gem5/src/mem/ruby/system/Sequencer.py
Joel Hestness 9567c839fe ruby: Remove the RubyCache/CacheMemory latency
The RubyCache (CacheMemory) latency parameter is only used for top-level caches
instantiated for Ruby coherence protocols. However, the top-level cache hit
latency is assessed by the Sequencer as accesses flow through to the cache
hierarchy. Further, protocol state machines should be enforcing these cache hit
latencies, but RubyCaches do not expose their latency to any existng state
machines through the SLICC/C++ interface. Thus, the RubyCache latency parameter
is superfluous for all caches. This is confusing for users.

As a step toward pushing L0/L1 cache hit latency into the top-level cache
controllers, move their latencies out of the RubyCache declarations and over to
their Sequencers. Eventually, these Sequencer parameters should be exposed as
parameters to the top-level cache controllers, which should assess the latency.
NOTE: Assessing these latencies in the cache controllers will require modifying
each to eliminate instantaneous Ruby hit callbacks in transitions that finish
accesses, which is likely a large undertaking.
2015-08-14 00:19:37 -05:00

84 lines
3.7 KiB
Python

# Copyright (c) 2009 Advanced Micro Devices, Inc.
# All rights reserved.
#
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# met: redistributions of source code must retain the above copyright
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# neither the name of the copyright holders nor the names of its
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# this software without specific prior written permission.
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
# Authors: Steve Reinhardt
# Brad Beckmann
from m5.params import *
from m5.proxy import *
from MemObject import MemObject
class RubyPort(MemObject):
type = 'RubyPort'
abstract = True
cxx_header = "mem/ruby/system/RubyPort.hh"
version = Param.Int(0, "")
slave = VectorSlavePort("CPU slave port")
master = VectorMasterPort("CPU master port")
pio_master_port = MasterPort("Ruby mem master port")
mem_master_port = MasterPort("Ruby mem master port")
pio_slave_port = SlavePort("Ruby pio slave port")
mem_slave_port = SlavePort("Ruby memory port")
using_ruby_tester = Param.Bool(False, "")
ruby_system = Param.RubySystem(Parent.any, "")
system = Param.System(Parent.any, "system object")
support_data_reqs = Param.Bool(True, "data cache requests supported")
support_inst_reqs = Param.Bool(True, "inst cache requests supported")
class RubyPortProxy(RubyPort):
type = 'RubyPortProxy'
cxx_header = "mem/ruby/system/RubyPortProxy.hh"
class RubySequencer(RubyPort):
type = 'RubySequencer'
cxx_class = 'Sequencer'
cxx_header = "mem/ruby/system/Sequencer.hh"
icache = Param.RubyCache("")
dcache = Param.RubyCache("")
# Cache latencies currently assessed at the beginning of each access
# NOTE: Setting these values to a value greater than one will result in
# O3 CPU pipeline bubbles and negatively impact performance
# TODO: Latencies should be migrated into each top-level cache controller
icache_hit_latency = Param.Cycles(1, "Inst cache hit latency")
dcache_hit_latency = Param.Cycles(1, "Data cache hit latency")
max_outstanding_requests = Param.Int(16,
"max requests (incl. prefetches) outstanding")
deadlock_threshold = Param.Cycles(500000,
"max outstanding cycles for a request before deadlock/livelock declared")
using_network_tester = Param.Bool(False, "")
class DMASequencer(MemObject):
type = 'DMASequencer'
cxx_header = "mem/ruby/system/DMASequencer.hh"
version = Param.Int(0, "")
slave = SlavePort("Device slave port")
using_ruby_tester = Param.Bool(False, "")
ruby_system = Param.RubySystem(Parent.any, "")
system = Param.System(Parent.any, "system object")