Jeff Epler
a1905b5bfc
this import line was removed without checking, because it caused a pylint message.
67 lines
2.1 KiB
Python
67 lines
2.1 KiB
Python
# SPDX-FileCopyrightText: 2020 Jeff Epler for Adafruit Industries
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#
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# SPDX-License-Identifier: MIT
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import time
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import os
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# pylint: disable=unused-import
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import mount_sd # You must create a module mount_sd.py that mounts your sd card!
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# First, just write the file 'hello.txt' to the card
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with open("/sd/hello.txt", "w") as f:
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print("hello world", file=f)
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print()
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print("SD card I/O benchmarks")
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# Test read and write speed in several scenarios:
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# * 512 or 4096 bytes at a time
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# * Writing 1 time or 16 times
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# First write the content to the SD card, then read it back, reporting the
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# time taken.
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for sz in 512, 4096:
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b = bytearray(sz)
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for i in range(sz):
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b[i] = 0xaa
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for n in (1, 16):
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with open("/sd/hello.bin", "wb") as f:
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t0 = time.monotonic_ns()
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for i in range(n):
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f.write(b)
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t1 = time.monotonic_ns()
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dt = (t1-t0) / 1e9
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print(f"write {len(b)} x {n} in {dt}s {n * len(b) / dt / 1000:.1f}Kb/s")
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with open("/sd/hello.bin", "rb") as f:
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t0 = time.monotonic_ns()
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for i in range(n):
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f.readinto(b)
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t1 = time.monotonic_ns()
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dt = (t1-t0) / 1e9
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print(f"read {len(b)} x {n} in {dt}s {n * len(b) / dt / 1000:.1f}Kb/s")
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print()
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# Test "logging" speed and report the time to write each line.
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# Note that in this test the file is not closed or flushed after each
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# line, so in the event of power loss some lines would be lost. However,
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# it allows much more frequent logging overall.
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#
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# If keeping data integrity is your highest concern, follow the logging
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# example, not this logging benchmark!
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print("logging test")
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with open("/sd/log.txt", "wt") as logfile:
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t0 = time.monotonic_ns()
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for i in range(10000):
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t1 = time.monotonic_ns()
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dt = (t1-t0) / 1e9
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print(f"Line {i}, {dt:2f}s elapsed", file=logfile)
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t1 = time.monotonic_ns()
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dt = (t1-t0) / 1e9
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print(f"Logged 10000 lines in {dt} seconds, {dt*100:.0f}us/line")
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sz = os.stat('/sd/log.txt')[6]
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print(f"{sz} bytes written, {sz/dt/1000:.1f}Kb/s")
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