1  # SPDX-FileCopyrightText: 2020 Jeff Epler for Adafruit Industries
 2  #
 3  # SPDX-License-Identifier: MIT
 4  
 5  import time
 6  import os
 7  
 8  
 9  # First, just write the file 'hello.txt' to the card
10  with open("/sd/hello.txt", "w") as f:
11      print("hello world", file=f)
12  
13  print()
14  print("SD card I/O benchmarks")
15  
16  # Test read and write speed in several scenarios:
17  #  * 512 or 4096 bytes at a time
18  #  * Writing 1 time or 16 times
19  # First write the content to the SD card, then read it back, reporting the
20  # time taken.
21  for sz in 512, 4096:
22      b = bytearray(sz)
23      for i in range(sz):
24          b[i] = 0xaa
25      for n in (1, 16):
26          with open("/sd/hello.bin", "wb") as f:
27              t0 = time.monotonic_ns()
28              for i in range(n):
29                  f.write(b)
30              t1 = time.monotonic_ns()
31  
32          dt = (t1-t0) / 1e9
33          print(f"write {len(b)} x {n} in {dt}s {n * len(b) / dt / 1000:.1f}Kb/s")
34  
35          with open("/sd/hello.bin", "rb") as f:
36              t0 = time.monotonic_ns()
37              for i in range(n):
38                  f.readinto(b)
39              t1 = time.monotonic_ns()
40  
41          dt = (t1-t0) / 1e9
42  
43          print(f"read  {len(b)} x {n} in {dt}s {n * len(b) / dt / 1000:.1f}Kb/s")
44          print()
45  
46  # Test "logging" speed and report the time to write each line.
47  # Note that in this test the file is not closed or flushed after each
48  # line, so in the event of power loss some lines would be lost.  However,
49  # it allows much more frequent logging overall.
50  #
51  # If keeping data integrity is your highest concern, follow the logging
52  # example, not this logging benchmark!
53  print("logging test")
54  with open("/sd/log.txt", "wt") as logfile:
55      t0 = time.monotonic_ns()
56      for i in range(10000):
57          t1 = time.monotonic_ns()
58          dt = (t1-t0) / 1e9
59          print(f"Line {i}, {dt:2f}s elapsed", file=logfile)
60  t1 = time.monotonic_ns()
61  dt = (t1-t0) / 1e9
62  
63  print(f"Logged 10000 lines in {dt} seconds, {dt*100:.0f}us/line")
64  sz = os.stat('/sd/log.txt')[6]
65  print(f"{sz} bytes written, {sz/dt/1000:.1f}Kb/s")