diff --git a/rootfs_size/rootfs_size.py b/rootfs_size/rootfs_size.py
index cfacb02..3e21b78 100755
--- a/rootfs_size/rootfs_size.py
+++ b/rootfs_size/rootfs_size.py
@@ -5,6 +5,9 @@
 import os
 from os.path import join, getsize
 import argparse
+from multiprocessing import Pool, cpu_count
+import shutil
+import sys
 
 # Set command line arguments
 parser = argparse.ArgumentParser(
@@ -21,55 +24,71 @@
                     "/intel-platforms-wolfpass.squashfs-xz",
                     help="Squashfs file.")
 
+parser.add_argument("-t", "--threads",
+                    dest="threads",
+                    default=int(cpu_count()),
+                    type=int,
+                    help="Number of threads to use (defaults to cpu count)")
+
 args = parser.parse_args()
 
 # files below this size wont be attempted
 FILE_SIZE_LIMIT = 0
 
-SQUASHFS = args.BUILD_DIR + args.SQUASHFS_FILE
+SQUASHFS = args.SQUASHFS_FILE
+if not os.path.isabs(args.SQUASHFS_FILE):
+    SQUASHFS = args.BUILD_DIR + args.SQUASHFS_FILE
 
 original_size = getsize(SQUASHFS)
 print("squashfs size: {}".format(original_size))
 
 results = []
 
-with tempfile.TemporaryDirectory() as tempremovedfile:
-    with tempfile.TemporaryDirectory() as tempsquashfsdir:
-        print("writing to " + tempsquashfsdir)
-        command = ["unsquashfs", "-d",
-                   os.path.join(tempsquashfsdir, "squashfs-root"),  SQUASHFS]
-        print(" ".join(command))
-        subprocess.check_call(command)
-        squashfsdir = tempsquashfsdir + "/squashfs-root"
 
-        files_to_test = []
-        for root, dirs, files in os.walk(squashfsdir):
-            for name in files + dirs:
-                filepath = os.path.join(root, name)
-                if not os.path.islink(filepath):
-                    # ensure files/dirs can be renamed
-                    os.chmod(filepath, 0o711)
-                    if getsize(filepath) > FILE_SIZE_LIMIT:
-                        files_to_test.append(filepath)
+def get_unsquash_results(filepath):
+    with tempfile.TemporaryDirectory() as newsquashfsroot:
+        input_path = os.path.join(newsquashfsroot, "input")
+        shutil.copytree(squashfsdir, input_path, symlinks=True,
+                        ignore_dangling_symlinks=True)
+        file_to_remove = os.path.join(input_path, filepath)
+        try:
+            os.remove(file_to_remove)
+        except IsADirectoryError:
+            shutil.rmtree(file_to_remove)
+        subprocess.check_output(
+            ["mksquashfs", input_path,
+             newsquashfsroot + "/test", "-comp", "xz", '-processors', '1'])
 
-        print("{} files to attempt removing".format(len(files_to_test)))
+        return ((filepath.replace(squashfsdir, ""),
+                 original_size -
+                 getsize(newsquashfsroot + "/test")))
 
-        for filepath in files_to_test:
-            name = os.path.basename(filepath)
-            newname = os.path.join(tempremovedfile, name)
-            os.rename(filepath, newname)
-            with tempfile.TemporaryDirectory() as newsquashfsroot:
-                subprocess.check_output(
-                    ["mksquashfs", tempsquashfsdir,
-                     newsquashfsroot + "/test", "-comp", "xz"])
 
-                results.append((filepath.replace(squashfsdir, ""),
-                                original_size -
-                                getsize(newsquashfsroot + "/test")))
+with tempfile.TemporaryDirectory() as tempsquashfsdir:
+    print("writing to " + tempsquashfsdir)
+    squashfsdir = os.path.join(tempsquashfsdir, "squashfs-root")
+    #squashfsdir = os.path.join("/tmp", "squashfs-root")
+    command = ["unsquashfs", "-d", squashfsdir, SQUASHFS]
+    print(" ".join(command))
+    subprocess.check_call(command)
 
-            os.rename(newname, filepath)
+    files_to_test = []
+    for root, dirs, files in os.walk(squashfsdir):
+        for name in files + dirs:
+            filepath = os.path.join(root, name)
+            if not os.path.islink(filepath):
+                if getsize(filepath) > FILE_SIZE_LIMIT:
+                    files_to_test.append(
+                        os.path.relpath(filepath, squashfsdir))
 
-            print("{:>6} of {}".format(len(results), len(files_to_test)))
+    print("{} files to attempt removing".format(len(files_to_test)))
+
+    print("Using {} threads".format(args.threads))
+    with Pool(args.threads) as p:
+        for i, res in enumerate(p.imap_unordered(get_unsquash_results, files_to_test)):
+            results.append(res)
+            sys.stderr.write('\rdone {:.1f}%'.format(
+                100 * (i/len(files_to_test))))
 
 results.sort(key=lambda x: x[1], reverse=True)