populate: remove file creation loops that take forever

Replace the file creation loops with a perl script that does everything
we want from a single process.  This reduces the runtime of
_scratch_xfs_populate substantially by avoiding thousands of execve
overhead.  On my system, this reduces the runtime of xfs/349 (with scrub
enabled) from ~140s to ~45s.

[zlang: add popdir.pl into src/Makefile install list]

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Zorro Lang <zlang@redhat.com>
Signed-off-by: Zorro Lang <zlang@kernel.org>

2 files changed, 73 insertions, 1 deletions

diff --git a/src/Makefile b/src/Makefile
index afdf6b30..fb7298f8 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -36,7 +36,7 @@ LINUX_TARGETS = xfsctl bstat t_mtab getdevicesize preallo_rw_pattern_reader \
 	uuid_ioctl
 
 EXTRA_EXECS = dmerror fill2attr fill2fs fill2fs_check scaleread.sh \
-	      btrfs_crc32c_forged_name.py
+	      btrfs_crc32c_forged_name.py popdir.pl
 
 SUBDIRS = log-writes perf
 
diff --git a/src/popdir.pl b/src/popdir.pl
new file mode 100755
index 00000000..dc0c046b
--- /dev/null
+++ b/src/popdir.pl
@@ -0,0 +1,72 @@
+#!/usr/bin/perl -w
+
+# Copyright (c) 2023 Oracle.  All rights reserved.
+# SPDX-License-Identifier: GPL-2.0
+#
+# Create a bunch of files and subdirs in a directory.
+
+use Getopt::Long;
+use File::Basename;
+
+$progname=$0;
+GetOptions("start=i" => \$start,
+	   "end=i" => \$end,
+	   "file-mult=i" => \$file_mult,
+	   "incr=i" => \$incr,
+	   "format=s" => \$format,
+	   "dir=s" => \$dir,
+	   "remove!" => \$remove,
+	   "help!" => \$help,
+	   "verbose!" => \$verbose);
+
+
+# check/remove output directory, get filesystem info
+if (defined $help) {
+  # newline at end of die message suppresses line number
+  print STDERR <<"EOF";
+Usage: $progname [options]
+Options:
+  --dir             chdir here before starting
+  --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)
+  --remove          remove instead of creating
+  --format=str      printf formatting string for file name ("%08d")
+  --verbose         verbose output
+  --help            this help screen
+EOF
+  exit(1) unless defined $help;
+  # otherwise...
+  exit(0);
+}
+
+if (defined $dir) {
+	chdir($dir) or die("chdir $dir");
+}
+$start = 0 if (!defined $start);
+$end = 100 if (!defined $end);
+$file_mult = 20 if (!defined $file_mult);
+$format = "%08d" if (!defined $format);
+$incr = 1 if (!defined $incr);
+
+for ($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) {
+		# create a file
+		$verbose && print "touch $fname\n";
+		open(DONTCARE, ">$fname") or die("touch $fname");
+		close(DONTCARE);
+	} else {
+		# create a subdir
+		$verbose && print "mkdir $fname\n";
+		mkdir($fname, 0755) or die("mkdir $fname");
+	}
+}
+
+exit(0);