[RFC PATCH 1/1] drm/mm: add ig_frag selftest
Nirmoy
nirmodas at amd.com
Fri May 29 21:01:04 UTC 2020
On 5/29/20 5:52 PM, Chris Wilson wrote:
> Quoting Nirmoy (2020-05-29 16:40:53)
>> This works correctly most of the times but sometimes
I have to take my word back. In another machine, 20k insertions in
best mode takes 6-9 times more than 10k insertions, all most all the time.
evict, bottom-up and top-down modes remains in 2-5 times range.
If I reduce the insertions to 1k and 2k then scaling factor for best
mode stays below 4 most of the time.
evict, bottom-up and top-down modes remains in 2-3 times range.
I wonder if it makes sense to test with only 1k and 2k insertions and
tolerate more than error if the mode == best.
Regards,
Nirmoy
>>
>> 20k insertions can take more than 8 times of 10k insertion time.
> The pressure is on to improve then :)
>
>> 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;
> Use ktime_t start = ktime_now();
>
>>> + 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);
> ret = ktime_sub(ktime_now(), start);
>
> The downside to using ktime is remembering it is s64 and so requires care
> and attention in doing math.
>
>>> +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;
> Ah, can you propagate the actual error. I see you are returning EINVAL
> for ENOMEM errors. Just wait until it hits and you have to debug why :)
>
>>> + 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);
> Put the info first before the error. We always want the full details,
> with the error message explaining why it's unhappy.
> -Chris
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