Test ionice

gistfile1.bash

#!/bin/sh
# This should result in very different completion times for the 2 runs.
# This script is useful to be sure that ionice works on your kernel since it's possible to have the
# ionice command yet using it has no effect
# you can check your scheduler with something like 
# cat /sys/block/sda1/queue/scheduler

# NOTE: I wrote this to help me figure out if ionice was working on my system. It doesn't seem to be, since the
# output of this script indicates that the priorities, while adjusted, don't get reflected in the real world timings.
# I don't know if my script is wrong or if my server is mis-configured.

me=$$
echo "Starting 2 IO ops at different priorities...."
ionice -c2 -n1 bash -c "dd if=/dev/urandom of=ionice-a.log bs=1M count=50 && rm ionice-a.log && echo 'a done'" &
a=$!
ionice -c3 -n1 bash -c "dd if=/dev/urandom of=ionice-b.log bs=1M count=50 && rm ionice-b.log && echo 'b done'" &
b=$!

# let things get forked? sometimes pstree is wrong otherwise
sleep 1

pstree -pal $me

echo "A [`ps --ppid $a -o pid=`]: `ps --ppid $a -o pid= | xargs ionice -p`"
echo "B [`ps --ppid $b -o pid=`]: `ps --ppid $b -o pid= | xargs ionice -p`"