[PATCH 2/2] drm/amdgpu: bind GTT on demand

Christian König deathsimple at vodafone.de
Wed Sep 7 16:26:14 UTC 2016


> The patch looks good to me. Thanks for tackling this. I didn't review it
> too thoroughly, and if you forgot to map to GART somewhere important, I
> would probably have missed it.

Yeah that's also my biggest concern, but that should at least raise a 
WARN_ON().

> Acked-by: Felix Kuehling <Felix.Kuehling at amd.com>
Thanks.

> Once we pull this change into the KFD branch, we can probably revert our
> ridiculous GART size without losing the ability to map lots of system
> memory to GPUVM. :)
Wait a second with that. You also need my second part of that work where 
I also stop assigning address space to all those buffers which aren't 
mapped.

But I'm still working on that.

Regards,
Christian.

Am 07.09.2016 um 18:07 schrieb Felix Kuehling:
> Yeah, you save yourself the GTT update, which always uses the CPU.
> Instead you write the page table entries to IBs using the CPU. Will be
> interesting to see if that's a net speed-up or slow-down, if the
> difference is significant at all.
>
> The patch looks good to me. Thanks for tackling this. I didn't review it
> too thoroughly, and if you forgot to map to GART somewhere important, I
> would probably have missed it.
>
> Acked-by: Felix Kuehling <Felix.Kuehling at amd.com>
>
> Once we pull this change into the KFD branch, we can probably revert our
> ridiculous GART size without losing the ability to map lots of system
> memory to GPUVM. :)
>
> Regards,
>    Felix
>
> On 16-09-07 04:18 AM, Christian König wrote:
>> Am 07.09.2016 um 09:18 schrieb zhoucm1:
>>>
>>> On 2016年09月06日 18:48, Christian König wrote:
>>>> Am 06.09.2016 um 11:53 schrieb zhoucm1:
>>>>>
>>>>> On 2016年09月06日 17:41, Christian König wrote:
>>>>>> From: Christian König <christian.koenig at amd.com>
>>>>>>
>>>>>> We don't really need the GTT table any more most of the time.
>>>>> Why? I thought GTT bo is always needed to be bound when GPU is
>>>>> trying to access it, doesn't it?
>>>> We only need it to be bound when we try to access it from the system
>>>> VM (UVD/VCE, ring buffers, fences etc...).
>>>>
>>>> The VMs for each process can work without it and it is just overhead
>>>> to bind it all the time.
>>> Yes, I got your mean, copying pte from GART to VM confused me, I
>>> thought binding GTT table is a must, that's wrong.
>>> Go though vm code again, pte can be created by amdgpu_vm_map_gart if
>>> no GTT pte source when we don't bind it at all under VM process, am I
>>> right now?
>> Yes exactly. I still need to measure the performance impact of that,
>> adding the copy from the GTT made quite a difference when I introduced
>> that.
>>
>> I hope that doing the write when the update the VM is still faster
>> than doing the GTT write.
>>
>> Regards,
>> Christian.
>>
>>> Regards,
>>> David Zhou
>>>
>>>> Regards,
>>>> Christian.
>>>>
>>>>
>>>>> Regards,
>>>>> David Zhou
>>>>>>    So bind it
>>>>>> only on demand.
>>>>>>
>>>>>> Signed-off-by: Christian König <christian.koenig at amd.com>
