On 2019-10-25 12:19 p.m., Koenig, Christian wrote:
> Am 25.10.19 um 18:05 schrieb Alex Deucher:
>> On Fri, Oct 25, 2019 at 2:49 AM Koenig, Christian
>> <Christian.Koenig@xxxxxxx> wrote:
>>> Am 24.10.19 um 23:16 schrieb Tuikov, Luben:
>>>> The GRBM interface is now capable of bursting
>>>> 1-cycle op per register, a WRITE followed by
>>>> another WRITE, or a WRITE followed by a READ--much
>>>> faster than previous muti-cycle per
>>>> completed-transaction interface. This causes a
>>>> problem, whereby status registers requiring a
>>>> read/write by hardware, have a 1-cycle delay, due
>>>> to the register update having to go through GRBM
>>>> interface.
>>>>
>>>> This patch adds this delay.
>>>>
>>>> A one cycle read op is added after updating the
>>>> invalidate request and before reading the
>>>> invalidate-ACK status.
>>> Please completely drop all changes for GFX9 since this patch will most
>>> likely break SRIOV.
>>>
>>> Additional to that please apply the workaround only to SDMA since the CP
>>> driven engines should handle that in firmware.
Thank you Christian for reviewing this patch.
This patch stirred quite a bit of noise. So, then, I'll go by
your last comment above--I suppose this is the desired way to go forward then?
Regards,
Luben
>> I think the CP only handles this in firmware if we use the new TLB
>> invalidation packet. I don't think it applies it to general register
>> writes like we do.
>
> No, on the CP we should use the combined write/wait command even if we
> don't use the new specialized VM invalidate command. Everything else
> won't work with SRIOV.
>
> Even if we want to we can't insert an extra read in this combined
> write/wait command. And if we split up the commands we would break SRIOV
> once more.
>
> So applying this workaround to the CP code doesn't make any sense at all.
>
> The only TODO which I can see is that we maybe don't use the combined
> write/wait command on Navi yet.
>
> Christian.
>
>>
>> Alex
>>
>>> Regards,
>>> Christian.
>>>
>>>> See also commit
>>>> 534991731cb5fa94b5519957646cf849ca10d17d.
>>>>
>>>> Signed-off-by: Luben Tuikov <luben.tuikov@xxxxxxx>
>>>> ---
>>>> drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c | 4 ++--
>>>> drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c | 4 ++--
>>>> drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c | 9 +++++++++
>>>> drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c | 8 ++++++++
>>>> drivers/gpu/drm/amd/amdgpu/sdma_v5_0.c | 2 +-
>>>> 5 files changed, 22 insertions(+), 5 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c b/drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c
>>>> index ac43b1af69e3..0042868dbd53 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c
>>>> @@ -5129,7 +5129,7 @@ static const struct amdgpu_ring_funcs gfx_v10_0_ring_funcs_gfx = {
>>>> 5 + /* COND_EXEC */
>>>> 7 + /* PIPELINE_SYNC */
>>>> SOC15_FLUSH_GPU_TLB_NUM_WREG * 5 +
>>>> - SOC15_FLUSH_GPU_TLB_NUM_REG_WAIT * 7 +
>>>> + SOC15_FLUSH_GPU_TLB_NUM_REG_WAIT * 7 * 2 +
>>>> 2 + /* VM_FLUSH */
>>>> 8 + /* FENCE for VM_FLUSH */
>>>> 20 + /* GDS switch */
>>>> @@ -5182,7 +5182,7 @@ static const struct amdgpu_ring_funcs gfx_v10_0_ring_funcs_compute = {
>>>> 5 + /* hdp invalidate */
>>>> 7 + /* gfx_v10_0_ring_emit_pipeline_sync */
>>>> SOC15_FLUSH_GPU_TLB_NUM_WREG * 5 +
>>>> - SOC15_FLUSH_GPU_TLB_NUM_REG_WAIT * 7 +
>>>> + SOC15_FLUSH_GPU_TLB_NUM_REG_WAIT * 7 * 2 +
>>>> 2 + /* gfx_v10_0_ring_emit_vm_flush */
>>>> 8 + 8 + 8, /* gfx_v10_0_ring_emit_fence x3 for user fence, vm fence */
>>>> .emit_ib_size = 7, /* gfx_v10_0_ring_emit_ib_compute */
