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Diffstat (limited to 'src/mem/qos/q_policy.cc')
| -rw-r--r-- | src/mem/qos/q_policy.cc | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/src/mem/qos/q_policy.cc b/src/mem/qos/q_policy.cc new file mode 100644 index 000000000..88ce95d0a --- /dev/null +++ b/src/mem/qos/q_policy.cc @@ -0,0 +1,147 @@ +/* + * 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 |