22ba9456de
This patch adds a way to simplify using an external tool to measure timer behaviour on Zephyr. It modifies the timer behaviour jitter_drift.c tests to toggle a GPIO pin (defined via a new DTS compatible, "test-kernel-timer-behavior-external") that can be connected to an external tool, such as a logic analyzer, to measure timer behaviour. This GPIO pin toggle is behind a new CONFIG_TIMER_EXTERNAL_TEST Kconfig. A new pytest test is added so that it can collect the statistics from the external tool and assert some measurements. To collect statistics from the external tool, one needs to provide a Python module which provides a `run(seconds, config)` method, that will perform the test and return the statistics. Check the README file for more information about this interface. Finally, this on twister, this new test is behind a new fixture, "gpio-timerout". Signed-off-by: Ederson de Souza <ederson.desouza@intel.com> Signed-off-by: Tom Burdick <thomas.burdick@intel.com>
78 lines
3.0 KiB
Python
Executable File
78 lines
3.0 KiB
Python
Executable File
# Copyright (c) 2023 Intel Corporation
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#
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# SPDX-License-Identifier: Apache-2.0
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import logging
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from math import ceil
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from twister_harness import DeviceAdapter
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logger = logging.getLogger(__name__)
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def do_analysys(test, stats, config, sys_clock_hw_cycles_per_sec):
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logger.info('====================================================')
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logger.info(f'periodic timer behaviour using {test} mechanism:')
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test_period = int(config['TIMER_TEST_PERIOD'])
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test_samples = int(config['TIMER_TEST_SAMPLES'])
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seconds = (test_period * test_samples) / 1_000_000
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periods_sec = test_period / 1_000_000
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ticks_per_sec = int(config['SYS_CLOCK_TICKS_PER_SEC'])
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periods_tick = ceil(ticks_per_sec * periods_sec)
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expected_period = test_period * sys_clock_hw_cycles_per_sec / 1_000_000
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cyc_per_tick = sys_clock_hw_cycles_per_sec / ticks_per_sec
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expected_period_drift = ((periods_tick * cyc_per_tick - expected_period) /
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sys_clock_hw_cycles_per_sec * 1_000_000)
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expected_total_drift = expected_period_drift * test_samples / 1_000_000
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period_max_drift = (int(config['TIMER_EXTERNAL_TEST_PERIOD_MAX_DRIFT_PPM'])
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/ 1_000_000)
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min_bound = (test_period - period_max_drift * test_period +
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expected_period_drift) / 1_000_000
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max_bound = (test_period + period_max_drift * test_period +
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expected_period_drift) / 1_000_000
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max_stddev = int(config['TIMER_TEST_MAX_STDDEV']) / 1_000_000
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max_drift_ppm = int(config['TIMER_EXTERNAL_TEST_MAX_DRIFT_PPM'])
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time_diff = stats['total_time'] - seconds - expected_total_drift
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logger.info(f'min: {stats["min"] * 1_000_000:.6f} us')
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logger.info(f'max: {stats["max"] * 1_000_000:.6f} us')
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logger.info(f'mean: {stats["mean"] * 1_000_000:.6f} us')
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logger.info(f'variance: {stats["var"] * 1_000_000:.6f} us')
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logger.info(f'stddev: {stats["stddev"] * 1_000_000:.6f} us')
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logger.info(f'total time: {stats["total_time"] * 1_000_000:.6f} us')
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logger.info(f'expected drift: {seconds * max_drift_ppm} us')
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logger.info(f'real drift: {time_diff * 1_000_000:.6f} us')
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logger.info('====================================================')
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assert stats['stddev'] < max_stddev
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assert stats['min'] >= min_bound
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assert stats['max'] <= max_bound
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assert abs(time_diff) < seconds * max_drift_ppm / 1_000_000
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def wait_sync_point(dut: DeviceAdapter, point):
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dut.readlines_until(regex=f"===== {point} =====")
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def test_flash(dut: DeviceAdapter, tool, tool_options, config,
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sys_clock_hw_cycles_per_sec):
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tool = __import__(tool)
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test_period = int(config['TIMER_TEST_PERIOD'])
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test_samples = int(config['TIMER_TEST_SAMPLES'])
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seconds = (test_period * test_samples) / 1_000_000
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tests = ["builtin", "startdelay"]
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for test in tests:
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wait_sync_point(dut, test)
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stats = tool.run(seconds, tool_options)
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do_analysys(test, stats, config, sys_clock_hw_cycles_per_sec)
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