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/*
* Copyright (c) 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.
*
* 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.
*
* Author: Matteo Andreozzi
*/
#include "mem/qos/q_policy.hh"
#include <unordered_map>
#include <utility>
#include "debug/QOS.hh"
#include "enums/QoSQPolicy.hh"
#include "mem/qos/mem_ctrl.hh"
namespace QoS {
QueuePolicy*
QueuePolicy::create(const QoSMemCtrlParams* p)
{
switch (p->qos_q_policy) {
case Enums::QoSQPolicy::fifo:
return new FifoQueuePolicy(p);
case Enums::QoSQPolicy::lrg:
return new LrgQueuePolicy(p);
case Enums::QoSQPolicy::lifo:
default:
return new LifoQueuePolicy(p);
}
}
QueuePolicy::PacketQueue::iterator
LrgQueuePolicy::selectPacket(PacketQueue* q)
{
QueuePolicy::PacketQueue::iterator ret = q->end();
// Tracks one packet per master in the queue
std::unordered_map<MasterID, QueuePolicy::PacketQueue::iterator> track;
// Cycle queue only once
for (auto pkt_it = q->begin(); pkt_it != q->end(); ++pkt_it) {
const auto& pkt = *pkt_it;
panic_if(!pkt->req,
"QoSQPolicy::lrg detected packet without request");
// Get Request MasterID
MasterID m_id = pkt->req->masterId();
DPRINTF(QOS, "QoSQPolicy::lrg checking packet "
"from queue with id %d\n", m_id);
// Check if this is a known master.
panic_if(memCtrl->hasMaster(m_id),
"%s: Unrecognized Master\n", __func__);
panic_if(toServe.size() > 0,
"%s: toServe list is empty\n", __func__);
if (toServe.front() == m_id) {
DPRINTF(QOS, "QoSQPolicy::lrg matched to served "
"master id %d\n", m_id);
// This packet matches the MasterID to be served next
// move toServe front to back
toServe.push_back(m_id);
toServe.pop_front();
return pkt_it;
}
// The master generating the packet is not first in the toServe list
// (Doesn't have the highest priority among masters)
// Check if this is the first packet seen with its master ID
// and remember it. Then keep looping over the remaining packets
// in the queue.
if (track.find(m_id) == track.end()) {
track[m_id] = pkt_it;
DPRINTF(QOS, "QoSQPolicy::lrg tracking a packet for "
"master id %d\n", m_id);
}
}
// If here, the current master to be serviced doesn't have a pending
// packet in the queue: look for the next master in the list.
for (const auto& masterId : toServe) {
DPRINTF(QOS, "QoSQPolicy::lrg evaluating alternative "
"master id %d\n", masterId);
if (track.find(masterId) != track.end()) {
ret = track[masterId];
DPRINTF(QOS, "QoSQPolicy::lrg master id "
"%d selected for service\n", masterId);
return ret;
}
}
DPRINTF(QOS, "QoSQPolicy::lrg no packet was serviced\n");
// Ret will be : packet to serve if any found or queue begin
// (end if queue is empty)
return ret;
}
void
LrgQueuePolicy::enqueuePacket(PacketPtr pkt)
{
MasterID m_id = pkt->masterId();
if (!memCtrl->hasMaster(m_id)) {
toServe.push_back(m_id);
}
};
} // namespace QoS
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