Am 13.11.2017 um 09:05 schrieb Chunming Zhou:
>
>
> On 2017å¹´11æ??13æ?¥ 15:51, Christian König wrote:
>> Am 13.11.2017 um 03:53 schrieb Chunming Zhou:
>>> Otherwise, they could be optimized by scheduled fence.
>>>
>>> Change-Id: I6857eee20aebeaad793d9fe4e1b5222f1be7470e
>>> Signed-off-by: Chunming Zhou <david1.zhou at amd.com>
>>
>> First of all patch is Reviewed-by: Christian König
>> <christian.koenig at amd.com>.
> Thanks.
>
>>
>> Second do you remember why we did this? I have some brief memory in
>> my head that a certain CTS test failed because we didn't completely
>> synchronized between dependencies explicit added by a semaphore.
> Yes, exactly, vulkan cts could fail for some semaphore case, which is
> to sync two job with different context but same process and same
> engine. Although two jobs are series in hw ring, their executions are
> in parallel, which could result in hang.
Ah, now I remember. Yeah the problem is that the two job executions
overlap and we need to insert an pipeline sync between them.
>
>>
>> Then can we narrow this down into a unit test for libdrm? Probably
>> not so easy to reproduce otherwise.
> Also yes, this is occasional issue, it's not very easy to reproduce.
Yeah, we would need to do something like job 1 writes a value A to
memory location X using shaders, then job 2 write to the same location
value B using the CP.
Then send both with a semaphore dependency between the two. If
everything works like expected we see value B, but if we don't wait for
the shaders to finish before running job 2 we see value A.
Do you have time to put all this into a unit tests? I think that would
be important to make sure we don't break it again in the future.
Otherwise Andrey can probably take a look.
Regards,
Christian.
>
> Regards,
> David Zhou
>>
>> Thanks,
>> Christian.
>>
>>> ---
>>> Â drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 4 ++--
>>> Â 1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>>> index 673fb9f4301e..4a2af571d35f 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>>> @@ -1078,7 +1078,7 @@ static int amdgpu_cs_process_fence_dep(struct
>>> amdgpu_cs_parser *p,
>>> Â Â Â Â Â Â Â Â Â Â Â Â Â amdgpu_ctx_put(ctx);
>>> Â Â Â Â Â Â Â Â Â Â Â Â Â return r;
>>> Â Â Â Â Â Â Â Â Â } else if (fence) {
>>> -Â Â Â Â Â Â Â Â Â Â Â r = amdgpu_sync_fence(p->adev, &p->job->sync,
>>> +Â Â Â Â Â Â Â Â Â Â Â r = amdgpu_sync_fence(p->adev, &p->job->dep_sync,
>>> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â fence);
>>> Â Â Â Â Â Â Â Â Â Â Â Â Â dma_fence_put(fence);
>>> Â Â Â Â Â Â Â Â Â Â Â Â Â amdgpu_ctx_put(ctx);
>>> @@ -1103,7 +1103,7 @@ static int
>>> amdgpu_syncobj_lookup_and_add_to_sync(struct amdgpu_cs_parser *p,
>>> Â Â Â Â Â if (r)
>>> Â Â Â Â Â Â Â Â Â return r;
>>> Â -Â Â Â r = amdgpu_sync_fence(p->adev, &p->job->sync, fence);
>>> +Â Â Â r = amdgpu_sync_fence(p->adev, &p->job->dep_sync, fence);
>>> Â Â Â Â Â dma_fence_put(fence);
>>> Â Â Â Â Â Â return r;
>>
>>
>
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