boot: script that creates a checkpoint after Linux boot up

This commit is contained in:
Brad Beckmann 2011-02-06 22:14:19 -08:00
parent ebe563e531
commit 3a388aff69

View file

@ -0,0 +1,62 @@
#!/bin/sh
#
# This is a tricky script to understand. When run in M5, it creates
# a checkpoint after Linux boot up, but before any benchmarks have
# been run. By playing around with environment variables, we can
# detect whether the checkpoint has been taken.
# - If the checkpoint hasn't been taken, the script allows M5 to checkpoint the system,
# re-read this script into a new tmp file, and re-run it. On the
# second execution of this script (checkpoint has been taken), the
# environment variable is already set, so the script will exit the
# simulation
# - When we restore the simulation from a checkpoint, we can
# specify a new script for M5 to execute in the full-system simulation,
# and it will be executed as if a checkpoint had just been taken.
#
# Author:
# Joel Hestness, hestness@cs.utexas.edu
# while at AMD Research and Advanced Development Lab
# Date:
# 10/5/2010
#
# Test if the RUNSCRIPT_VAR environment variable is already set
if [ "${RUNSCRIPT_VAR+set}" != set ]
then
# Signal our future self that it's safe to continue
export RUNSCRIPT_VAR=1
else
# We've already executed once, so we should exit
/sbin/m5 exit
fi
# Checkpoint the first execution
echo "Checkpointing simulation..."
/sbin/m5 checkpoint
# Test if we previously okayed ourselves to run this script
if [ "$RUNSCRIPT_VAR" -eq 1 ]
then
# Signal our future self not to recurse infinitely
export RUNSCRIPT_VAR=2
# Read the script for the checkpoint restored execution
echo "Loading new script..."
/sbin/m5 readfile > /tmp/runscript
chmod 755 /tmp/runscript
# Execute the new runscript
if [ -s /tmp/runscript ]
then
exec /tmp/runscript
else
echo "Script not specified. Dropping into shell..."
/bin/bash
fi
fi
echo "Fell through script. Exiting..."
/sbin/m5 exit