#! /bin/zsh

# here are some useful zsh commands
# that will facilitate running experiments
# using the system described in this report

# misc
now-ns    () { echo $((`date +%s`*10**9 + `date +%N`)) }
get-group () { awk '{print $5}' < /proc/$1/stat        }

# this is cgroup 0
# a cgroup is a set of processes
# that can be stopped and resumed collectively
BE_PATH=/sys/fs/cgroup/freezer/0   # the cgroup path
STATE_FILE=$BE_PATH/freezer.state  # and state: either FROZEN or THAWED
TASK_FILE=$BE_PATH/tasks           # PIDs of processes included

# if cgroup 0 has not been created, use this to create it:
# the permissions are set so that you don't need root
# either to add/remove a process to the group,
# nor to have it stopped or resumed
be-init () {
    if [[ ! -d $BE_PATH ]]; then
       su -c "mkdir $BE_PATH; chmod a=wr $STATE_FILE $TASK_FILE"
    fi
    be-start
}

# manually set the state of the cgroup:
# normally, this will not be done
# but for debugging
be-stop  () { echo FROZEN > $STATE_FILE }
be-start () { echo THAWED > $STATE_FILE }

# this runs a program on BE, and
# adds the PID to the cgroup
be-task () {
    taskset -c $BE_CORE $@ &
    local pid=$!
    echo $pid >> $TASK_FILE
}

# play a multimedia file with mplayer2(1) on BE
be-mp () {
    be-task mplayer --ao=null --loop=0 -noconsolecontrols -fs \
            $1 &> /dev/null
}

# memory stress(1) with N spinners of malloc(3)/free(3)
# on either core
cc-stress      () { stress --vm $1 -t 60 }
cont-be-stress () { while (true) { be-stress 10 10 } }
be-stress () {
    local amp=$1
    local time=$2
    local  io=$((4*$amp))
    local  vm=$((2*$amp))
    local vmb=$((128*2**((log($amp)/log(2)))))M
    be-task stress --io $io         \
                   --vm $vm         \
                   --vm-bytes $vmb  \
                   --timeout $time  > /dev/null
}

be-movie () { be-mp ~/box/GGG_Rubio.mp4 }

be-kill () { killall -9 $@ 2> /dev/null }