Script for randomly writing files to generate work for a cleaner

diff --git a/microbench/cleanbench.py b/microbench/cleanbench.py
new file mode 100755 (executable)
index 0000000..87be6d3
--- /dev/null
+++ b/microbench/cleanbench.py
@@ -0,0 +1,40 @@
+#!/usr/bin/python
+#
+# A workload generator for the cleaner benchmarks.  This will randomly write to
+# a collection of files at a fixed rate, to dirty data in the file system.
+#
+# DO NOT RUN FROM A DIRECTORY WITH FILES YOU CARE ABOUT--it will overwrite
+# files in and under the current directory.
+
+import os, random, sys, time
+
+def write_file(path, size=1024**2):
+    buf = 'A' * size
+    f = open(path, 'w')
+    f.write(buf)
+    f.close()
+
+def modify_files(files, rate=1.0, fraction=0.25):
+    files = random.sample(files, int(round(len(files) * fraction)))
+    print "Modifying", len(files), "files"
+
+    last_time = time.time()
+    latencies = []
+    for f in files:
+        now = time.time()
+        next_time = last_time + (1.0/rate)
+        time.sleep(max(0.0, next_time - now))
+        print "Writing", f
+        write_file(f)
+        last_time = next_time
+    print "Done"
+
+if __name__ == '__main__':
+    print "Modifying files in", os.getcwd()
+    time.sleep(15)
+    all_files = []
+    for (path, dirs, files) in iter(os.walk(".")):
+        for f in files:
+            all_files.append(os.path.join(path, f))
+    print len(all_files), "files total"
+    modify_files(all_files)