config: add --param to fs.py, se.py and fs_bigLITTLE.py

The option allows to set SimObject params from the CLI.

The existing config scripts have a large number of options that simply set
a single SimObject parameter, and many still are not exposed.

This commit allows users to pass arbitrary parameters from the command
line to prevent the need for this kind of trivial option.

Change-Id: Ic4bd36948aca4998d2eaf6369c85d3668efa3944
Reviewed-on: https://gem5-review.googlesource.com/c/12985
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

configs/common/Options.py

@@ -125,6 +125,14 @@ def addNoISAOptions(parser):
     parser.add_option("--maxtime", type="float", default=None,
                       help="Run to the specified absolute simulated time in "
                       "seconds")
+    parser.add_option("-P", "--param", action="append", default=[],
+        help="Set a SimObject parameter relative to the root node. "
+             "An extended Python multi range slicing syntax can be used "
+             "for arrays. For example: "
+             "'system.cpu[0,1,3:8:2].max_insts_all_threads = 42' "
+             "sets max_insts_all_threads for cpus 0, 1, 3, 5 and 7 "
+             "Direct parameters of the root object are not accessible, "
+             "only parameters of its children.")
 
 # Add common options that assume a non-NULL ISA.
 def addCommonOptions(parser):

configs/common/Simulation.py

@@ -597,6 +597,7 @@ def run(options, root, testsys, cpu_class):
     checkpoint_dir = None
     if options.checkpoint_restore:
         cpt_starttick, checkpoint_dir = findCptDir(options, cptdir, testsys)
+    root.apply_config(options.param)
     m5.instantiate(checkpoint_dir)
 
     # Initialization is complete.  If we're not in control of simulation

configs/example/arm/fs_bigLITTLE.py

@@ -182,6 +182,14 @@ def addOptions(parser):
     parser.add_argument("--sim-quantum", type=str, default="1ms",
                         help="Simulation quantum for parallel simulation. " \
                         "Default: %(default)s")
+    parser.add_argument("-P", "--param", action="append", default=[],
+        help="Set a SimObject parameter relative to the root node. "
+             "An extended Python multi range slicing syntax can be used "
+             "for arrays. For example: "
+             "'system.cpu[0,1,3:8:2].max_insts_all_threads = 42' "
+             "sets max_insts_all_threads for cpus 0, 1, 3, 5 and 7 "
+             "Direct parameters of the root object are not accessible, "
+             "only parameters of its children.")
     return parser
 
 def build(options):
@@ -330,6 +338,7 @@ def main():
     addOptions(parser)
     options = parser.parse_args()
     root = build(options)
+    root.apply_config(options.param)
     instantiate(options)
     run()