diff mbox series

[v3,3/3] btrfs/004: use shuf to shuffle the file lines

Message ID 2d118ed03559472a0bf878509a32a9dded03efb2.1692600259.git.naohiro.aota@wdc.com (mailing list archive)
State New, archived
Headers show
Series use shuf to choose a random file | expand

Commit Message

Naohiro Aota Aug. 21, 2023, 7:12 a.m. UTC
The "sort -R" is slower than "shuf" even with the full output because
"sort -R" actually sort them to group the identical keys.

  $ time bash -c "seq 1000000 | shuf >/dev/null"
  bash -c "seq 1000000 | shuf >/dev/null"  0.18s user 0.03s system 104% cpu 0.196 total

  $ time bash -c "seq 1000000 | sort -R >/dev/null"
  bash -c "seq 1000000 | sort -R >/dev/null"  19.61s user 0.03s system 99% cpu 19.739 total

Since the "find"'s outputs never be identical, we can just use "shuf" to
optimize the selection.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 tests/btrfs/004 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Anand Jain Aug. 21, 2023, 9:25 a.m. UTC | #1
LGTM

Reviewed-by: Anand Jain <anand.jain@oracle.com>
diff mbox series

Patch

diff --git a/tests/btrfs/004 b/tests/btrfs/004
index ea40dbf62880..78df6a3af6b1 100755
--- a/tests/btrfs/004
+++ b/tests/btrfs/004
@@ -201,7 +201,7 @@  workout()
 	cnt=0
 	errcnt=0
 	dir="$SCRATCH_MNT/$snap_name/"
-	for file in `find $dir -name f\* -size +0 | sort -R`; do
+	for file in `find $dir -name f\* -size +0 | shuf`; do
 		extents=`_check_file_extents $file`
 		ret=$?
 		if [ $ret -ne 0 ]; then