[RFC PATCH 1/1] drm/mm: add ig_frag selftest
Christian König
christian.koenig at amd.com
Tue Jun 2 12:47:43 UTC 2020
Nirmoy please keep in mind that your current implementation doesn't
fully solve the issue the test case is exercising.
In other words what you have implement is fast skipping of fragmented
address space for bottom-up and top-down.
But what this test here exercises is the fast skipping of aligned
allocations. You should probably adjust the test case a bit.
Regards,
Christian.
Am 29.05.20 um 23:01 schrieb Nirmoy:
>
> 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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