>>>>>> ---
>>>>>>    drivers/gpu/drm/amd/amdgpu/amdgpu.h        |  1 +
>>>>>>    drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c     | 34
>>>>>> ++++++++++++++++++++++++++++--
>>>>>>    drivers/gpu/drm/amd/amdgpu/amdgpu_object.c |  7 ++++++
>>>>>>    drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c    | 33
>>>>>> ++++++++++++++++++++++++++---
>>>>>>    drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h    |  3 +++
>>>>>>    drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c    |  4 ++++
>>>>>>    drivers/gpu/drm/amd/amdgpu/amdgpu_vce.c    |  6 +++++-
>>>>>>    drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c     |  3 ++-
>>>>>>    8 files changed, 84 insertions(+), 7 deletions(-)
>>>>>>
>>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>>>>>> index 9d39fa8..28d4a67 100644
>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>>>>>> @@ -2521,6 +2521,7 @@ static inline void amdgpu_acpi_fini(struct
>>>>>> amdgpu_device *adev) { }
>>>>>>    struct amdgpu_bo_va_mapping *
>>>>>>    amdgpu_cs_find_mapping(struct amdgpu_cs_parser *parser,
>>>>>>                   uint64_t addr, struct amdgpu_bo **bo);
>>>>>> +int amdgpu_cs_sysvm_access_required(struct amdgpu_cs_parser
>>>>>> *parser);
>>>>>>      #if defined(CONFIG_DRM_AMD_DAL)
>>>>>>    int amdgpu_dm_display_resume(struct amdgpu_device *adev );
>>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>>>>>> index 20a1962..e069978 100644
>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>>>>>> @@ -640,8 +640,12 @@ static int amdgpu_cs_parser_bos(struct
>>>>>> amdgpu_cs_parser *p,
>>>>>>            }
>>>>>>        }
>>>>>>    -    if (p->uf_entry.robj)
>>>>>> -        p->job->uf_addr += amdgpu_bo_gpu_offset(p->uf_entry.robj);
>>>>>> +    if (!r && p->uf_entry.robj) {
>>>>>> +        struct amdgpu_bo *uf = p->uf_entry.robj;
>>>>>> +
>>>>>> +        r = amdgpu_ttm_bind(uf->tbo.ttm, &uf->tbo.mem);
>>>>>> +        p->job->uf_addr += amdgpu_bo_gpu_offset(uf);
>>>>>> +    }
>>>>>>      error_validate:
>>>>>>        if (r) {
>>>>>> @@ -1156,3 +1160,29 @@ amdgpu_cs_find_mapping(struct
>>>>>> amdgpu_cs_parser *parser,
>>>>>>          return NULL;
>>>>>>    }
>>>>>> +
>>>>>> +/**
>>>>>> + * amdgpu_cs_sysvm_access_required - make BOs accessible by the
>>>>>> system VM
>>>>>> + *
>>>>>> + * @parser: command submission parser context
>>>>>> + *
>>>>>> + * Helper for UVD/VCE VM emulation, make sure BOs are accessible
>>>>>> by the system VM.
>>>>>> + */
>>>>>> +int amdgpu_cs_sysvm_access_required(struct amdgpu_cs_parser *parser)
>>>>>> +{
>>>>>> +    unsigned i;
>>>>>> +    int r;
>>>>>> +
>>>>>> +    if (!parser->bo_list)
>>>>>> +        return 0;
>>>>>> +
>>>>>> +    for (i = 0; i < parser->bo_list->num_entries; i++) {
>>>>>> +        struct amdgpu_bo *bo = parser->bo_list->array[i].robj;
>>>>>> +
>>>>>> +        r = amdgpu_ttm_bind(bo->tbo.ttm, &bo->tbo.mem);
>>>>>> +        if (unlikely(r))
>>>>>> +            return r;
>>>>>> +    }
>>>>>> +
>>>>>> +    return 0;
>>>>>> +}
>>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>>>>> index b17734e..dc73f11 100644
