Currently, we use "ls ... | sort -R | head -n1" to choose a removing victim. It sorts the files with "ls", sort it randomly and pick the first line, which wastes the "ls" sort. Also, using "sort -R | head -n1" is inefficient. For example, in a directory with 1000000 files, it takes more than 15 seconds to pick a file. $ time bash -c "ls -U | sort -R | head -n 1 >/dev/null" bash -c "ls -U | sort -R | head -n 1 >/dev/null" 15.38s user 0.14s system 99% cpu 15.536 total $ time bash -c "ls -U | shuf -n 1 >/dev/null" bash -c "ls -U | shuf -n 1 >/dev/null" 0.30s user 0.12s system 138% cpu 0.306 total So, just use "ls -U" and "shuf -n 1" to choose a victim. Signed-off-by: Naohiro Aota <naohiro.aota@xxxxxxx> --- tests/btrfs/179 | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tests/btrfs/179 b/tests/btrfs/179 index 2f17c9f9fb4a..0fbd875cf01b 100755 --- a/tests/btrfs/179 +++ b/tests/btrfs/179 @@ -45,7 +45,7 @@ fill_workload() # Randomly remove some files for every 5 loop if [ $(( $i % 5 )) -eq 0 ]; then - victim=$(ls "$SCRATCH_MNT/src" | sort -R | head -n1) + victim=$(ls -U "$SCRATCH_MNT/src" | shuf -n 1) rm "$SCRATCH_MNT/src/$victim" fi i=$((i + 1)) -- 2.41.0
