Prefetcher.py revision 13551:f352df8e2863 
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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    use_virtual_addresses = Param.Bool(False,
80        "Use virtual addresses for prefetching")
81
82    _events = []
83    def addEvent(self, newObject):
84        self._events.append(newObject)
85
86    # Override the normal SimObject::regProbeListeners method and
87    # register deferred event handlers.
88    def regProbeListeners(self):
89        for event in self._events:
90           event.register()
91        self.getCCObject().regProbeListeners()
92
93    def listenFromProbe(self, simObj, *probeNames):
94        if not isinstance(simObj, SimObject):
95            raise TypeError("argument must be of SimObject type")
96        if len(probeNames) <= 0:
97            raise TypeError("probeNames must have at least one element")
98        self.addEvent(HWPProbeEvent(self, simObj, *probeNames))
99
100class QueuedPrefetcher(BasePrefetcher):
101    type = "QueuedPrefetcher"
102    abstract = True
103    cxx_class = "QueuedPrefetcher"
104    cxx_header = "mem/cache/prefetch/queued.hh"
105    latency = Param.Int(1, "Latency for generated prefetches")
106    queue_size = Param.Int(32, "Maximum number of queued prefetches")
107    queue_squash = Param.Bool(True, "Squash queued prefetch on demand access")
108    queue_filter = Param.Bool(True, "Don't queue redundant prefetches")
109    cache_snoop = Param.Bool(False, "Snoop cache to eliminate redundant request")
110
111    tag_prefetch = Param.Bool(True, "Tag prefetch with PC of generating access")
112
113class StridePrefetcher(QueuedPrefetcher):
114    type = 'StridePrefetcher'
115    cxx_class = 'StridePrefetcher'
116    cxx_header = "mem/cache/prefetch/stride.hh"
117
118    # Do not consult stride prefetcher on instruction accesses
119    on_inst = False
120
121    max_conf = Param.Int(7, "Maximum confidence level")
122    thresh_conf = Param.Int(4, "Threshold confidence level")
123    min_conf = Param.Int(0, "Minimum confidence level")
124    start_conf = Param.Int(4, "Starting confidence for new entries")
125
126    table_sets = Param.Int(16, "Number of sets in PC lookup table")
127    table_assoc = Param.Int(4, "Associativity of PC lookup table")
128    use_master_id = Param.Bool(True, "Use master id based history")
129
130    degree = Param.Int(4, "Number of prefetches to generate")
131
132    # Get replacement policy
133    replacement_policy = Param.BaseReplacementPolicy(RandomRP(),
134        "Replacement policy")
135
136class TaggedPrefetcher(QueuedPrefetcher):
137    type = 'TaggedPrefetcher'
138    cxx_class = 'TaggedPrefetcher'
139    cxx_header = "mem/cache/prefetch/tagged.hh"
140
141    degree = Param.Int(2, "Number of prefetches to generate")
142