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isolate/isolate-check-environment
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| r256 | #!/bin/sh | |||
| # | ||||
| # Identifies potential sources issues when using isolate. | ||||
| # | ||||
| # (c) 2017 Bernard Blackham <bernard@blackham.com.au> | ||||
| # | ||||
| usage() { | ||||
| cat <<EOT >&2 | ||||
| Usage: $0 [-q|--quiet] [-e|--execute] | ||||
| Use this script to identify sources of run-time variability and other issues on | ||||
| Linux machines which may affect isolate. If --execute is not specified, the | ||||
| recommended actions are written to stdout as an executable shell script, | ||||
| otherwise, using --execute will attempt to make changes to make the system | ||||
| behave more deterministically. The changes performed by --execute persist only | ||||
| until a reboot. To persist across reboots, the standard output from this script | ||||
| should be added to /etc/rc.local or some other script that is run on each boot. | ||||
| Alternately, you could add the following line to /etc/rc.local to automatically | ||||
| apply these changes on boot, but use this with caution as not all issues can | ||||
| be resolved in this way. | ||||
| isolate-check-environment --quiet --execute | ||||
| The exit status of this script will be 0 if all checks pass, or 1 if some | ||||
| checks have failed. | ||||
| Note that there are more strategies to reduce run-time variability further. | ||||
| See the man page of isolate for details under REPRODUCIBILITY. | ||||
| EOT | ||||
| exit 2 | ||||
| } | ||||
| # Parse options. | ||||
| args=$(getopt -o "ehq" --long "execute,help,quiet" -- "$@") || usage | ||||
| eval set -- "$args" | ||||
| quiet= | ||||
| execute= | ||||
| while : ; do | ||||
| case "$1" in | ||||
| -q|--quiet) quiet=1 ; shift ;; | ||||
| -e|--execute) execute=1 ; shift ;; | ||||
| -h|--help) usage ;; | ||||
| --) shift ; break ;; | ||||
| *) usage ;; | ||||
| esac | ||||
| done | ||||
| [ -n "$*" ] && usage | ||||
| # Some helper boilerplate machinery. | ||||
| exit_status=0 | ||||
| red=$(tput setaf 1) | ||||
| green=$(tput setaf 2) | ||||
| yellow=$(tput setaf 3) | ||||
| normal=$(tput sgr0) | ||||
| # Return true (0) if we are being quiet. | ||||
| quiet() { | ||||
| [ -n "$quiet" ] | ||||
| } | ||||
| # Print all arguments to stderr as warning. | ||||
| warn() { | ||||
| quiet || echo WARNING: "$*" >&2 | ||||
| } | ||||
| # Print first argument to stderr as warning, and second argument to stdout as | ||||
| # the recommended remedial action, or execute if --execute is given. | ||||
| action() { | ||||
| quiet || warn "$1" | ||||
| if [ -n "$execute" ] ; then | ||||
| quiet || echo "+ $2" | ||||
| sh -c "$2" | ||||
| else | ||||
| quiet || echo $2 | ||||
| fi | ||||
| } | ||||
| print_start_check() { | ||||
| quiet && return | ||||
| print_check_status=1 | ||||
| echo -n "Checking for $@ ... " >&2 | ||||
| } | ||||
| print_fail() { | ||||
| exit_status=1 | ||||
| quiet && return | ||||
| [ -n "$print_check_status" ] && echo "${red}FAIL${normal}" >&2 | ||||
| print_check_status= | ||||
| } | ||||
| print_dubious() { | ||||
| exit_status=1 | ||||
| quiet && return | ||||
| [ -n "$print_check_status" ] && echo "${yellow}CAUTION${normal}" >&2 | ||||
| print_check_status= | ||||
| } | ||||
| print_skipped() { | ||||
| quiet && return | ||||
| [ -n "$print_check_status" ] && echo "SKIPPED (not detected)" >&2 | ||||
| print_check_status= | ||||
| } | ||||
| print_finish() { | ||||
| quiet && return | ||||
| [ -n "$print_check_status" ] && echo "${green}PASS${normal}" >&2 | ||||
| print_check_status= | ||||
| } | ||||
| # Check that cgroups are enabled. | ||||
| cgroup_check() { | ||||
| local cgroup=$1 | ||||
| print_start_check "cgroup support for $cgroup" | ||||
