gem5  v22.0.0.2
q_policy.cc
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37 
38 #include "mem/qos/q_policy.hh"
39 
40 #include <unordered_map>
41 #include <utility>
42 
43 #include "base/logging.hh"
44 #include "base/trace.hh"
45 #include "debug/QOS.hh"
46 #include "enums/QoSQPolicy.hh"
47 #include "mem/request.hh"
48 
49 namespace gem5
50 {
51 
52 namespace memory
53 {
54 
56 namespace qos
57 {
58 
59 QueuePolicy*
60 QueuePolicy::create(const QoSMemCtrlParams &p)
61 {
62  switch (p.qos_q_policy) {
63  case enums::QoSQPolicy::fifo:
64  return new FifoQueuePolicy(p);
65  case enums::QoSQPolicy::lrg:
66  return new LrgQueuePolicy(p);
67  case enums::QoSQPolicy::lifo:
68  default:
69  return new LifoQueuePolicy(p);
70  }
71 }
72 
73 QueuePolicy::PacketQueue::iterator
75 {
76  QueuePolicy::PacketQueue::iterator ret = q->end();
77 
78  // Tracks one packet per requestor in the queue
79  std::unordered_map<RequestorID, QueuePolicy::PacketQueue::iterator> track;
80 
81  // Cycle queue only once
82  for (auto pkt_it = q->begin(); pkt_it != q->end(); ++pkt_it) {
83 
84  const auto& pkt = *pkt_it;
85 
86  panic_if(!pkt->req,
87  "QoSQPolicy::lrg detected packet without request");
88 
89  // Get Request RequestorID
90  RequestorID requestor_id = pkt->req->requestorId();
91  DPRINTF(QOS, "QoSQPolicy::lrg checking packet "
92  "from queue with id %d\n", requestor_id);
93 
94  // Check if this is a known requestor.
95  panic_if(memCtrl->hasRequestor(requestor_id),
96  "%s: Unrecognized Requestor\n", __func__);
97 
98  panic_if(toServe.size() > 0,
99  "%s: toServe list is empty\n", __func__);
100 
101  if (toServe.front() == requestor_id) {
102  DPRINTF(QOS, "QoSQPolicy::lrg matched to served "
103  "requestor id %d\n", requestor_id);
104  // This packet matches the RequestorID to be served next
105  // move toServe front to back
106  toServe.push_back(requestor_id);
107  toServe.pop_front();
108 
109  return pkt_it;
110  }
111 
112  // The requestor generating the packet is not first in the toServe list
113  // (Doesn't have the highest priority among requestors)
114  // Check if this is the first packet seen with its requestor id
115  // and remember it. Then keep looping over the remaining packets
116  // in the queue.
117  if (track.find(requestor_id) == track.end()) {
118  track[requestor_id] = pkt_it;
119  DPRINTF(QOS, "QoSQPolicy::lrg tracking a packet for "
120  "requestor id %d\n", requestor_id);
121  }
122  }
123 
124  // If here, the current requestor to be serviced doesn't have a pending
125  // packet in the queue: look for the next requestor in the list.
126  for (const auto& requestorId : toServe) {
127  DPRINTF(QOS, "QoSQPolicy::lrg evaluating alternative "
128  "requestor id %d\n", requestorId);
129 
130  if (track.find(requestorId) != track.end()) {
131  ret = track[requestorId];
132  DPRINTF(QOS, "QoSQPolicy::lrg requestor id "
133  "%d selected for service\n", requestorId);
134 
135  return ret;
136  }
137  }
138 
139  DPRINTF(QOS, "QoSQPolicy::lrg no packet was serviced\n");
140 
141  // Ret will be : packet to serve if any found or queue begin
142  // (end if queue is empty)
143  return ret;
144 }
145 
146 void
148 {
149  RequestorID requestor_id = pkt->requestorId();
150  if (!memCtrl->hasRequestor(requestor_id)) {
151  toServe.push_back(requestor_id);
152  }
153 };
154 
155 } // namespace qos
156 } // namespace memory
157 } // namespace gem5
memory
Definition: mem.h:38
gem5::memory::qos::LrgQueuePolicy::selectPacket
PacketQueue::iterator selectPacket(PacketQueue *queue) override
Implements LRG packet select policy.
Definition: q_policy.cc:74
gem5::memory::qos::QueuePolicy::create
static QueuePolicy * create(const QoSMemCtrlParams &p)
This factory method is used for generating the queue policy.
Definition: q_policy.cc:60
gem5::memory::GEM5_DEPRECATED_NAMESPACE
GEM5_DEPRECATED_NAMESPACE(QoS, qos)
q_policy.hh
gem5::memory::qos::LifoQueuePolicy
Last In First Out Queue Policy.
Definition: q_policy.hh:121
gem5::memory::qos::FifoQueuePolicy
First In First Out Queue Policy.
Definition: q_policy.hh:142
request.hh
gem5::memory::qos::MemCtrl::hasRequestor
bool hasRequestor(RequestorID id) const
hasRequestor returns true if the selected requestor(ID) has been registered in the memory controller,...
Definition: mem_ctrl.hh:316
gem5::Packet::requestorId
RequestorID requestorId() const
Definition: packet.hh:776
gem5::VegaISA::p
Bitfield< 54 > p
Definition: pagetable.hh:70
DPRINTF
#define DPRINTF(x,...)
Definition: trace.hh:186
gem5::Packet
A Packet is used to encapsulate a transfer between two objects in the memory system (e....
Definition: packet.hh:291
gem5::memory::qos::QueuePolicy::memCtrl
MemCtrl * memCtrl
Pointer to parent memory controller implementing the policy.
Definition: q_policy.hh:117
gem5::memory::qos::LrgQueuePolicy
Least Recently Granted Queue Policy It selects packets from the queue with a round robin-like policy:...
Definition: q_policy.hh:168
gem5::memory::qos::LrgQueuePolicy::enqueuePacket
void enqueuePacket(PacketPtr pkt) override
This method is called by the memory controller after it enqueues a packet.
Definition: q_policy.cc:147
panic_if
#define panic_if(cond,...)
Conditional panic macro that checks the supplied condition and only panics if the condition is true a...
Definition: logging.hh:204
gem5::ArmISA::q
Bitfield< 27 > q
Definition: misc_types.hh:55
std::deque
STL deque class.
Definition: stl.hh:44
logging.hh
gem5::RequestorID
uint16_t RequestorID
Definition: request.hh:95
trace.hh
gem5
Reference material can be found at the JEDEC website: UFS standard http://www.jedec....
Definition: gpu_translation_state.hh:37
gem5::memory::qos::LrgQueuePolicy::toServe
std::list< RequestorID > toServe
Support structure for lrg algorithms: keeps track of serviced requestors, always serve the front elem...
Definition: q_policy.hh:192

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