[2/3] populate: create fewer subdirs when constructing directories

Commit Message

Darrick J. Wong April 4, 2023, 11:17 p.m. UTC

From: Darrick J. Wong <[e-mail]>

Based on some surveys of aged filesystems, I've noticed that the
proportion of directory children that are subdirectories tends to be
more in the 5-10% range, not the 95% that the current code generates.
Rework popdir.pl so that we can specify arbitrary percentages of
children files, and lower the ratio dramatically.

This shouldn't have any substantive changes in the shape of the
directories that gets generated; it just gets us a more realistic
sample.

Signed-off-by: Darrick J. Wong <[e-mail]>
---
 common/populate |    4 ++--
 src/popdir.pl   |   15 ++++++++++-----
 2 files changed, 12 insertions(+), 7 deletions(-)

Patch

diff --git a/common/populate b/common/populate
index 144a3f5186..524e0c32cb 100644
--- a/common/populate
+++ b/common/populate
@@ -308,7 +308,7 @@  _scratch_xfs_populate() {
 
 	# Fill up the root inode chunk
 	echo "+ fill root ino chunk"
-	$here/src/popdir.pl --dir "${SCRATCH_MNT}" --start 1 --end 64 --format "dummy%u" --file-mult 1
+	$here/src/popdir.pl --dir "${SCRATCH_MNT}" --start 1 --end 64 --format "dummy%u" --file-pct 100
 
 	# Regular files
 	# - FMT_EXTENTS
@@ -422,7 +422,7 @@  _scratch_xfs_populate() {
 	local rec_per_btblock=16
 	local nr="$(( 2 * (blksz / rec_per_btblock) * ino_per_rec ))"
 	local dir="${SCRATCH_MNT}/INOBT"
-	__populate_create_dir "${dir}" "${nr}" true --file-mult 1
+	__populate_create_dir "${dir}" "${nr}" true --file-pct 100
 
 	# Reverse-mapping btree
 	is_rmapbt="$(_xfs_has_feature "$SCRATCH_MNT" rmapbt -v)"
diff --git a/src/popdir.pl b/src/popdir.pl
index dc0c046b7d..e89095aafe 100755
--- a/src/popdir.pl
+++ b/src/popdir.pl
@@ -11,7 +11,7 @@  use File::Basename;
 $progname=$0;
 GetOptions("start=i" => \$start,
 	   "end=i" => \$end,
-	   "file-mult=i" => \$file_mult,
+	   "file-pct=i" => \$file_pct,
 	   "incr=i" => \$incr,
 	   "format=s" => \$format,
 	   "dir=s" => \$dir,
@@ -30,8 +30,7 @@  Options:
   --start=num       create names starting with this number (0)
   --incr=num        increment file number by this much (1)
   --end=num         stop at this file number (100)
-  --file-mult       create a regular file when file number is a multiple
-                    of this quantity (20)
+  --file-pct        create this percentage of regular files (90 percent)
   --remove          remove instead of creating
   --format=str      printf formatting string for file name ("%08d")
   --verbose         verbose output
@@ -47,17 +46,23 @@  if (defined $dir) {
 }
 $start = 0 if (!defined $start);
 $end = 100 if (!defined $end);
-$file_mult = 20 if (!defined $file_mult);
+$file_pct = 90 if (!defined $file_pct);
 $format = "%08d" if (!defined $format);
 $incr = 1 if (!defined $incr);
 
+if ($file_pct < 0) {
+	$file_pct = 0;
+} elsif ($file_pct > 100) {
+	$file_pct = 100;
+}
+
 for ($i = $start; $i <= $end; $i += $incr) {
 	$fname = sprintf($format, $i);
 
 	if ($remove) {
 		$verbose && print "rm $fname\n";
 		unlink($fname) or rmdir($fname) or die("unlink $fname");
-	} elsif ($file_mult == 0 or ($i % $file_mult) == 0) {
+	} elsif (($i % 100) < $file_pct) {
 		# create a file
 		$verbose && print "touch $fname\n";
 		open(DONTCARE, ">$fname") or die("touch $fname");