[PATCH] drm/amdgpu: fix ocl test performance drop

[Christian König]

I'm pretty sure that bug is fixed in GFX9. So we don't need the check 
there any more.

Regards,
Christian.

Am 19.05.2017 um 07:16 schrieb zhoucm1:
> I also realized this problem when I did fix for sched fence, I thought 
> if no issue, just left it as current code, it's more safe.
> As Flora point it out, it results in performance drop, then we need to 
> correct it back.
> pipeline_sync in vm flush should be inserted only when 
> amdgpu_vm_ring_has_compute_vm_bug() is true, not all time for every vm 
> flush for all engines. The bug has been fixed in mec firmware from 
> version 673 in gfx8.
> About gfx9 for amdgpu_vm_ring_has_compute_vm_bug(), current 
> implementation is thinking gfx9 doesn't have compute vm bug by 
> default. Not sure it's in there. If no vm fault related to this bug, 
> then we can think gfx9 has no compute vm bug, I believe firmware team 
> does that based on previous generation, otherwise we need identify 
> every generation, that's crazy.
>
> Regards,
> David Zhou
> On 2017年05月19日 11:36, Flora Cui wrote:
>> btw, what's about gfx9 for amdgpu_vm_ring_has_compute_vm_bug()? Is the
>> workaround still needed?
>>
>> On Fri, May 19, 2017 at 10:25:19AM +0800, Flora Cui wrote:
>>> On Thu, May 18, 2017 at 01:38:15PM +0200, Christian König wrote:
>>>> Am 18.05.2017 um 09:45 schrieb Flora Cui:
>>>>> partial revert commit <6971d3d> - drm/amdgpu: cleanup logic in
>>>>> amdgpu_vm_flush
>>>>>
>>>>> Change-Id: Iadce9d613dfe9a739643a74050cea55854832adb
>>>>> Signed-off-by: Flora Cui <Flora.Cui at amd.com>
>>>> I don't see how the revert should be faster than the original.
>>>>
>>>> Especially that amdgpu_vm_had_gpu_reset() is now called twice 
>>>> sounds like
>>>> more overhead than necessary.
>>>>
>>>> Please explain further.
>>>>
>>>> Christian.
>>>>
>>>>> ---
>>>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 14 +++++---------
>>>>>   1 file changed, 5 insertions(+), 9 deletions(-)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c 
>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>>>> index 88420dc..a96bad6 100644
>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>>>> @@ -743,23 +743,19 @@ int amdgpu_vm_flush(struct amdgpu_ring 
>>>>> *ring, struct amdgpu_job *job)
>>>>>           id->gws_size != job->gws_size ||
>>>>>           id->oa_base != job->oa_base ||
>>>>>           id->oa_size != job->oa_size);
>>>>> -    bool vm_flush_needed = job->vm_needs_flush ||
>>>>> -        amdgpu_vm_ring_has_compute_vm_bug(ring);
>>>>>       unsigned patch_offset = 0;
>>>>>       int r;
>>>>> -    if (amdgpu_vm_had_gpu_reset(adev, id)) {
>>>>> -        gds_switch_needed = true;
>>>>> -        vm_flush_needed = true;
>>>>> -    }
>>>>> -
>>>>> -    if (!vm_flush_needed && !gds_switch_needed)
>>>>> +    if (!job->vm_needs_flush && !gds_switch_needed &&
>>>>> +        !amdgpu_vm_had_gpu_reset(adev, id) &&
>>>>> +        !amdgpu_vm_ring_has_compute_vm_bug(ring))
>>>>>           return 0;
>>>>>       if (ring->funcs->init_cond_exec)
>>>>>           patch_offset = amdgpu_ring_init_cond_exec(ring);
>>>>> -    if (ring->funcs->emit_vm_flush && vm_flush_needed) {
>>> [flora]: for compute ring & amdgpu_vm_ring_has_compute_vm_bug(), a 
>>> vm_flush is
>>> inserted. This might cause performance drop.
>>>>> +    if (ring->funcs->emit_vm_flush &&
>>>>> +        (job->vm_needs_flush || amdgpu_vm_had_gpu_reset(adev, 
>>>>> id))) {
>>>>>           struct fence *fence;
>>>>>           trace_amdgpu_vm_flush(ring, job->vm_id, job->vm_pd_addr);
>>>>
>>> _______________________________________________
>>> amd-gfx mailing list
>>> amd-gfx at lists.freedesktop.org
>>> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
>> _______________________________________________
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>> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
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