Prefetcher.py revision 13427 
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13# Copyright (c) 2005 The Regents of The University of Michigan
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38#
39# Authors: Ron Dreslinski
40#          Mitch Hayenga
41
42from ClockedObject import ClockedObject
43from m5.SimObject import *
44from m5.params import *
45from m5.proxy import *
46from ReplacementPolicies import *
47
48class HWPProbeEvent(object):
49    def __init__(self, prefetcher, obj, *listOfNames):
50        self.obj = obj
51        self.prefetcher = prefetcher
52        self.names = listOfNames
53
54    def register(self):
55        if self.obj:
56            for name in self.names:
57                self.prefetcher.getCCObject().addEventProbe(
58                    self.obj.getCCObject(), name)
59
60class BasePrefetcher(ClockedObject):
61    type = 'BasePrefetcher'
62    abstract = True
63    cxx_header = "mem/cache/prefetch/base.hh"
64    cxx_exports = [
65        PyBindMethod("addEventProbe"),
66    ]
67    sys = Param.System(Parent.any, "System this prefetcher belongs to")
68
69    # Get the block size from the parent (system)
70    block_size = Param.Int(Parent.cache_line_size, "Block size in bytes")
71
72    on_miss = Param.Bool(False, "Only notify prefetcher on misses")
73    on_read = Param.Bool(True, "Notify prefetcher on reads")
74    on_write = Param.Bool(True, "Notify prefetcher on writes")
75    on_data  = Param.Bool(True, "Notify prefetcher on data accesses")
76    on_inst  = Param.Bool(True, "Notify prefetcher on instruction accesses")
77    prefetch_on_access = Param.Bool(Parent.prefetch_on_access,
78        "Notify the hardware prefetcher on every access (not just misses)")
79
80    _events = []
81    def addEvent(self, newObject):
82        self._events.append(newObject)
83
84    # Override the normal SimObject::regProbeListeners method and
85    # register deferred event handlers.
86    def regProbeListeners(self):
87        for event in self._events:
88           event.register()
89        self.getCCObject().regProbeListeners()
90
91    def listenFromProbe(self, simObj, *probeNames):
92        if not isinstance(simObj, SimObject):
93            raise TypeError("argument must be of SimObject type")
94        if len(probeNames) <= 0:
95            raise TypeError("probeNames must have at least one element")
96        self.addEvent(HWPProbeEvent(self, simObj, *probeNames))
97
98class QueuedPrefetcher(BasePrefetcher):
99    type = "QueuedPrefetcher"
100    abstract = True
101    cxx_class = "QueuedPrefetcher"
102    cxx_header = "mem/cache/prefetch/queued.hh"
103    latency = Param.Int(1, "Latency for generated prefetches")
104    queue_size = Param.Int(32, "Maximum number of queued prefetches")
105    queue_squash = Param.Bool(True, "Squash queued prefetch on demand access")
106    queue_filter = Param.Bool(True, "Don't queue redundant prefetches")
107    cache_snoop = Param.Bool(False, "Snoop cache to eliminate redundant request")
108
109    tag_prefetch = Param.Bool(True, "Tag prefetch with PC of generating access")
110
111class StridePrefetcher(QueuedPrefetcher):
112    type = 'StridePrefetcher'
113    cxx_class = 'StridePrefetcher'
114    cxx_header = "mem/cache/prefetch/stride.hh"
115
116    # Do not consult stride prefetcher on instruction accesses
117    on_inst = False
118
119    max_conf = Param.Int(7, "Maximum confidence level")
120    thresh_conf = Param.Int(4, "Threshold confidence level")
121    min_conf = Param.Int(0, "Minimum confidence level")
122    start_conf = Param.Int(4, "Starting confidence for new entries")
123
124    table_sets = Param.Int(16, "Number of sets in PC lookup table")
125    table_assoc = Param.Int(4, "Associativity of PC lookup table")
126    use_master_id = Param.Bool(True, "Use master id based history")
127
128    degree = Param.Int(4, "Number of prefetches to generate")
129
130    # Get replacement policy
131    replacement_policy = Param.BaseReplacementPolicy(RandomRP(),
132        "Replacement policy")
133
134class TaggedPrefetcher(QueuedPrefetcher):
135    type = 'TaggedPrefetcher'
136    cxx_class = 'TaggedPrefetcher'
137    cxx_header = "mem/cache/prefetch/tagged.hh"
138
139    degree = Param.Int(2, "Number of prefetches to generate")
140