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# Authors: Ron Dreslinski
#          Andreas Hansson

import optparse
import random
import sys

import m5
from m5.objects import *

# This example script stress tests the memory system by creating false
# sharing in a tree topology. At the bottom of the tree is a shared
# memory, and then at each level a number of testers are attached,
# along with a number of caches that them selves fan out to subtrees
# of testers and caches. Thus, it is possible to create a system with
# arbitrarily deep cache hierarchies, sharing or no sharing of caches,
# and testers not only at the L1s, but also at the L2s, L3s etc.

parser = optparse.OptionParser()

parser.add_option("-a", "--atomic", action="store_true",
                  help="Use atomic (non-timing) mode")
parser.add_option("-b", "--blocking", action="store_true",
                  help="Use blocking caches")
parser.add_option("-l", "--maxloads", metavar="N", default=0,
                  help="Stop after N loads")
parser.add_option("-m", "--maxtick", type="int", default=m5.MaxTick,
                  metavar="T",
                  help="Stop after T ticks")

# The tree specification consists of two colon-separated lists of one
# or more integers, one for the caches, and one for the testers. The
# first integer is the number of caches/testers closest to main
# memory. Each cache then fans out to a subtree. The last integer in
# the list is the number of caches/testers associated with the
# uppermost level of memory. The other integers (if any) specify the
# number of caches/testers connected at each level of the crossbar
# hierarchy. The tester string should have one element more than the
# cache string as there should always be testers attached to the
# uppermost caches.

parser.add_option("-c", "--caches", type="string", default="2:2:1",
                  help="Colon-separated cache hierarchy specification, "
                  "see script comments for details "
                  "[default: %default]")
parser.add_option("-t", "--testers", type="string", default="1:1:0:2",
                  help="Colon-separated tester hierarchy specification, "
                  "see script comments for details "
                  "[default: %default]")
parser.add_option("-f", "--functional", type="int", default=0,
                  metavar="PCT",
                  help="Target percentage of functional accesses "
                  "[default: %default]")
parser.add_option("-u", "--uncacheable", type="int", default=0,
                  metavar="PCT",
                  help="Target percentage of uncacheable accesses "
                  "[default: %default]")
parser.add_option("-r", "--random", action="store_true",
                  help="Generate a random tree topology")
parser.add_option("--progress", type="int", default=100000,
                  metavar="NLOADS",
                  help="Progress message interval "
                  "[default: %default]")
parser.add_option("--sys-clock", action="store", type="string",
                  default='1GHz',
                  help = """Top-level clock for blocks running at system
                  speed""")

(options, args) = parser.parse_args()

if args:
     print "Error: script doesn't take any positional arguments"
     sys.exit(1)

# Get the total number of testers
def numtesters(cachespec, testerspec):
     # Determine the tester multiplier for each level as the
     # elements are per subsystem and it fans out
     multiplier = [1]
     for c in cachespec:
          multiplier.append(multiplier[-1] * c)

     total = 0
     for t, m in zip(testerspec, multiplier):
          total += t * m

     return total

block_size = 64

# Start by parsing the command line options and do some basic sanity
# checking
if options.random:
     # Generate a tree with a valid number of testers
     while True:
          tree_depth = random.randint(1, 4)
          cachespec = [random.randint(1, 3) for i in range(tree_depth)]
          testerspec = [random.randint(1, 3) for i in range(tree_depth + 1)]
          if numtesters(cachespec, testerspec) < block_size:
               break

     print "Generated random tree -c", ':'.join(map(str, cachespec)), \
         "-t", ':'.join(map(str, testerspec))
else:
     try:
          cachespec = [int(x) for x in options.caches.split(':')]
          testerspec = [int(x) for x in options.testers.split(':')]
     except:
          print "Error: Unable to parse caches or testers option"
          sys.exit(1)

     if len(cachespec) < 1:
          print "Error: Must have at least one level of caches"
          sys.exit(1)

     if len(cachespec) != len(testerspec) - 1:
          print "Error: Testers must have one element more than caches"
          sys.exit(1)

     if testerspec[-1] == 0:
          print "Error: Must have testers at the uppermost level"
          sys.exit(1)

     for t in testerspec:
          if t < 0:
               print "Error: Cannot have a negative number of testers"
               sys.exit(1)

     for c in cachespec:
          if c < 1:
               print "Error: Must have 1 or more caches at each level"
               sys.exit(1)

     if numtesters(cachespec, testerspec) > block_size:
          print "Error: Limited to %s testers because of false sharing" \
              % (block_size)
          sys.exit(1)

# Define a prototype L1 cache that we scale for all successive levels
proto_l1 = Cache(size = '32kB', assoc = 4,
                 hit_latency = 1, response_latency = 1,
                 tgts_per_mshr = 8)

if options.blocking:
     proto_l1.mshrs = 1
else:
     proto_l1.mshrs = 4

cache_proto = [proto_l1]

# Now add additional cache levels (if any) by scaling L1 params, the
# first element is Ln, and the last element L1
for scale in cachespec[:-1]:
     # Clone previous level and update params
     prev = cache_proto[0]
     next = prev()
     next.size = prev.size * scale
     next.hit_latency = prev.hit_latency * 10
     next.response_latency = prev.response_latency * 10
     next.assoc = prev.assoc * scale
     next.mshrs = prev.mshrs * scale