[RFC PATCH 1/1] drm/mm: add ig_frag selftest

[Nirmoy]

This works correctly most of the times but sometimes

20k insertions can take more than 8 times of 10k insertion time.


Regards,

Nirmoy

On 5/29/20 6:33 PM, Nirmoy Das wrote:
> This patch introduces fragmentation in the address range
> and measures time taken by 10k and 20k insertions. ig_frag()
> will fail if time taken by 20k insertions takes more than 4 times
> of 10k insertions as we know that insertions scale quadratically.
> Also tolerate 10% error because of kernel scheduler's jitters.
>
> Output:
> <snip>
> [ 8092.653518] drm_mm: Testing DRM range manger (struct drm_mm), with random_seed=0x9bfb4117 max_iterations=8192 max_prime=128
> [ 8092.653520] drm_mm: igt_sanitycheck - ok!
> [ 8092.653525] igt_debug 0x0000000000000000-0x0000000000000200: 512: free
> [ 8092.653526] igt_debug 0x0000000000000200-0x0000000000000600: 1024: used
> [ 8092.653527] igt_debug 0x0000000000000600-0x0000000000000a00: 1024: free
> [ 8092.653528] igt_debug 0x0000000000000a00-0x0000000000000e00: 1024: used
> [ 8092.653529] igt_debug 0x0000000000000e00-0x0000000000001000: 512: free
> [ 8092.653529] igt_debug total: 4096, used 2048 free 2048
> [ 8112.569813] drm_mm: best fragmented insert of 10000 and 20000 insertions took 504 and 1996 msecs
> [ 8112.723254] drm_mm: bottom-up fragmented insert of 10000 and 20000 insertions took 44 and 108 msecs
> [ 8112.813212] drm_mm: top-down fragmented insert of 10000 and 20000 insertions took 40 and 44 msecs
> [ 8112.847733] drm_mm: evict fragmented insert of 10000 and 20000 insertions took 8 and 20 msecs
> <snip>
>
> Signed-off-by: Nirmoy Das <nirmoy.das at amd.com>
> ---
>   drivers/gpu/drm/selftests/drm_mm_selftests.h |  1 +
>   drivers/gpu/drm/selftests/test-drm_mm.c      | 73 ++++++++++++++++++++
>   2 files changed, 74 insertions(+)
>
> diff --git a/drivers/gpu/drm/selftests/drm_mm_selftests.h b/drivers/gpu/drm/selftests/drm_mm_selftests.h
> index 6b943ea1c57d..8c87c964176b 100644
> --- a/drivers/gpu/drm/selftests/drm_mm_selftests.h
> +++ b/drivers/gpu/drm/selftests/drm_mm_selftests.h
> @@ -14,6 +14,7 @@ selftest(insert, igt_insert)
>   selftest(replace, igt_replace)
>   selftest(insert_range, igt_insert_range)
>   selftest(align, igt_align)
> +selftest(frag, igt_frag)
>   selftest(align32, igt_align32)
>   selftest(align64, igt_align64)
>   selftest(evict, igt_evict)
> diff --git a/drivers/gpu/drm/selftests/test-drm_mm.c b/drivers/gpu/drm/selftests/test-drm_mm.c
> index 9aabe82dcd3a..05d8f3659b4d 100644
> --- a/drivers/gpu/drm/selftests/test-drm_mm.c
> +++ b/drivers/gpu/drm/selftests/test-drm_mm.c
> @@ -1033,6 +1033,79 @@ static int igt_insert_range(void *ignored)
>   	return 0;
>   }
>   
> +static int get_insert_time(unsigned int num_insert,
> +			   const struct insert_mode *mode)
> +{
> +	struct drm_mm mm;
> +	struct drm_mm_node *nodes, *node, *next;
> +	unsigned int size = 4096, align = 8192;
> +	unsigned long start;
> +	unsigned int i;
> +	int ret = -EINVAL;
> +
> +	drm_mm_init(&mm, 1, U64_MAX - 2);
> +	nodes = vzalloc(array_size(num_insert, sizeof(*nodes)));
> +	if (!nodes)
> +		goto err;
> +
> +	start = jiffies;
> +	for (i = 0; i < num_insert; i++) {
> +		if (!expect_insert(&mm, &nodes[i], size, align, i, mode)) {
> +			pr_err("%s insert failed\n", mode->name);
> +			goto out;
> +		}
> +	}
> +
> +	ret = jiffies_to_msecs(jiffies - start);
> +out:
> +	drm_mm_for_each_node_safe(node, next, &mm)
> +		drm_mm_remove_node(node);
> +	drm_mm_takedown(&mm);
> +	vfree(nodes);
> +err:
> +	return ret;
> +
> +}
> +
> +static int igt_frag(void *ignored)
> +{
> +	const struct insert_mode *mode;
> +	unsigned int insert_time1, insert_time2;
> +	unsigned int insert_size = 10000;
> +	unsigned int scale_factor = 4;
> +	/* tolerate 10% excess insertion duration */
> +	unsigned int error_factor = 110;
> +	int ret = -EINVAL;
> +
> +	for (mode = insert_modes; mode->name; mode++) {
> +		unsigned int expected_time;
> +
> +		insert_time1 = get_insert_time(insert_size, mode);
> +		if (insert_time1 < 0)
> +			goto err;
> +
> +		insert_time2 = get_insert_time((insert_size * 2), mode);
> +		if (insert_time2 < 0)
> +			goto err;
> +
> +		expected_time = (scale_factor * insert_time1 *
> +				 error_factor)/100;
> +		if (insert_time2 > expected_time) {
> +			pr_err("%s fragmented insert took more %u msecs\n",
> +			       mode->name, insert_time2 - expected_time);
> +			goto err;
> +		}
> +
> +		pr_info("%s fragmented insert of %u and %u insertions took %u and %u msecs\n",
> +			mode->name, insert_size, insert_size * 2, insert_time1,
> +			insert_time2);
> +	}
> +
> +	ret = 0;
> +err:
> +	return ret;
> +}
> +
>   static int igt_align(void *ignored)
>   {
>   	const struct insert_mode *mode;