1 files changed, 27 insertions, 0 deletions
diff --git a/research/experiments/029-across-machines/clock.py b/research/experiments/029-across-machines/clock.py
new file mode 100644
index 0000000..f65a21a
--- /dev/null
+++ b/research/experiments/029-across-machines/clock.py
@@ -0,0 +1,27 @@
+#!/usr/bin/env python3
+"""Whether this machine's wall clock jumps (research 029): the wall clock
+(time.time) against the monotonic one, read every 20 ms for SECONDS; each
+step where the wall clock moved more than 20 ms apart from the monotonic
+one, how far, and when (also on the system's monotonic clock). A JSON line
+each, then one with the totals.
+
+clock.py SECONDS"""
+import json
+import sys
+import time
+
+seconds = float(sys.argv[1])
+start_wall, start_mono = time.time(), time.monotonic()
+wall, mono, jumps = start_wall, start_mono, 0
+while mono - start_mono < seconds:
+    time.sleep(0.02)
+    now_wall, now_mono = time.time(), time.monotonic()
+    apart = (now_wall - wall) - (now_mono - mono)
+    if abs(apart) > 0.02:
+        jumps += 1
+        print(json.dumps({'at_s': round(now_mono - start_mono, 2), 'monotonic': round(now_mono, 2),
+                          'wall_moved_ms': round((now_wall - wall) * 1000, 1),
+                          'monotonic_moved_ms': round((now_mono - mono) * 1000, 1)}), flush=True)
+    wall, mono = now_wall, now_mono
+drift = (time.time() - start_wall) - (time.monotonic() - start_mono)
+print(json.dumps({'seconds': seconds, 'jumps': jumps, 'wall_minus_monotonic_ms': round(drift * 1000, 1)}))