| if ! test -f "/sys/fs/cgroup/$cgroup/tasks" ; then | ||||
| print_dubious | ||||
| warn "the $cgroup is not present. isolate --cg cannot be used." | ||||
| fi | ||||
| print_finish | ||||
| } | ||||
| cgroup_check memory | ||||
| cgroup_check cpuacct | ||||
| cgroup_check cpuset | ||||
| # Check that swap is either disabled or accounted for. | ||||
| swap_check() { | ||||
| print_start_check "swap" | ||||
| # If swap is disabled, there is nothing to worry about. | ||||
| local swaps | ||||
| swaps=$(swapon --noheadings) | ||||
| if [ -n "$swaps" ] ; then | ||||
| # Swap is enabled. We had better have the memsw support in the memory | ||||
| # cgroup. | ||||
| if ! test -f "/sys/fs/cgroup/memory/memory.memsw.usage_in_bytes" ; then | ||||
| print_fail | ||||
| action \ | ||||
| "swap is enabled, but swap accounting is not. isolate will not be able to enforce memory limits." \ | ||||
| "swapoff -a" | ||||
| else | ||||
| print_dubious | ||||
| warn "swap is enabled, and although accounted for, may still give run-time variability under memory pressure." | ||||
| fi | ||||
| fi | ||||
| print_finish | ||||
| } | ||||
| swap_check | ||||
| # Check that CPU frequency scaling is disabled. | ||||
| cpufreq_check() { | ||||
| print_start_check "CPU frequency scaling" | ||||
| local anycpus policy | ||||
| anycpus= | ||||
| # Ensure cpufreq governor is set to performance on all CPUs | ||||
| for cpufreq_file in $(find /sys/devices/system/cpu/cpufreq/ -name scaling_governor) ; do | ||||
| policy=$(cat $cpufreq_file) | ||||
| if [ "$policy" != "performance" ] ; then | ||||
| print_fail | ||||
| action \ | ||||
| "cpufreq governor set to '$policy', but 'performance' would be better" \ | ||||
| "echo performance > $cpufreq_file" | ||||
| fi | ||||
| anycpus=1 | ||||
| done | ||||
| [ -z "$anycpus" ] && print_skipped | ||||
| print_finish | ||||
| } | ||||
| cpufreq_check | ||||
| # Check that address space layout randomisation is disabled. | ||||
| aslr_check() { | ||||
| print_start_check "kernel address space randomisation" | ||||
| local val | ||||
| if val=$(cat /proc/sys/kernel/randomize_va_space 2>/dev/null) ; then | ||||
| if [ "$val" -ne 0 ] ; then | ||||
| print_fail | ||||
| action \ | ||||
| "address space randomisation is enabled." \ | ||||
| "echo 0 > /proc/sys/kernel/randomize_va_space" | ||||
| fi | ||||
| else | ||||
| print_skipped | ||||
| fi | ||||
| print_finish | ||||
| } | ||||
| aslr_check | ||||
| # Check that transparent huge-pages are disabled, as this leads to | ||||
| # non-determinism depending on whether the kernel can allocate 2 MiB pages or | ||||
| # not. | ||||
| thp_check() { | ||||
| print_start_check "transparent hugepage support" | ||||
| local val | ||||
| if val=$(cat /sys/kernel/mm/transparent_hugepage/enabled 2>/dev/null) ; then | ||||
| case $val in | ||||
| *'[never]'*) ;; | ||||
| *) print_fail | ||||
| action \ | ||||
| "transparent hugepages are enabled." \ | ||||
| "echo never > /sys/kernel/mm/transparent_hugepage/enabled" ;; | ||||
| esac | ||||
| fi | ||||
| if val=$(cat /sys/kernel/mm/transparent_hugepage/defrag 2>/dev/null) ; then | ||||
| case $val in | ||||
| *'[never]'*) ;; | ||||
| *) print_fail | ||||
| action \ | ||||
| "transparent hugepage defrag is enabled." \ | ||||
| "echo never > /sys/kernel/mm/transparent_hugepage/defrag" ;; | ||||
| esac | ||||
| fi | ||||
| if val=$(cat /sys/kernel/mm/transparent_hugepage/khugepaged/defrag 2>/dev/null) ; then | ||||
| if [ "$val" -ne 0 ] ; then | ||||
| print_fail | ||||
| action \ | ||||
| "khugepaged defrag is enabled." \ | ||||
| "echo 0 > /sys/kernel/mm/transparent_hugepage/khugepaged/defrag" | ||||
| fi | ||||
| fi | ||||
| print_finish | ||||
| } | ||||
| thp_check | ||||
| exit $exit_status | ||||