xref: /gem5/src/mem/cache/prefetch/Prefetcher.py

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# Authors: Ron Dreslinski
#          Mitch Hayenga

from ClockedObject import ClockedObject
from m5.params import *
from m5.proxy import *

class BasePrefetcher(ClockedObject):
    type = 'BasePrefetcher'
    abstract = True
    cxx_header = "mem/cache/prefetch/base.hh"
    sys = Param.System(Parent.any, "System this prefetcher belongs to")

    on_miss = Param.Bool(False, "Only notify prefetcher on misses")
    on_read = Param.Bool(True, "Notify prefetcher on reads")
    on_write = Param.Bool(True, "Notify prefetcher on writes")
    on_data  = Param.Bool(True, "Notify prefetcher on data accesses")
    on_inst  = Param.Bool(True, "Notify prefetcher on instruction accesses")

class QueuedPrefetcher(BasePrefetcher):
    type = "QueuedPrefetcher"
    abstract = True
    cxx_class = "QueuedPrefetcher"
    cxx_header = "mem/cache/prefetch/queued.hh"
    latency = Param.Int(1, "Latency for generated prefetches")
    queue_size = Param.Int(32, "Maximum number of queued prefetches")
    queue_squash = Param.Bool(True, "Squash queued prefetch on demand access")
    queue_filter = Param.Bool(True, "Don't queue redundant prefetches")
    cache_snoop = Param.Bool(False, "Snoop cache to eliminate redundant request")

    tag_prefetch = Param.Bool(True, "Tag prefetch with PC of generating access")

class StridePrefetcher(QueuedPrefetcher):
    type = 'StridePrefetcher'
    cxx_class = 'StridePrefetcher'
    cxx_header = "mem/cache/prefetch/stride.hh"

    max_conf = Param.Int(7, "Maximum confidence level")
    thresh_conf = Param.Int(4, "Threshold confidence level")
    min_conf = Param.Int(0, "Minimum confidence level")
    start_conf = Param.Int(4, "Starting confidence for new entries")

    table_sets = Param.Int(16, "Number of sets in PC lookup table")
    table_assoc = Param.Int(4, "Associativity of PC lookup table")
    use_master_id = Param.Bool(True, "Use master id based history")

    degree = Param.Int(4, "Number of prefetches to generate")

class TaggedPrefetcher(QueuedPrefetcher):
    type = 'TaggedPrefetcher'
    cxx_class = 'TaggedPrefetcher'
    cxx_header = "mem/cache/prefetch/tagged.hh"

    degree = Param.Int(2, "Number of prefetches to generate")