this patch updates the packet queue such that it only applies the restriction if there are already packets with the same address in the queue. The basic need for the order enforcement is due to coherency interactions where requests/responses to the same cache line must not over-take each other. We rely on the fact that any packet that needs order enforcement will have a block-aligned address. Thus, there is no need for the queue to know about the cacheline size.
302 lines
9.7 KiB
C++
302 lines
9.7 KiB
C++
/*
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* Copyright (c) 2012,2015 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) 2006 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: Ali Saidi
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* Andreas Hansson
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*/
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#ifndef __MEM_PACKET_QUEUE_HH__
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#define __MEM_PACKET_QUEUE_HH__
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/**
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* @file
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* Declaration of a simple PacketQueue that is associated with
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* a port on which it attempts to send packets according to the time
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* stamp given to them at insertion. The packet queue is responsible
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* for the flow control of the port.
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*/
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#include <list>
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#include "mem/port.hh"
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#include "sim/drain.hh"
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#include "sim/eventq_impl.hh"
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/**
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* A packet queue is a class that holds deferred packets and later
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* sends them using the associated slave port or master port.
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*/
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class PacketQueue : public Drainable
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{
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private:
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/** A deferred packet, buffered to transmit later. */
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class DeferredPacket {
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public:
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Tick tick; ///< The tick when the packet is ready to transmit
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PacketPtr pkt; ///< Pointer to the packet to transmit
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DeferredPacket(Tick t, PacketPtr p)
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: tick(t), pkt(p)
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{}
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};
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typedef std::list<DeferredPacket> DeferredPacketList;
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/** A list of outgoing packets. */
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DeferredPacketList transmitList;
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/** The manager which is used for the event queue */
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EventManager& em;
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/** Used to schedule sending of deferred packets. */
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void processSendEvent();
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/** Event used to call processSendEvent. */
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EventWrapper<PacketQueue, &PacketQueue::processSendEvent> sendEvent;
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/*
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* Optionally disable the sanity check
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* on the size of the transmitList. The
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* sanity check will be enabled by default.
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*/
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bool _disableSanityCheck;
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protected:
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/** Label to use for print request packets label stack. */
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const std::string label;
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/** Remember whether we're awaiting a retry. */
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bool waitingOnRetry;
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/** Check whether we have a packet ready to go on the transmit list. */
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bool deferredPacketReady() const
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{ return !transmitList.empty() && transmitList.front().tick <= curTick(); }
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/**
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* Attempt to send a packet. Note that a subclass of the
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* PacketQueue can override this method and thus change the
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* behaviour (as done by the cache for the request queue). The
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* default implementation sends the head of the transmit list. The
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* caller must guarantee that the list is non-empty and that the
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* head packet is scheduled for curTick() (or earlier).
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*/
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virtual void sendDeferredPacket();
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/**
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* Send a packet using the appropriate method for the specific
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* subclass (reuest, response or snoop response).
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*/
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virtual bool sendTiming(PacketPtr pkt) = 0;
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/**
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* Create a packet queue, linked to an event manager, and a label
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* that will be used for functional print request packets.
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*
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* @param _em Event manager used for scheduling this queue
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* @param _label Label to push on the label stack for print request packets
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* @param disable_sanity_check Flag used to disable the sanity check
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* on the size of the transmitList. The check is enabled by default.
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*/
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PacketQueue(EventManager& _em, const std::string& _label,
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bool disable_sanity_check = false);
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/**
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* Virtual desctructor since the class may be used as a base class.
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*/
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virtual ~PacketQueue();
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public:
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/**
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* Provide a name to simplify debugging.
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*
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* @return A complete name, appended to module and port
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*/
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virtual const std::string name() const = 0;
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/**
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* Get the size of the queue.
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*/
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size_t size() const { return transmitList.size(); }
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/**
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* Get the next packet ready time.
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*/
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Tick deferredPacketReadyTime() const
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{ return transmitList.empty() ? MaxTick : transmitList.front().tick; }
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/**
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* Check if a packets address exists in the queue.
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*/
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bool hasAddr(Addr addr) const;
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/** Check the list of buffered packets against the supplied
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* functional request. */
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bool checkFunctional(PacketPtr pkt);
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/**
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* Schedule a send event if we are not already waiting for a
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* retry. If the requested time is before an already scheduled
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* send event, the event will be rescheduled. If MaxTick is
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* passed, no event is scheduled. Instead, if we are idle and
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* asked to drain then check and signal drained.
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*
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* @param when time to schedule an event
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*/
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void schedSendEvent(Tick when);
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/**
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* Add a packet to the transmit list, and schedule a send event.
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*
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* @param pkt Packet to send
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* @param when Absolute time (in ticks) to send packet
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* @param force_order Force insertion order for packets with same address
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*/
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void schedSendTiming(PacketPtr pkt, Tick when, bool force_order = false);
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/**
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* Retry sending a packet from the queue. Note that this is not
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* necessarily the same packet if something has been added with an
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* earlier time stamp.
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*/
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void retry();
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/**
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* This allows a user to explicitly disable the sanity check
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* on the size of the transmitList, which is enabled by default.
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* Users must use this function to explicitly disable the sanity
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* check.
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*/
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void disableSanityCheck() { _disableSanityCheck = true; }
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DrainState drain() override;
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};
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class ReqPacketQueue : public PacketQueue
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{
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protected:
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MasterPort& masterPort;
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public:
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/**
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* Create a request packet queue, linked to an event manager, a
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* master port, and a label that will be used for functional print
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* request packets.
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*
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* @param _em Event manager used for scheduling this queue
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* @param _masterPort Master port used to send the packets
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* @param _label Label to push on the label stack for print request packets
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*/
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ReqPacketQueue(EventManager& _em, MasterPort& _masterPort,
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const std::string _label = "ReqPacketQueue");
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virtual ~ReqPacketQueue() { }
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const std::string name() const
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{ return masterPort.name() + "-" + label; }
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bool sendTiming(PacketPtr pkt);
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};
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class SnoopRespPacketQueue : public PacketQueue
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{
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protected:
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MasterPort& masterPort;
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public:
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/**
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* Create a snoop response packet queue, linked to an event
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* manager, a master port, and a label that will be used for
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* functional print request packets.
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*
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* @param _em Event manager used for scheduling this queue
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* @param _masterPort Master port used to send the packets
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* @param _label Label to push on the label stack for print request packets
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*/
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SnoopRespPacketQueue(EventManager& _em, MasterPort& _masterPort,
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const std::string _label = "SnoopRespPacketQueue");
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virtual ~SnoopRespPacketQueue() { }
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const std::string name() const
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{ return masterPort.name() + "-" + label; }
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bool sendTiming(PacketPtr pkt);
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};
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class RespPacketQueue : public PacketQueue
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{
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protected:
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SlavePort& slavePort;
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public:
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/**
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* Create a response packet queue, linked to an event manager, a
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* slave port, and a label that will be used for functional print
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* request packets.
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*
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* @param _em Event manager used for scheduling this queue
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* @param _slavePort Slave port used to send the packets
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* @param _label Label to push on the label stack for print request packets
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*/
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RespPacketQueue(EventManager& _em, SlavePort& _slavePort,
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const std::string _label = "RespPacketQueue");
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virtual ~RespPacketQueue() { }
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const std::string name() const
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{ return slavePort.name() + "-" + label; }
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bool sendTiming(PacketPtr pkt);
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};
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#endif // __MEM_PACKET_QUEUE_HH__
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