>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>>>>> @@ -646,6 +646,11 @@ int amdgpu_bo_pin_restricted(struct amdgpu_bo
>>>>>> *bo, u32 domain,
>>>>>>            dev_err(bo->adev->dev, "%p pin failed\n", bo);
>>>>>>            goto error;
>>>>>>        }
>>>>>> +    r = amdgpu_ttm_bind(bo->tbo.ttm, &bo->tbo.mem);
>>>>>> +    if (unlikely(r)) {
>>>>>> +        dev_err(bo->adev->dev, "%p bind failed\n", bo);
>>>>>> +        goto error;
>>>>>> +    }
>>>>>>          bo->pin_count = 1;
>>>>>>        if (gpu_addr != NULL)
>>>>>> @@ -918,6 +923,8 @@ void amdgpu_bo_fence(struct amdgpu_bo *bo,
>>>>>> struct fence *fence,
>>>>>>    u64 amdgpu_bo_gpu_offset(struct amdgpu_bo *bo)
>>>>>>    {
>>>>>>        WARN_ON_ONCE(bo->tbo.mem.mem_type == TTM_PL_SYSTEM);
>>>>>> +    WARN_ON_ONCE(bo->tbo.mem.mem_type == TTM_PL_TT &&
>>>>>> +             !amdgpu_ttm_is_bound(bo->tbo.ttm));
>>>>>> WARN_ON_ONCE(!ww_mutex_is_locked(&bo->tbo.resv->lock) &&
>>>>>>                 !bo->pin_count);
>>>>>>    diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>>>>>> index 4337b3a..c294aa9 100644
>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>>>>>> @@ -256,8 +256,12 @@ static int amdgpu_move_blit(struct
>>>>>> ttm_buffer_object *bo,
>>>>>>        new_start = (u64)new_mem->start << PAGE_SHIFT;
>>>>>>          switch (old_mem->mem_type) {
>>>>>> -    case TTM_PL_VRAM:
>>>>>>        case TTM_PL_TT:
>>>>>> +        r = amdgpu_ttm_bind(bo->ttm, old_mem);
>>>>>> +        if (r)
>>>>>> +            return r;
>>>>>> +
>>>>>> +    case TTM_PL_VRAM:
>>>>>>            old_start += bo->bdev->man[old_mem->mem_type].gpu_offset;
>>>>>>            break;
>>>>>>        default:
>>>>>> @@ -265,8 +269,12 @@ static int amdgpu_move_blit(struct
>>>>>> ttm_buffer_object *bo,
>>>>>>            return -EINVAL;
>>>>>>        }
>>>>>>        switch (new_mem->mem_type) {
>>>>>> -    case TTM_PL_VRAM:
>>>>>>        case TTM_PL_TT:
>>>>>> +        r = amdgpu_ttm_bind(bo->ttm, new_mem);
>>>>>> +        if (r)
>>>>>> +            return r;
>>>>>> +
>>>>>> +    case TTM_PL_VRAM:
>>>>>>            new_start += bo->bdev->man[new_mem->mem_type].gpu_offset;
>>>>>>            break;
>>>>>>        default:
>>>>>> @@ -639,7 +647,6 @@ static int amdgpu_ttm_backend_bind(struct
>>>>>> ttm_tt *ttm,
>>>>>>                       struct ttm_mem_reg *bo_mem)
>>>>>>    {
>>>>>>        struct amdgpu_ttm_tt *gtt = (void*)ttm;
>>>>>> -    uint32_t flags = amdgpu_ttm_tt_pte_flags(gtt->adev, ttm,
>>>>>> bo_mem);
>>>>>>        int r;
>>>>>>          if (gtt->userptr) {
>>>>>> @@ -660,6 +667,26 @@ static int amdgpu_ttm_backend_bind(struct
>>>>>> ttm_tt *ttm,
>>>>>>            bo_mem->mem_type == AMDGPU_PL_OA)
>>>>>>            return -EINVAL;
>>>>>>    +    return 0;
>>>>>> +}
>>>>>> +
>>>>>> +bool amdgpu_ttm_is_bound(struct ttm_tt *ttm)
>>>>>> +{
>>>>>> +    struct amdgpu_ttm_tt *gtt = (void *)ttm;
>>>>>> +
>>>>>> +    return gtt && !list_empty(&gtt->list);
>>>>>> +}
>>>>>> +
>>>>>> +int amdgpu_ttm_bind(struct ttm_tt *ttm, struct ttm_mem_reg *bo_mem)
>>>>>> +{
