Re: [igt-dev] [PATCH i-g-t v3 2/2] amdgpu/info: add timestamp-related tests

[Petri Latvala <petri.latvala@intel.com>]

On Tue, Feb 16, 2021 at 10:25:57PM +0200, Martin Peres wrote:
> This test makes sure:
> 
>  * the clock is running at the expected rate
>  * (potential) power gating has no effect on the clock
> 
> v2:
>  - use signed integer for the gpu timestamp diff (Bas)
> 
> v3:
>  - add test and subtest descriptions (Arek)
>  - split the fast and long tests in different subtests (Martin)
>  - use igt_stats to compute actual statistics (Chris)
> 
> v4:
>  - call igt_stats_fini() after finishing with the stats (Petri)
> 
> Cc: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
> Signed-off-by: Martin Peres <martin.peres@mupuf.org>

I have no way of assessing the coverage of the test etc so I'll just
provide drive-by cosmetic suggestions below.


> ---
>  tests/amdgpu/amd_info.c | 79 +++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 79 insertions(+)
> 
> diff --git a/tests/amdgpu/amd_info.c b/tests/amdgpu/amd_info.c
> index 6764e640..e3b1eac1 100644
> --- a/tests/amdgpu/amd_info.c
> +++ b/tests/amdgpu/amd_info.c
> @@ -44,6 +44,75 @@ static void query_firmware_version_test(void)
>  	igt_assert_eq(r, 0);
>  }
>  
> +static void query_timestamp_test(uint32_t sleep_time, int sample_count)
> +{
> +	struct amdgpu_gpu_info gpu_info = {};
> +	double median, std_err, err_95_conf;
> +	igt_stats_t stats;
> +	float ns_per_tick;
> +	int i;
> +
> +	igt_stats_init_with_size(&stats, sample_count);
> +
> +	/* figure out how many nanoseconds each gpu timestamp tick represents */
> +	igt_assert_eq(amdgpu_query_gpu_info(dev, &gpu_info), 0);
> +	igt_assert_lt(0, gpu_info.gpu_counter_freq);

Consider whether you want to say "timestamp querying is broken" or
"cannot test timestamp querying" with these, aka igt_assert vs
igt_require.


> +	ns_per_tick = 1e9 / (gpu_info.gpu_counter_freq * 1000.0);
> +
> +	/* acquire the data needed for the analysis */
> +	for (i = 0; i < sample_count; i++) {
> +		uint64_t ts_start, ts_end, cpu_delta;
> +		int64_t gpu_delta;
> +		float corrected_gpu_delta;
> +		struct timespec ts_cpu;
> +		int r;
> +
> +		igt_assert_eq(igt_gettime(&ts_cpu), 0);
> +
> +		r = amdgpu_query_info(dev, AMDGPU_INFO_TIMESTAMP, 8, &ts_start);
> +		igt_assert_eq(r, 0);
> +
> +		usleep(sleep_time);
> +
> +		r = amdgpu_query_info(dev, AMDGPU_INFO_TIMESTAMP, 8, &ts_end);
> +		igt_assert_eq(r, 0);

Both of these query_info return value checks, when failing, will just
say "test failed, r is not 0". Consider igt_assert_f with a message
that states what is broken.


-- 
Petri Latvala
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