diff --git a/d1/f3.sh b/d1/f3.sh
index b37388f..8f489b6 100644
--- a/d1/f3.sh
+++ b/d1/f3.sh
@@ -1,5 +1,6 @@
 $@  'mkdir -p $HOME/p1/p1; mkdir -p $HOME/tmp'
 cat d1/f2.py | $@ sh -c 'cat > $HOME/p1/p1/passenger_wsgi.py'
+cat d1/f4.py | $@ sh -c 'cat > $HOME/p1/p1/f4.py'
 cat tmp/wsgi_config.json | $@ sh -c 'cat > $HOME/p1/p1/wsgi_config.json'
 cat d1/wsgi/.htaccess | $@ sh -c 'cat > $HOME/public_html/.htaccess'
 cat d1/wsgi/busybox | $@ sh -c 'cat > $HOME/tmp/busybox'
diff --git a/d1/f4.py b/d1/f4.py
new file mode 100644
index 0000000..fc34f75
--- /dev/null
+++ b/d1/f4.py
@@ -0,0 +1,73 @@
+import subprocess
+import time
+import os
+import datetime
+import traceback
+import io
+import pprint
+
+def f1():
+    LOG_SIZE = 10 * 1024 * 1024
+    busybox_path = '%s/tmp/busybox' % os.environ['HOME']
+    log_path = '%s/p1/p1/log-f4.txt' % os.environ['HOME']
+    os.makedirs(os.path.dirname(log_path), exist_ok=True)
+
+    def trim_log():
+        if not os.path.exists(log_path):
+            return
+
+        log_size = 0
+
+        try:
+            log_stats = os.stat(log_path)
+            log_size = log_stats.st_size
+        except:
+            return
+
+        if log_size > LOG_SIZE:
+            try:
+                log_path2 = os.path.splitext(log_path)
+                os.rename(
+                    log_path,
+                    '%s-backup%s' % (
+                        log_path2[0],
+                        log_path2[1],
+                    ),
+                )
+            except:
+                return
+
+    def log(data=None):
+        with io.open(log_path, 'a') as f:
+            f.write(
+                '%s\n%s\n%s\n' % (
+                    datetime.datetime.now().isoformat(),
+                    pprint.pformat(data),
+                    traceback.format_exc(),
+                )
+            )
+
+        trim_log()
+
+    while True:
+        try:
+            t1 = subprocess.check_output(
+                [busybox_path, 'ps', '-e', 'cpu']
+            ).decode('utf-8')
+            t2 = t1.splitlines()
+            if len(t2) > 20:
+                log(
+                    dict(t2=t2)
+                )
+                print('\n', end='')
+
+            print('\r%s %d' % (
+                datetime.datetime.now().isoformat(),
+                len(t2),
+            ), end='')
+        except:
+            log()
+        time.sleep(10)
+
+if __name__ == '__main__':
+    f1()