first commit

scripts/python/performance_replay.py

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+#!/usr/bin/env python3
+
+'''
+Replays a Flightgear recording and shows framerate statistics.
+
+Usage:
+    -f <fgfs>
+        Name of Flightear executable/script, e.g.: -f run_fgfs.sh
+    -i <tape>
+        Name of recording, for use with --load-tape.
+'''
+
+import math
+import sys
+import time
+
+import recordreplay
+
+
+def average_stddev(items):
+    '''
+    Returns (average, stddev).
+    '''
+    total = 0
+    total_sq = 0
+    for item in items:
+        total += item
+        total_sq += item*item
+    n = len(items)
+    average = total / n
+    variance = total_sq / n - (total / n)**2
+    stddev = math.sqrt(variance)
+    return average, stddev
+
+
+if __name__ == '__main__':
+    fgfs = None
+    tape = None
+    args = iter(sys.argv[1:])
+    while 1:
+        try:
+            arg = next(args)
+        except StopIteration:
+            break
+        if arg in ('-h', '--help'):
+            print(__doc__)
+        elif arg == '-f':
+            fgfs = next(args)
+        elif arg == '-i':
+            tape = next(args)
+        else:
+            raise Exception(f'Unrecognised arg: {arg}')
+    
+    if not fgfs:
+        raise Exception(f'Specify fgfs executable/run-script with -f')
+    if not tape:
+        raise Exception(f'Specify tape to replay with -i')
+
+    fg = recordreplay.Fg( None,
+            f'{fgfs}'
+                f' --load-tape={tape}'
+                f' --timeofday=noon'
+                f' --prop:bool:/sim/replay/log-frame-times=true'
+                f' --prop:bool:/sim/replay/replay-main-view=true'
+                f' --prop:bool:/sim/replay/replay-main-window-size=true'
+                f' --prop:bool:/sim/replay/looped=false'
+            )
+
+    fg.waitfor('/sim/fdm-initialized', 1, timeout=45)
+    fg.waitfor('/sim/replay/replay-state', 1)
+    fg.waitfor('/sim/replay/replay-state-eof', 1, timeout=600)
+    
+    print(f'Reading frame-time statistics...')
+    t = time.time()
+    items = fg.fg.ls('/sim/replay/log-frame-times')
+    t = time.time() - t
+    print(f'fg.fg.ls took t={t}')
+    
+    fg.close()
+    
+    dts = []
+    for item in items:
+        if item.name == 'dt':
+            dts.append(float(item.value))
+    
+    def statistics_text(dts):
+        dt_average, dt_stddev = average_stddev(dts)
+        t_total = sum(dts)
+        return f'n={len(dts)} dt_average={dt_average} dt_stddev={dt_stddev} t_total={t_total} fps={len(dts)/t_total}'
+    
+    print(f'-' * 40)
+    print(f'')
+    print(f'Overall frame time (dt) statistics:')
+    print(f'    {statistics_text(dts)}')
+    
+    print(f'Ignoring first 4 frames:')
+    print(f'    {statistics_text(dts[4:])}')
+    
+    print(f'')
+    print(f'Raw frame times:')
+    dts_text = ' '.join(map(lambda dt: f'{dt:.4f}', dts))
+    print(f'dts: {dts_text}')