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/*
* Copyright (c) 2018 ARM Limited
* All rights reserved
*
* The license below extends only to copyright in the software and shall
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* to a hardware implementation of the functionality of the software
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*
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* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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#include "mem/qos/policy_pf.hh"
#include <algorithm>
#include "base/logging.hh"
#include "params/QoSPropFairPolicy.hh"
namespace gem5
{
namespace memory
{
namespace qos
{
PropFairPolicy::PropFairPolicy(const Params &p)
: Policy(p), weight(p.weight)
{
fatal_if(weight < 0 || weight > 1,
"weight must be a value between 0 and 1");
}
PropFairPolicy::~PropFairPolicy()
{}
template <typename Requestor>
void
PropFairPolicy::initRequestor(const Requestor requestor, const double score)
{
RequestorID id = memCtrl->system()->lookupRequestorId(requestor);
assert(id != Request::invldRequestorId);
// Setting the Initial score for the selected requestor.
history.push_back(std::make_pair(id, score));
fatal_if(history.size() > memCtrl->numPriorities(),
"Policy's maximum number of requestors is currently dictated "
"by the maximum number of priorities\n");
}
void
PropFairPolicy::initRequestorName(const std::string requestor, const double score)
{
initRequestor(requestor, score);
}
void
PropFairPolicy::initRequestorObj(const SimObject* requestor, const double score)
{
initRequestor(requestor, score);
}
double
PropFairPolicy::updateScore(
const double old_score, const uint64_t served_bytes) const
{
return ((1.0 - weight) * old_score) + (weight * served_bytes);
}
uint8_t
PropFairPolicy::schedule(const RequestorID pkt_id, const uint64_t pkt_size)
{
auto sort_pred =
[] (const RequestorHistory& lhs, const RequestorHistory& rhs)
{ return lhs.second > rhs.second; };
// Sorting in reverse in base of personal history:
// First elements have higher history/score -> lower priority.
// The qos priority is the position in the sorted vector.
std::sort(history.begin(), history.end(), sort_pred);
const double served_bytes = static_cast<double>(pkt_size);
uint8_t pkt_priority = 0;
for (auto m_hist = history.begin(); m_hist != history.end(); m_hist++) {
RequestorID curr_id = m_hist->first;
double& curr_score = m_hist->second;
if (curr_id == pkt_id) {
// The qos priority is the position in the sorted vector.
pkt_priority = std::distance(history.begin(), m_hist);
curr_score = updateScore(curr_score, served_bytes);
} else {
curr_score = updateScore(curr_score, 0);
}
}
return pkt_priority;
}
} // namespace qos
} // namespace memory
} // namespace gem5