Commit 699785f5 authored by Daniel Lezcano's avatar Daniel Lezcano Committed by Thomas Gleixner
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genirq/timings: Add selftest for next event computation 



The circular buffers are now validated with selftests. The next interrupt
index algorithm which is the hardest part to validate needs extra coverage.

Add a selftest which uses the intervals stored in the arrays and insert all
the values except the last one. The next event computation must return the
same value as the last element which was not inserted.

Signed-off-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: andriy.shevchenko@linux.intel.com
Link: https://lkml.kernel.org/r/20190527205521.12091-9-daniel.lezcano@linaro.org
parent f52da98d

kernel/irq/timings.c

+66 −0
Original line number Diff line number Diff line
@@ -704,6 +704,68 @@ static struct timings_intervals tis[] __initdata = { 
	{ intervals4, ARRAY_SIZE(intervals4) },

};



static int __init irq_timings_test_next_index(struct timings_intervals *ti)

{

	int _buffer[IRQ_TIMINGS_SIZE];

	int buffer[IRQ_TIMINGS_SIZE];

	int index, start, i, count, period_max;



	count = ti->count - 1;



	period_max = count > (3 * PREDICTION_PERIOD_MAX) ?

		PREDICTION_PERIOD_MAX : count / 3;



	/*

	 * Inject all values except the last one which will be used

	 * to compare with the next index result.

	 */

	pr_debug("index suite: ");



	for (i = 0; i < count; i++) {

		index = irq_timings_interval_index(ti->intervals[i]);

		_buffer[i & IRQ_TIMINGS_MASK] = index;

		pr_cont("%d ", index);

	}



	start = count < IRQ_TIMINGS_SIZE ? 0 :

		count & IRQ_TIMINGS_MASK;



	count = min_t(int, count, IRQ_TIMINGS_SIZE);



	for (i = 0; i < count; i++) {

		int index = (start + i) & IRQ_TIMINGS_MASK;

		buffer[i] = _buffer[index];

	}



	index = irq_timings_next_event_index(buffer, count, period_max);

	i = irq_timings_interval_index(ti->intervals[ti->count - 1]);



	if (index != i) {

		pr_err("Expected (%d) and computed (%d) next indexes differ\n",

		       i, index);

		return -EINVAL;

	}



	return 0;

}



static int __init irq_timings_next_index_selftest(void)

{

	int i, ret;



	for (i = 0; i < ARRAY_SIZE(tis); i++) {



		pr_info("---> Injecting intervals number #%d (count=%zd)\n",

			i, tis[i].count);



		ret = irq_timings_test_next_index(&tis[i]);

		if (ret)

			break;

	}



	return ret;

}



static int __init irq_timings_test_irqs(struct timings_intervals *ti)

{

	struct irqt_stat __percpu *s;
@@ -875,6 +937,10 @@ static int __init irq_timings_selftest(void) 
		goto out;



	ret = irq_timings_irqs_selftest();

	if (ret)

		goto out;



	ret = irq_timings_next_index_selftest();

out:

	pr_info("---------- selftest end with %s -----------\n",

		ret ? "failure" : "success");

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