btrfs-benchmark.sh

# !/bin/sh
set -e

# $HOME is on a ext4 filesystem
BENCHMARK_DIR=/tmp/silesia
N=10

# Create the BtrFS filesystem
rm -f /tmp/disk
losetup -D
umount /mnt/test ||:
dd if=/dev/zero of=/tmp/disk bs=4096 seek=1048575 count=1
mkfs.btrfs -msingle /tmp/disk
losetup -f /tmp/disk
sleep 1 # yay udev races
# Mount the filesystem
mount -onoatime,compress-force=$1 /dev/loop0 /mnt/test

echo "Benchmarking $1"
# Run the benchmark
echo "Compression"
time sh -c "for i in \$(seq $N); do cp -r $BENCHMARK_DIR /mnt/test/\$i; done; sync"

# Unmount and remount to avoid any caching
umount /mnt/test
losetup -D
losetup -f /tmp/disk
mount -onoatime,compress=$1 /dev/loop0 /mnt/test

echo "Approximate compression ratio"
# Should probably switch to compsize
printf "%d / %d\n"                                                             \
  $(df /mnt/test --output=used -B 1 | tail -n 1)                               \
  $(du /mnt/test -b -d 0 | tr '\t' '\n' | head -n 1);

# Unmount and remount to avoid any caching
umount /mnt/test
losetup -D
losetup -f /tmp/disk
mount -onoatime,compress-force=$1 /dev/loop0 /mnt/test

echo "Decompression"
time tar -c /mnt/test | wc -c

# Cleanup
losetup -D
umount /mnt/test
rm -f /tmp/disk