[Intel-gfx] [PATCH i-g-t v6 14/21] tests/sw_sync: Add subtest test_sync_expired_merge

[Chris Wilson]

On Thu, Nov 17, 2016 at 10:02:02AM -0500, robert.foss at collabora.com wrote:
> From: Rafael Antognolli <rafael.antognolli at intel.com>
> 
> This test creates an already expired fence, then creates a merged fence
> out of that expired one (passed twice to the merge operation), and
> finally closes the merged fence. It shows that if the refcounts are
> wrong on the original expired fence, it might get freed while still in
> use. Usually a kernel panick will follow.
> 
> Signed-off-by: Rafael Antognolli <rafael.antognolli at intel.com>
> Signed-off-by: Robert Foss <robert.foss at collabora.com>
> ---
>  tests/sw_sync.c | 28 ++++++++++++++++++++++++++++
>  1 file changed, 28 insertions(+)
> 
> diff --git a/tests/sw_sync.c b/tests/sw_sync.c
> index 4e52f48..65416ad 100644
> --- a/tests/sw_sync.c
> +++ b/tests/sw_sync.c
> @@ -582,6 +582,31 @@ static void test_sync_multi_producer_single_consumer(void)
>  		pthread_join(threads[i], NULL);
>  }
>  
> +static void test_sync_expired_merge(void)
> +{
> +	int iterations = 1 << 20;
> +	int timeline;
> +	int i;
> +	int fence_expired, fence_merged;
> +
> +	timeline = sw_sync_timeline_create();
> +
> +	sw_sync_timeline_inc(timeline, 100);
> +	fence_expired = sw_sync_fence_create(timeline, 1);

igt_assert(sync_wait(fence_expired, 0) == 1);
or
igt_assert(fence_signaled(fence_expired));

Both illustrative of the setup, and tests them.

> +	fence_merged = sync_merge(fence_expired, fence_expired);
> +	close(fence_merged);
> +
> +	for (i = 0; i < iterations; i++) {
> +		int fence = sync_merge(fence_expired, fence_expired);
> +
> +		igt_assert_f(sync_wait(fence, -1) == 0,
> +				     "Failure waiting on fence\n");
> +		close(fence);

Is the millionth iteration more likely to fail than iteration 0?

There's no change in code coverage, so is it worth the extra iterations?
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre