Revert "orchestration/simulators.py: speed up simulations using gem5 checkpoints"

The solution here was quite hacky in that we modified gem5's checkpoint file to have a timestamp of 0. This actually breaks when simulating a Linux host and conducting time measurements. The numbers you get will end up all over the place.

experiments/simbricks/orchestration/experiment/experiment_environment.py

@@ -40,9 +40,6 @@ class ExpEnv(object):
         self.workdir = os.path.abspath(workdir)
         self.cpdir = os.path.abspath(cpdir)
         self.shm_base = self.workdir
-        self.utilsdir = f'{self.repodir}/experiments/simbricks/utils'
-        """Directory containing some utility scripts/binaries."""
-
         self.qemu_img_path = f'{self.repodir}/sims/external/qemu/build/qemu-img'
         self.qemu_path = (
             f'{self.repodir}/sims/external/qemu/build/'

experiments/simbricks/orchestration/simulators.py

@@ -458,17 +458,6 @@ class Gem5Host(HostSim):
         self.extra_main_args = []
         self.extra_config_args = []
         self.variant = 'fast'
-        self.modify_checkpoint_tick = True
-        """
-        Whether to modify the event queue tick before restoring a checkpoint.
-
-        When this is enabled, the restored checkpoint will start at event queue
-        tick 0. This is a performance optimization since now, connected
-        simulators don't have to simulate and synchronize until the restored
-        tick before the actual workload can be executed. Disable this if you
-        need to retain the differences in virtual time between multiple gem5
-        instances.
-        """
 
     def resreq_cores(self) -> int:
         return 1
@@ -477,13 +466,7 @@ class Gem5Host(HostSim):
         return 4096
 
     def prep_cmds(self, env: ExpEnv) -> tp.List[str]:
-        cmds = [f'mkdir -p {env.gem5_cpdir(self)}']
-        if env.restore_cp and self.modify_checkpoint_tick:
-            cmds.append(
-                f'python3 {env.utilsdir}/modify_gem5_cp_tick.py --tick 0 '
-                f'--cpdir {env.gem5_cpdir(self)}'
-            )
-        return cmds
+        return [f'mkdir -p {env.gem5_cpdir(self)}']
 
     def run_cmd(self, env: ExpEnv) -> str:
         cpu_type = self.cpu_type

experiments/simbricks/utils/__init__.py

-# Copyright 2023 Max Planck Institute for Software Systems, and
-# National University of Singapore
-#
-# Permission is hereby granted, free of charge, to any person obtaining
-# a copy of this software and associated documentation files (the
-# "Software"), to deal in the Software without restriction, including
-# without limitation the rights to use, copy, modify, merge, publish,
-# distribute, sublicense, and/or sell copies of the Software, and to
-# permit persons to whom the Software is furnished to do so, subject to
-# the following conditions:
-#
-# The above copyright notice and this permission notice shall be
-# included in all copies or substantial portions of the Software.
-#
-# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
-# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
-# CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
-# TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
-# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

experiments/simbricks/utils/modify_gem5_cp_tick.py

-# Copyright 2023 Max Planck Institute for Software Systems, and
-# National University of Singapore
-#
-# Permission is hereby granted, free of charge, to any person obtaining
-# a copy of this software and associated documentation files (the
-# "Software"), to deal in the Software without restriction, including
-# without limitation the rights to use, copy, modify, merge, publish,
-# distribute, sublicense, and/or sell copies of the Software, and to
-# permit persons to whom the Software is furnished to do so, subject to
-# the following conditions:
-#
-# The above copyright notice and this permission notice shall be
-# included in all copies or substantial portions of the Software.
-#
-# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
-# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
-# CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
-# TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
-# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-"""Script to modify the tick of a gem5 checkpoint."""
-
-import argparse
-import os
-
-
-def main():
-    parser = argparse.ArgumentParser()
-    parser.add_argument(
-        '--cpdir', help='Path to gem5 checkpoint directory', required=True
-    )
-    parser.add_argument(
-        '--tick',
-        help='The new value for the checkpoint\'s tick',
-        type=int,
-        required=True
-    )
-
-    args = parser.parse_args()
-
-    # Modify tick of all checkpoints in gem5 checkpoint directory to new_tick
-    for cp in filter(
-        lambda file: file.startswith('cpt.'), os.listdir(args.cpdir)
-    ):
-        cp_file = f'{args.cpdir}/{cp}/m5.cpt'
-        if not os.path.exists(cp_file):
-            print(
-                f'WARN {os.path.basename(__file__)}: checkpoint '
-                f'{args.cpdir}/{cp} doesn\'t have a m5.cpt'
-            )
-            continue
-        with open(cp_file, 'r', encoding='utf-8') as f:
-            data: str = f.read()
-        curtick = int(cp.split('.')[1])
-        newdata = data.replace(f'curTick={curtick}', f'curTick={args.tick}', 1)
-        with open(cp_file, 'w', encoding='utf-8') as f:
-            f.write(newdata)
-        print(
-            f'INFO {os.path.basename(__file__)}: successfully set tick of '
-            f'{args.cpdir}/{cp} to {args.tick}'
-        )
-
-
-if __name__ == '__main__':
-    main()