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c b/drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c
>>>> index 9fe95e7693d5..9a7a717208de 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c
>>>> @@ -6218,7 +6218,7 @@ static const struct amdgpu_ring_funcs gfx_v9_0_ring_funcs_gfx = {
>>>> 5 + /* COND_EXEC */
>>>> 7 + /* PIPELINE_SYNC */
>>>> SOC15_FLUSH_GPU_TLB_NUM_WREG * 5 +
>>>> - SOC15_FLUSH_GPU_TLB_NUM_REG_WAIT * 7 +
>>>> + SOC15_FLUSH_GPU_TLB_NUM_REG_WAIT * 7 * 2 +
>>>> 2 + /* VM_FLUSH */
>>>> 8 + /* FENCE for VM_FLUSH */
>>>> 20 + /* GDS switch */
>>>> @@ -6271,7 +6271,7 @@ static const struct amdgpu_ring_funcs gfx_v9_0_ring_funcs_compute = {
>>>> 5 + /* hdp invalidate */
>>>> 7 + /* gfx_v9_0_ring_emit_pipeline_sync */
>>>> SOC15_FLUSH_GPU_TLB_NUM_WREG * 5 +
>>>> - SOC15_FLUSH_GPU_TLB_NUM_REG_WAIT * 7 +
>>>> + SOC15_FLUSH_GPU_TLB_NUM_REG_WAIT * 7 * 2 +
>>>> 2 + /* gfx_v9_0_ring_emit_vm_flush */
>>>> 8 + 8 + 8, /* gfx_v9_0_ring_emit_fence x3 for user fence, vm fence */
>>>> .emit_ib_size = 7, /* gfx_v9_0_ring_emit_ib_compute */
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c
>>>> index 6e1b25bd1fe7..100d526e9a42 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c
>>>> @@ -346,6 +346,15 @@ static uint64_t gmc_v10_0_emit_flush_gpu_tlb(struct amdgpu_ring *ring,
>>>>
>>>> amdgpu_ring_emit_wreg(ring, hub->vm_inv_eng0_req + eng, req);
>>>>
>>>> + /* Insert a dummy read to delay one cycle before the ACK
>>>> + * inquiry.
>>>> + */
>>>> + if (ring->funcs->type == AMDGPU_RING_TYPE_SDMA ||
>>>> + ring->funcs->type == AMDGPU_RING_TYPE_GFX ||
>>>> + ring->funcs->type == AMDGPU_RING_TYPE_COMPUTE)
>>>> + amdgpu_ring_emit_reg_wait(ring,
>>>> + hub->vm_inv_eng0_req + eng, 0, 0);
>>>> +
>>>> /* wait for the invalidate to complete */
>>>> amdgpu_ring_emit_reg_wait(ring, hub->vm_inv_eng0_ack + eng,
>>>> 1 << vmid, 1 << vmid);
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
>>>> index 9f2a893871ec..8f3097e45299 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
>>>> @@ -495,6 +495,14 @@ static uint64_t gmc_v9_0_emit_flush_gpu_tlb(struct amdgpu_ring *ring,
>>>> amdgpu_ring_emit_wreg(ring, hub->ctx0_ptb_addr_hi32 + (2 * vmid),
>>>> upper_32_bits(pd_addr));
>>>>
>>>> + /* Insert a dummy read to delay one cycle before the ACK
>>>> + * inquiry.
>>>> + */
>>>> + if (ring->funcs->type == AMDGPU_RING_TYPE_GFX ||
>>>> + ring->funcs->type == AMDGPU_RING_TYPE_COMPUTE)
>>>> + amdgpu_ring_emit_reg_wait(ring,
>>>> + hub->vm_inv_eng0_req + eng, 0, 0);
>>>> +
>>>> amdgpu_ring_emit_reg_write_reg_wait(ring, hub->vm_inv_eng0_req + eng,
>>>> hub->vm_inv_eng0_ack + eng,
>>>> req, 1 << vmid);
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/sdma_v5_0.c b/drivers/gpu/drm/amd/amdgpu/sdma_v5_0.c
>>>> index b8fdb192f6d6..0c41b4fdc58b 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/sdma_v5_0.c
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/sdma_v5_0.c
>>>> @@ -1588,7 +1588,7 @@ static const struct amdgpu_ring_funcs sdma_v5_0_ring_funcs = {
>>>> 6 + /* sdma_v5_0_ring_emit_pipeline_sync */
>>>> /* sdma_v5_0_ring_emit_vm_flush */
>>>> SOC15_FLUSH_GPU_TLB_NUM_WREG * 3 +
>>>> - SOC15_FLUSH_GPU_TLB_NUM_REG_WAIT * 6 +
>>>> + SOC15_FLUSH_GPU_TLB_NUM_REG_WAIT * 6 * 2 +
>>>> 10 + 10 + 10, /* sdma_v5_0_ring_emit_fence x3 for user fence, vm fence */
>>>> .emit_ib_size = 7 + 6, /* sdma_v5_0_ring_emit_ib */
>>>> .emit_ib = sdma_v5_0_ring_emit_ib,
>>> _______________________________________________
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>
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