gem5/configs/learning_gem5/part3/ruby_caches_MI_example.py

# Copyright (c) 2015 Jason Power
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#
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""" This file creates a set of Ruby caches, the Ruby network, and a simple
point-to-point topology.
See Part 3 in the Learning gem5 book:
http://gem5.org/Documentation/learning_gem5/part3/MSIintro
You can change simple_ruby to import from this file instead of from msi_caches
to use the MI_example protocol instead of MSI.

IMPORTANT: If you modify this file, it's likely that the Learning gem5 book
           also needs to be updated. For now, email Jason <jason@lowepower.com>

"""

import math

from m5.defines import buildEnv
from m5.objects import *
from m5.util import (
    fatal,
    panic,
)


class MyCacheSystem(RubySystem):
    def __init__(self):
        if "MI_example" not in buildEnv:
            fatal("This system assumes MI_example!")

        super().__init__()

    def setup(self, system, cpus, mem_ctrls):
        """Set up the Ruby cache subsystem. Note: This can't be done in the
        constructor because many of these items require a pointer to the
        ruby system (self). This causes infinite recursion in initialize()
        if we do this in the __init__.
        """
        # Ruby's global network.
        self.network = MyNetwork(self)

        # MI example uses 5 virtual networks
        self.number_of_virtual_networks = 5
        self.network.number_of_virtual_networks = 5

        # There is a single global list of all of the controllers to make it
        # easier to connect everything to the global network. This can be
        # customized depending on the topology/network requirements.
        # Create one controller for each L1 cache (and the cache mem obj.)
        # Create a single directory controller (Really the memory cntrl)
        self.controllers = [L1Cache(system, self, cpu) for cpu in cpus] + [
            DirController(self, system.mem_ranges, mem_ctrls)
        ]

        # Create one sequencer per CPU. In many systems this is more
        # complicated since you have to create sequencers for DMA controllers
        # and other controllers, too.
        self.sequencers = [
            RubySequencer(
                version=i,
                # I/D cache is combined and grab from ctrl
                dcache=self.controllers[i].cacheMemory,
                clk_domain=self.controllers[i].clk_domain,
                ruby_system=self,
            )
            for i in range(len(cpus))
        ]

        for i, c in enumerate(self.controllers[0 : len(cpus)]):
            c.sequencer = self.sequencers[i]

        self.num_of_sequencers = len(self.sequencers)

        # Create the network and connect the controllers.
        # NOTE: This is quite different if using Garnet!
        self.network.connectControllers(self.controllers)
        self.network.setup_buffers()

        # Set up a proxy port for the system_port. Used for load binaries and
        # other functional-only things.
        self.sys_port_proxy = RubyPortProxy()
        system.system_port = self.sys_port_proxy.in_ports

        # Connect the cpu's cache, interrupt, and TLB ports to Ruby
        for i, cpu in enumerate(cpus):
            self.sequencers[i].connectCpuPorts(cpu)


class L1Cache(MI_example_L1Cache_Controller):

    _version = 0

    @classmethod
    def versionCount(cls):
        cls._version += 1  # Use count for this particular type
        return cls._version - 1

    def __init__(self, system, ruby_system, cpu):
        """CPUs are needed to grab the clock domain and system is needed for
        the cache block size.
        """
        super().__init__()

        self.version = self.versionCount()
        # This is the cache memory object that stores the cache data and tags
        self.cacheMemory = RubyCache(
            size="16KiB",
            assoc=8,
            start_index_bit=self.getBlockSizeBits(system),
        )
        self.clk_domain = cpu.clk_domain
        self.send_evictions = self.sendEvicts(cpu)
        self.ruby_system = ruby_system
        self.connectQueues(ruby_system)

    def getBlockSizeBits(self, system):
        bits = int(math.log(system.cache_line_size, 2))
        if 2**bits != system.cache_line_size.value:
            panic("Cache line size not a power of 2!")
        return bits

    def sendEvicts(self, cpu):
        """True if the CPU model or ISA requires sending evictions from caches
        to the CPU. Two scenarios warrant forwarding evictions to the CPU:
        1. The O3 model must keep the LSQ coherent with the caches
        2. The x86 mwait instruction is built on top of coherence
        3. The local exclusive monitor in ARM systems

        As this is an X86 simulation we return True.
        """
        return True

    def connectQueues(self, ruby_system):
        """Connect all of the queues for this controller."""
        self.mandatoryQueue = MessageBuffer()
        self.requestFromCache = MessageBuffer(ordered=True)
        self.requestFromCache.out_port = ruby_system.network.in_port
        self.responseFromCache = MessageBuffer(ordered=True)
        self.responseFromCache.out_port = ruby_system.network.in_port
        self.forwardToCache = MessageBuffer(ordered=True)
        self.forwardToCache.in_port = ruby_system.network.out_port
        self.responseToCache = MessageBuffer(ordered=True)
        self.responseToCache.in_port = ruby_system.network.out_port


class DirController(MI_example_Directory_Controller):

    _version = 0

    @classmethod
    def versionCount(cls):
        cls._version += 1  # Use count for this particular type
        return cls._version - 1

    def __init__(self, ruby_system, ranges, mem_ctrls):
        """ranges are the memory ranges assigned to this controller."""
        if len(mem_ctrls) > 1:
            panic("This cache system can only be connected to one mem ctrl")
        super().__init__()
        self.version = self.versionCount()
        self.addr_ranges = ranges
        self.ruby_system = ruby_system
        self.directory = RubyDirectoryMemory(
            block_size=ruby_system.block_size_bytes
        )
        # Connect this directory to the memory side.
        self.memory = mem_ctrls[0].port
        self.connectQueues(ruby_system)

    def connectQueues(self, ruby_system):
        self.requestToDir = MessageBuffer(ordered=True)
        self.requestToDir.in_port = ruby_system.network.out_port
        self.dmaRequestToDir = MessageBuffer(ordered=True)
        self.dmaRequestToDir.in_port = ruby_system.network.out_port

        self.responseFromDir = MessageBuffer()
        self.responseFromDir.out_port = ruby_system.network.in_port
        self.dmaResponseFromDir = MessageBuffer(ordered=True)
        self.dmaResponseFromDir.out_port = ruby_system.network.in_port
        self.forwardFromDir = MessageBuffer()
        self.forwardFromDir.out_port = ruby_system.network.in_port
        self.requestToMemory = MessageBuffer()
        self.responseFromMemory = MessageBuffer()


class MyNetwork(SimpleNetwork):
    """A simple point-to-point network. This doesn't not use garnet."""

    def __init__(self, ruby_system):
        super().__init__()
        self.netifs = []
        self.ruby_system = ruby_system

    def connectControllers(self, controllers):
        """Connect all of the controllers to routers and connec the routers
        together in a point-to-point network.
        """
        # Create one router/switch per controller in the system
        self.routers = [Switch(router_id=i) for i in range(len(controllers))]

        # Make a link from each controller to the router. The link goes
        # externally to the network.
        self.ext_links = [
            SimpleExtLink(link_id=i, ext_node=c, int_node=self.routers[i])
            for i, c in enumerate(controllers)
        ]

        # Make an "internal" link (internal to the network) between every pair
        # of routers.
        link_count = 0
        int_links = []
        for ri in self.routers:
            for rj in self.routers:
                if ri == rj:
                    continue  # Don't connect a router to itself!
                link_count += 1
                int_links.append(
                    SimpleIntLink(link_id=link_count, src_node=ri, dst_node=rj)
                )
        self.int_links = int_links