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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
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef __MEM_QOS_POLICY_PF_HH__
#define __MEM_QOS_POLICY_PF_HH__
#include <vector>
#include "base/compiler.hh"
#include "mem/qos/policy.hh"
#include "mem/request.hh"
namespace gem5
{
struct QoSPropFairPolicyParams;
namespace memory
{
namespace qos
{
/**
* Proportional Fair QoS Policy
* Providing a configurable fair scheduling policy based on
* utilization; utilization is directly proportional to a
* score which is inversely proportional to the QoS priority
* Users can tune the policy by adjusting the weight parameter
* (weight of the formula)
*
* This is the formula used by the policy
* ((1.0 - weight) * old_score) + (weight * served_bytes);
*/
class PropFairPolicy : public Policy
{
using Params = QoSPropFairPolicyParams;
public:
PropFairPolicy(const Params &);
virtual ~PropFairPolicy();
/**
* Initialize the requestor's score by providing
* the requestor's name and initial score value.
* The requestor's name has to match a name in the system.
*
* @param requestor requestor's name to lookup.
* @param score initial score value for the requestor
*/
void initRequestorName(const std::string requestor, const double score);
/**
* Initialize the requestor's score by providing
* the requestor's SimObject pointer and initial score value.
* The requestor's pointer has to match a requestor in the system.
*
* @param requestor requestor's SimObject pointer to lookup.
* @param score initial score value for the requestor
*/
void initRequestorObj(const SimObject* requestor, const double score);
/**
* Schedules a packet based on proportional fair configuration
*
* @param id requestor id to schedule
* @param pkt_size size of the packet
* @return QoS priority value
*/
virtual uint8_t
schedule(const RequestorID id, const uint64_t pkt_size) override;
protected:
template <typename Requestor>
void initRequestor(const Requestor requestor, const double score);
inline double
updateScore(const double old_score, const uint64_t served_bytes) const;
protected:
/** PF Policy weight */
const double weight;
/** history is keeping track of every requestor's score */
using RequestorHistory = std::pair<RequestorID, double>;
std::vector<RequestorHistory> history;
};
} // namespace qos
} // namespace memory
} // namespace gem5
#endif // __MEM_QOS_POLICY_PF_HH__