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"""
Script to run SPEC CPU2006 benchmarks with gem5.
The script expects a benchmark program name and the simulation
size. The system is fixed with 2 CPU cores, MESI Two Level system
cache and 3 GB DDR4 memory. It uses the x86 board.

This script will count the total number of instructions executed
in the ROI. It also tracks how much wallclock and simulated time.

Usage:
------

```
scons build/X86/gem5.opt
./build/X86/gem5.opt \
    configs/example/gem5_library/x86-spec-cpu2006-benchmarks.py \
    --image <full_path_to_the_spec-2006_disk_image> \
    --partition <root_partition_to_mount> \
    --benchmark <benchmark_name> \
    --size <simulation_size>
```

"""

import argparse
import time
import os
import json

import m5
from m5.objects import Root

from gem5.utils.requires import requires
from gem5.components.boards.x86_board import X86Board
from gem5.components.memory import DualChannelDDR4_2400
from gem5.components.processors.simple_switchable_processor import(
    SimpleSwitchableProcessor,
)
from gem5.components.processors.cpu_types import CPUTypes
from gem5.isas import ISA
from gem5.coherence_protocol import CoherenceProtocol
from gem5.resources.resource import Resource, CustomDiskImageResource

from m5.stats.gem5stats import get_simstat
from m5.util import warn
from m5.util import fatal

# We check for the required gem5 build.

requires(
    isa_required=ISA.X86,
    coherence_protocol_required=CoherenceProtocol.MESI_TWO_LEVEL,
    kvm_required=True,
)

# Following are the list of benchmark programs for SPEC CPU2006.
# Note that 400.perlbench, 447.dealII, 450.soplex and 483.xalancbmk
# have build errors, and, therefore cannot be executed. More information is
# available at: https://www.gem5.org/documentation/benchmark_status/gem5-20

benchmark_choices = ['400.perlbench', '401.bzip2', '403.gcc', '410.bwaves',
                    '416.gamess', '429.mcf', '433.milc', '435.gromacs',
                    '436.cactusADM', '437.leslie3d', '444.namd', '445.gobmk',
                    '447.dealII', '450.soplex', '453.povray', '454.calculix',
                    '456.hmmer', '458.sjeng', '459.GemsFDTD',
                    '462.libquantum', '464.h264ref', '465.tonto', '470.lbm',
                    '471.omnetpp', '473.astar', '481.wrf', '482.sphinx3',
                    '483.xalancbmk', '998.specrand', '999.specrand']

# Following are the input size.

size_choices = ["test", "train", "ref"]

parser = argparse.ArgumentParser(
    description="An example configuration script to run the \
        SPEC CPU2006 benchmarks."
)

# The arguments accepted are: a. disk-image name, b. benchmark name, c.
# simulation size, and, d. root partition.

# root partition is set to 1 by default.

parser.add_argument(
    "--image",
    type = str,
    required = True,
    help = "Input the full path to the built spec-2006 disk-image."
)

parser.add_argument(
    "--partition",
    type = str,
    required = False,
    default=None,
    help = "Input the root partition of the SPEC disk-image. If the disk is \
    not partitioned, then pass \"\"."
)

parser.add_argument(
    "--benchmark",
    type = str,
    required=True,
    help = "Input the benchmark program to execute.",
    choices=benchmark_choices,
)

parser.add_argument(
    "--size",
    type = str,
    required=True,
    help = "Sumulation size the benchmark program.",
    choices = size_choices,
)

args = parser.parse_args()

# We expect the user to input the full path of the disk-image.
if args.image[0] != "/":
    # We need to get the absolute path to this file. We assume that the file is
    # present on the current working directory.
    args.image = os.path.abspath(args.image)

if not os.path.exists(args.image):
    warn("Disk image not found!")
    print("Instructions on building the disk image can be found at: ")
    print(
    "https://gem5art.readthedocs.io/en/latest/tutorials/spec-tutorial.html"
    )
    fatal("The disk-image is not found at {}".format(args.image))

# Setting up all the fixed system parameters here
# Caches: MESI Two Level Cache Hierarchy

from gem5.components.cachehierarchies.ruby.\
    mesi_two_level_cache_hierarchy import(
    MESITwoLevelCacheHierarchy,
)

cache_hierarchy = MESITwoLevelCacheHierarchy(
    l1d_size = "32kB",
    l1d_assoc = 8,
    l1i_size="32kB",
    l1i_assoc=8,
    l2_size="256kB",
    l2_assoc=16,
    num_l2_banks=2,
)
# Memory: Dual Channel DDR4 2400 DRAM device.
# The X86 board only supports 3 GB of main memory.

memory = DualChannelDDR4_2400(size = "3GB")

# Here we setup the processor. This is a special switchable processor in which
# a starting core type and a switch core type must be specified. Once a
# configuration is instantiated a user may call `processor.switch()` to switch
# from the starting core types to the switch core types. In this simulation
# we start with KVM cores to simulate the OS boot, then switch to the Timing
# cores for the command we wish to run after boot.

processor = SimpleSwitchableProcessor(
    starting_core_type=CPUTypes.KVM,
    switch_core_type=CPUTypes.TIMING,
    num_cores=2,
)

