config: Add soak test for memtest.py

This patch adds a random option to memtest.py which allows the user to
easily test valid random tree topologies. The patch also adds a
wrapper script to run soak tests using the newly introduced option.

We also adjust the progress interval and progress limit check to make
the output less noisy, and avoid false positives.

Bring on the pain.

configs/example/memtest.py

@@ -40,11 +40,20 @@
 #          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",
@@ -57,14 +66,6 @@ parser.add_option("-m", "--maxtick", type="int", default=m5.MaxTick,
                   metavar="T",
                   help="Stop after T ticks")
 
-# 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.
-#
 # 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
@@ -92,8 +93,9 @@ parser.add_option("-u", "--uncacheable", type="int", default=0,
                   metavar="PCT",
                   help="Target percentage of uncacheable accesses "
                   "[default: %default]")
-
-parser.add_option("--progress", type="int", default=10000,
+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]")
@@ -108,55 +110,69 @@ 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
-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 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
 
-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"
+     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)
 
-for c in cachespec:
-     if c < 1:
-          print "Error: Must have 1 or more caches at each level"
+     if len(cachespec) < 1:
+          print "Error: Must have at least one level of caches"
           sys.exit(1)
 
-# Determine the tester multiplier for each level as the string
-# elements are per subsystem and it fans out
-multiplier = [1]
-for c in cachespec:
-     if c < 1:
-          print "Error: Must have at least one cache per level"
-     multiplier.append(multiplier[-1] * c)
+     if len(cachespec) != len(testerspec) - 1:
+          print "Error: Testers must have one element more than caches"
+          sys.exit(1)
 
-numtesters = 0
-for t, m in zip(testerspec, multiplier):
-     numtesters += t * m
+     if testerspec[-1] == 0:
+          print "Error: Must have testers at the uppermost level"
+          sys.exit(1)
 
-if numtesters > block_size:
-     print "Error: Number of testers limited to %s because of false sharing" \
-           % (block_size)
-     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 = BaseCache(size = '32kB', assoc = 4,
@@ -223,7 +239,7 @@ def make_cache_level(ncaches, prototypes, level, next_cache):
      # and also make the interval of packet injection longer for the
      # testers closer to the memory (larger level) to prevent them
      # hogging all the bandwidth
-     limit = (len(cachespec) - level + 1) * 10000000
+     limit = (len(cachespec) - level + 1) * 100000000
      testers = [proto_tester(interval = 10 * (level * level + 1),
                              progress_check = limit) \
                      for i in xrange(ntesters)]