A quick and dirty script to compare performances between passing an input file as a `file parameter`, as a `redirection` or using an `useless cat`

uuoc-benchmark.sh

DATAFILE="${HOME}/random.data"
SCRIPT="
   {
       /* simulate some processing */
       for(i = 0; i < rand()*1000; ++i)
           acc += i;
   }
"

for n in {00..99}; do
    # Generate few MB of data
    dd if=/dev/urandom of="${DATAFILE}" bs=1M count=500 conv=fdatasync oflag=nocache

    # Drop cache
    dd of="${DATAFILE}" count=0 conv=notrunc,fdatasync oflag=nocache
    echo -e '\nA'
    time \
        awk "${SCRIPT}" "${DATAFILE}"

    # Drop cache
    dd of="${DATAFILE}" count=0 conv=notrunc,fdatasync oflag=nocache
    echo -e '\nB'
    time \
        awk "${SCRIPT}" < "${DATAFILE}"

    # Drop cache
    dd of="${DATAFILE}" count=0 conv=notrunc,fdatasync oflag=nocache
    echo -e '\nC'
    time cat "${DATAFILE}" | \
        awk "${SCRIPT}"
done