# Here we setup the board. The X86Board allows for Full-System X86 simulations

board = X86Board(
    clk_freq="3GHz",
    processor=processor,
    memory=memory,
    cache_hierarchy=cache_hierarchy,
)

# SPEC CPU2006 benchmarks output placed in /home/gem5/spec2006/results
# directory on the disk-image. The following folder is created in the
# m5.options.outdir and the output from the disk-image folder is copied to
# this folder.

output_dir = "speclogs_" + ''.join(x.strip() for x in time.asctime().split())
output_dir = output_dir.replace(":","")

# We create this folder if it is absent.
try:
    os.makedirs(os.path.join(m5.options.outdir, output_dir))
except FileExistsError:
    warn("output directory already exists!")

# Here we set the FS workload, i.e., SPEC CPU2006 benchmark
# After simulation has ended you may inspect
# `m5out/system.pc.com_1.device` to the stdout, if any.

# After the system boots, we execute the benchmark program and wait till the
# `m5_exit instruction encountered` is encountered. We start collecting
# the number of committed instructions till ROI ends (marked by another
# `m5_exit instruction encountered`). We then start copying the output logs,
# present in the /home/gem5/spec2006/results directory to the `output_dir`.

# The runscript.sh file places `m5 exit` before and after the following command
# Therefore, we only pass this command without m5 exit.

command = "{} {} {}".format(args.benchmark, args.size, output_dir)

board.set_kernel_disk_workload(
    # The x86 linux kernel will be automatically downloaded to the
    # `~/.cache/gem5` directory if not already present.
    # SPEC CPU2006 benchamarks were tested with kernel version 4.19.83 and
    # 5.4.49
    kernel=Resource(
        "x86-linux-kernel-4.19.83",
    ),
    # The location of the x86 SPEC CPU 2017 image
    disk_image=CustomDiskImageResource(
        args.image,
        disk_root_partition=args.partition,
    ),
    readfile_contents=command,
)

# We need this for long running processes.
m5.disableAllListeners()

root = Root(full_system = True, system = board)

# sim_quantum must be set when KVM cores are used.

root.sim_quantum = int(1e9)

m5.instantiate()

# We maintain the wall clock time.

globalStart = time.time()

print("Running the simulation")
print("Using KVM cpu")

start_tick = m5.curTick()
end_tick = m5.curTick()
m5.stats.reset()

exit_event = m5.simulate()

if exit_event.getCause() == "m5_exit instruction encountered":
    # We have completed booting the OS using KVM cpu
    # Reached the start of ROI

    print("Done booting Linux")
    print("Resetting stats at the start of ROI!")

    m5.stats.reset()
    start_tick = m5.curTick()

    # We switch to timing cpu for detailed simulation.

    processor.switch()
else:
    # `m5_exit instruction encountered` was never reached

    print("Unexpected termination of simulation before ROI was reached!")
    print(
        "Exiting @ tick {} because {}.".format(
            m5.curTick(),
            exit_event.getCause()
        )
    )
    exit(-1)

# Simulate the ROI
exit_event = m5.simulate()

# Reached the end of ROI
gem5stats = get_simstat(root)

# We get the number of committed instructions from the timing
# cores. We then sum and print them at the end.

roi_insts = float(\
    json.loads(gem5stats.dumps())\
    ["system"]["processor"]["cores2"]["core"]["exec_context.thread_0"]\
    ["numInsts"]["value"]) + float(\
    json.loads(gem5stats.dumps())\
    ["system"]["processor"]["cores3"]["core"]["exec_context.thread_0"]\
    ["numInsts"]["value"]\
)

if exit_event.getCause() == "m5_exit instruction encountered":
    print("Dump stats at the end of the ROI!")
    m5.stats.dump()
    end_tick = m5.curTick()
    m5.stats.reset()

else:
    # `m5_exit instruction encountered` was never reached

    print("Unexpected termination of simulation while ROI was being executed!")
    print(
        "Exiting @ tick {} because {}.".format(
            m5.curTick(),
            exit_event.getCause()
        )
    )
    exit(-1)

# We need to copy back the contents of the `speclogs' directory to
# m5.options.outdir

exit_event = m5.simulate()

if exit_event.getCause() == "m5_exit instruction encountered":
    print("Output logs copied!")

else:
    print("Unexpected termination of simulation while copying speclogs!")
    print(
        "Exiting @ tick {} because {}.".format(
            m5.curTick(),
            exit_event.getCause()
        )
    )
    exit(-1)

m5.stats.dump()
end_tick = m5.curTick()
m5.stats.reset()

# Simulation is over at this point. We acknowledge that all the simulation
# events were successful.
print("All simulation events were successful.")
# We print the final simulation statistics.

print("Performance statistics:")

print("Simulated time: %.2fs" % ((end_tick-start_tick)/1e12))
print("Instructions executed: %d" % ((roi_insts)))
print("Ran a total of", m5.curTick()/1e12, "simulated seconds")
print("Total wallclock time: %.2fs, %.2f min" % \
            (time.time()-globalStart, (time.time()-globalStart)/60))