[PATCH] drm/amdgpu: remove distinction between explicit and implicit sync (v2)

Chunming Zhou zhoucm1 at amd.com
Wed Jun 10 07:55:54 UTC 2020

在 2020/6/10 15:41, Christian König 写道:
> That's true, but for now we are stuck with the implicit sync for quite 
> a number of use cases.
> My problem is rather that we already tried this and it backfired 
> immediately.
> I do remember that it was your patch who introduced the pipeline sync 
> flag handling and I warned that this could be problematic. You then 
> came back with a QA result saying that this is indeed causing a huge 
> performance drop in one test case and we need to do something else. 
> Together we then came up with the different handling between implicit 
> and explicit sync.

Isn't pipeline sync flag to fix some issue because of parralel execution 
between jobs in one pipeline?  I really don't have this memory in mind 
why that's realted to this, Or do you mean extra sync hides many other 
potential issues?

Anyway, when I go through Vulkan WSI code, the synchronization isn't so 
smooth between OS window system. And when I saw Jason drives explicit 
sync through the whole Linux ecosystem like Android window system does, 
I feel that's really a good direction.


> But I can't find that stupid mail thread any more. I knew that it was 
> a couple of years ago when we started with the explicit sync for Vulkan.
> Christian.
> Am 10.06.20 um 08:29 schrieb Zhou, David(ChunMing):
>> [AMD Official Use Only - Internal Distribution Only]
>> Not sue if this is right direction, I think usermode wants all 
>> synchronizations to be explicit. Implicit sync often confuses people 
>> who don’t know its history. I remember Jason from Intel  is driving 
>> explicit synchronization through the Linux ecosystem, which even 
>> removes implicit sync of shared buffer.
>> -David
>> *From:* amd-gfx <amd-gfx-bounces at lists.freedesktop.org> *On Behalf Of 
>> *Marek Olšák
>> *Sent:* Tuesday, June 9, 2020 6:58 PM
>> *To:* amd-gfx mailing list <amd-gfx at lists.freedesktop.org>
>> *Subject:* [PATCH] drm/amdgpu: remove distinction between explicit 
>> and implicit sync (v2)
>> Hi,
>> This enables a full pipeline sync for implicit sync. It's Christian's 
>> patch with the driver version bumped. With this, user mode drivers 
>> don't have to wait for idle at the end of gfx IBs.
>> Any concerns?
>> Thanks,
>> Marek
>> _______________________________________________
>> amd-gfx mailing list
>> amd-gfx at lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
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