src/mem/qos/policy_pf.hh

/*
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#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
{

GEM5_DEPRECATED_NAMESPACE(QoS, qos);
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__