>>>>>> +    struct amdgpu_ttm_tt *gtt = (void *)ttm;
>>>>>> +    uint32_t flags;
>>>>>> +    int r;
>>>>>> +
>>>>>> +    if (!ttm || amdgpu_ttm_is_bound(ttm))
>>>>>> +        return 0;
>>>>>> +
>>>>>> +    flags = amdgpu_ttm_tt_pte_flags(gtt->adev, ttm, bo_mem);
>>>>>>        r = amdgpu_gart_bind(gtt->adev, gtt->offset, ttm->num_pages,
>>>>>>            ttm->pages, gtt->ttm.dma_address, flags);
>>>>>>    diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
>>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
>>>>>> index 72f6bfc..214bae9 100644
>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
>>>>>> @@ -77,4 +77,7 @@ int amdgpu_fill_buffer(struct amdgpu_bo *bo,
>>>>>>                struct fence **fence);
>>>>>>      int amdgpu_mmap(struct file *filp, struct vm_area_struct *vma);
>>>>>> +bool amdgpu_ttm_is_bound(struct ttm_tt *ttm);
>>>>>> +int amdgpu_ttm_bind(struct ttm_tt *ttm, struct ttm_mem_reg *bo_mem);
>>>>>> +
>>>>>>    #endif
>>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c
>>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c
>>>>>> index 5888e8a..fab7bb1 100644
>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c
>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c
>>>>>> @@ -891,6 +891,10 @@ int amdgpu_uvd_ring_parse_cs(struct
>>>>>> amdgpu_cs_parser *parser, uint32_t ib_idx)
>>>>>>            return -EINVAL;
>>>>>>        }
>>>>>>    +    r = amdgpu_cs_sysvm_access_required(parser);
>>>>>> +    if (r)
>>>>>> +        return r;
>>>>>> +
>>>>>>        ctx.parser = parser;
>>>>>>        ctx.buf_sizes = buf_sizes;
>>>>>>        ctx.ib_idx = ib_idx;
>>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vce.c
>>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vce.c
>>>>>> index 9b71d6c..b0c6702 100644
>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vce.c
>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vce.c
>>>>>> @@ -634,7 +634,11 @@ int amdgpu_vce_ring_parse_cs(struct
>>>>>> amdgpu_cs_parser *p, uint32_t ib_idx)
>>>>>>        uint32_t allocated = 0;
>>>>>>        uint32_t tmp, handle = 0;
>>>>>>        uint32_t *size = &tmp;
>>>>>> -    int i, r = 0, idx = 0;
>>>>>> +    int i, r, idx = 0;
>>>>>> +
>>>>>> +    r = amdgpu_cs_sysvm_access_required(p);
>>>>>> +    if (r)
>>>>>> +        return r;
>>>>>>          while (idx < ib->length_dw) {
>>>>>>            uint32_t len = amdgpu_get_ib_value(p, ib_idx, idx);
>>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>>>>> index 7660f82..a549abd 100644
>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>>>>> @@ -1162,7 +1162,8 @@ int amdgpu_vm_bo_update(struct amdgpu_device
>>>>>> *adev,
>>>>>>        }
>>>>>>          flags = amdgpu_ttm_tt_pte_flags(adev, bo_va->bo->tbo.ttm,
>>>>>> mem);
>>>>>> -    gtt_flags = (adev == bo_va->bo->adev) ? flags : 0;
>>>>>> +    gtt_flags = (amdgpu_ttm_is_bound(bo_va->bo->tbo.ttm) &&
>>>>>> +        adev == bo_va->bo->adev) ? flags : 0;
>>>>>>          spin_lock(&vm->status_lock);
>>>>>>        if (!list_empty(&bo_va->vm_status))
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