[Intel-gfx] Performance drop using deinterlace_vaapi on 5.19-rcX

[Christian König]

Hi Thomas,

Am 20.06.22 um 16:31 schrieb Thomas Voegtle:
> On Mon, 20 Jun 2022, Christian König wrote:
>
>> Am 20.06.22 um 13:40 schrieb Thomas Voegtle:
>>>  On Mon, 20 Jun 2022, Christian König wrote:
>>>
>>>>  Hi Thomas,
>>>>
>>>>  [moving vger to bcc]
>>>>
>>>>  mhm, sounds like something isn't running in parallel any more.
>>>>
>>>>  We usually don't test the multimedia engines for this but we do test
>>>>  gfx+compute, so I'm really wondering what goes wrong here.
>>>>
>>>>  Could you run some tests for me? Additional to that I'm going to 
>>>> raise
>>>>  that issue with our multimedia guys later today.
>>>
>>>  Yes, I can run some tests for you. Which tests?
>>
>> Try this as root:
>>
>> echo 1 > 
>> /sys/kernel/debug/tracing/events/dma_fence/dma_fence_init/enable
>> echo 1 > 
>> /sys/kernel/debug/tracing/events/dma_fence/dma_fence_signaled/enable
>> cat /sys/kernel/debug/tracing/trace_pipe > trace.log
>>
>> Then start the encoding in another shell, after it completed cancel 
>> the cat with cntr+c and save the log file.
>>
>> Do this one with the old kernel and once with the new one.
>
>
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2F32h.de%2Ftv%2F5.18.0-i5-trace.log.bz2&data=05%7C01%7Cchristian.koenig%40amd.com%7C41a052960a4d4f7dd38e08da52c99097%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637913323382588469%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=xv8vLUuBq37sBFcGxdua%2FnNQ51BiN1USn30ehP8bys0%3D&reserved=0
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2F32h.de%2Ftv%2F5.19.0-rc3-i5-trace.log.bz2&data=05%7C01%7Cchristian.koenig%40amd.com%7C41a052960a4d4f7dd38e08da52c99097%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637913323382588469%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=xuBVrQMQ%2FDK3Gv1qN%2FntJ9NjXOZxD6XVkmDCWfG4K44%3D&reserved=0
>
>
> I hope I have done this correctly.
> All necessary tracing things switched on?

Yeah, that looks like what I wanted to see.

>
> I want to add that this is a headless machine. No monitor connected.
>

I've just realized that you aren't even using any AMD GPU for 
transcoding, so I have no idea why removing the AMD specific workaround 
can cause a performance problem for i915.

It must be somehow related to i915 now adding some additional 
synchronization in between submissions.

Adding the Intel mailing list, maybe somebody has a better idea.

Regards,
Christian.