Re: AMD graphics performance regression in 4.15 and later

From: Gabriel C <nix.or.die@gmail.com>
To: "Christian König" <christian.koenig@amd.com>
Cc: Jean-Marc Valin <jmvalin@mozilla.com>,
	Dave Airlie <airlied@linux.ie>,
	alexander.deucher@amd.com,
	Felix Kuehling <Felix.Kuehling@amd.com>,
	Laura Abbott <labbott@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	michel.daenzer@amd.com, dri-devel@lists.freedesktop.org,
	LKML <linux-kernel@vger.kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: AMD graphics performance regression in 4.15 and later
Date: Wed, 6 Jun 2018 14:08:28 +0200	[thread overview]
Message-ID: <CAEJqkgiBZ6G+tXWULYoGKqq3BsgvH7TrqkFbhtRL4JnGM+dLuA@mail.gmail.com> (raw)
In-Reply-To: <52eceaff-987d-4c1d-a2cb-73b28e48c01c@amd.com>

2018-06-06 13:33 GMT+02:00 Christian König <christian.koenig@amd.com>:
> Am 06.06.2018 um 13:28 schrieb Gabriel C:
>>
>> 2018-04-11 7:02 GMT+02:00 Gabriel C <nix.or.die@gmail.com>:
>>>>
>>>> 2018-04-11 6:00 GMT+02:00 Gabriel C <nix.or.die@gmail.com>:
>>>> 2018-04-09 11:42 GMT+02:00 Christian König
>>>> <ckoenig.leichtzumerken@gmail.com>:
>>>>>
>>>>> Am 07.04.2018 um 00:00 schrieb Jean-Marc Valin:
>>>
>>> ...
>>>>
>>>> I can help testing code for 4.17/++ if you wish but that is *different*
>>>> storry.
>>>>
>>> Quick tested an 4.16.0-11490-gb284d4d5a678 , amdgpu and radeon driver
>>> are broken now in this one.
>>>
>>> radeon tells:
>>>
>>> ...
>>>
>>> [    6.337838] [drm] PCIE GART of 2048M enabled (table at
>>> 0x00000000001D6000).
>>> [    6.338210] radeon 0000:21:00.0: (-12) create WB bo failed
>>> [    6.338214] radeon 0000:21:00.0: disabling GPU acceleration
>>>
>>> ...
>>>
>> I have the same Issue now on final 4.17.
>
>
> Actually Michel came up with a fix for the performance regression which is
> now backported to older kernels as well.
>
> So the original issue of this mail thread should be fixed by now.

Ok , will test as soon I get the GPU to work :))

>
>> Also I played with BIOS options also which does not fix anything but
>> changes the error message.
>>
>> IOMMU && SR-IOV disabled the error changes to this :
>>
>> [    7.092044] [drm:r600_ring_test [radeon]] *ERROR* radeon: ring 0
>> test failed (scratch(0x850C)=0xCAFEDEAD)
>> [    7.092059] radeon 0000:21:00.0: disabling GPU acceleration
>>
>>
>> While I could workaround SWIOTLB bugs in 4.15 and 4.16 , 4.17 seems to
>> kill the GPU with no way
>> for me to make it work ( at least I could not find any workaround by now )
>
>
> That actually sounds like something completely different. Can you provide a
> full dmesg of radeon and/or amdgpu?

Sure here from boot with IOMMU/SR-IOV ON/OFF in BIOS :

http://ftp.frugalware.org/pub/other/people/crazy/radeon/dmesg-iommu-sr-iov-off.txt
http://ftp.frugalware.org/pub/other/people/crazy/radeon/dmesg-iommu-sr-iov-on.txt

Also nothing else changed in that setup just testing kernel 4.17.

I can force the GPU to use amdgpu if you wish and post dmesg's too.
Just let me know