[Intel-gfx] [igt-dev] [PATCH i-g-t 3/3] igt/gem_sync: Exercising waiting while keeping the GPU busy

[Antonio Argenziano]

On 10/08/18 04:01, Chris Wilson wrote:
> Normally we wait on the last request, but that overlooks any
> difficulties in waiting on a request while the next is being qeued.

/s/qeued/queued

> Check those.
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> ---
>   tests/gem_sync.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 72 insertions(+)
> 
> diff --git a/tests/gem_sync.c b/tests/gem_sync.c
> index c697220ad..fb209977d 100644
> --- a/tests/gem_sync.c
> +++ b/tests/gem_sync.c
> @@ -294,6 +294,74 @@ wakeup_ring(int fd, unsigned ring, int timeout, int wlen)
>   	igt_assert_eq(intel_detect_and_clear_missed_interrupts(fd), 0);
>   }
>   

> +	intel_detect_and_clear_missed_interrupts(fd);
> +	igt_fork(child, num_engines) {
> +		double start, end, elapsed;
> +		unsigned long cycles;
> +		igt_spin_t *spin[2];
> +		uint32_t cmd;
> +
> +		spin[0] = __igt_spin_batch_new(fd,
> +					       .engine = ring,
> +					       .flags = IGT_SPIN_FAST);
> +		cmd = *spin[0]->batch;
> +
> +		spin[1] = __igt_spin_batch_new(fd,
> +					       .engine = ring,
> +					       .flags = IGT_SPIN_FAST);
> +		igt_assert(*spin[1]->batch == cmd);
> +
> +		start = gettime();
> +		end = start + timeout;
> +		cycles = 0;
> +		do {
> +			for (int loop = 0; loop < 1024; loop++) {
> +				igt_spin_t *s = spin[loop & 1];
> +
> +				igt_spin_batch_end(s);
> +				gem_sync(fd, s->handle);

How does the test fail if the sync goes wrong? Hang detector on the 
queued batch?

Antonio

> +
> +				*s->batch = cmd;
> +				gem_execbuf(fd, &s->execbuf);
> +			}
> +			cycles += 1024;
> +		} while ((elapsed = gettime()) < end);
> +		igt_spin_batch_free(fd, spin[1]);
> +		igt_spin_batch_free(fd, spin[0]);
> +
> +		igt_info("%s%sompleted %ld cycles: %.3f us\n",
> +			 names[child % num_engines] ?: "",
> +			 names[child % num_engines] ? " c" : "C",
> +			 cycles, (elapsed - start)*1e6/cycles);
> +	}
> +	igt_waitchildren_timeout(2*timeout, NULL);
> +	igt_assert_eq(intel_detect_and_clear_missed_interrupts(fd), 0);
> +}
> +