Christian

What we want to do is like:
Read reg value from RLC_SPM_MC_CNTL to tmp
Set bits:3:0 to VMID  to tmp
Write tmp to RLC_SPM_MC_CNTL

I didn't find any PM4 packet on GFX9/10 can achieve above goal ....


_____________________________________
Monk Liu|GPU Virtualization Team |AMD
[sig-cloud-gpu]

From: Christian König <[email protected]>
Sent: Monday, April 20, 2020 4:03 PM
To: Liu, Monk <[email protected]>; He, Jacob <[email protected]>; Koenig, 
Christian <[email protected]>
Cc: [email protected]
Subject: Re: why we need to do infinite RLC_SPM register setting during VM flush

I would also prefer to update the SPM VMID register using PM4 packets instead 
of the current handling.

Regards,
Christian.

Am 20.04.20 um 09:50 schrieb Liu, Monk:
I just try to explain what I want to do here, no real patch formalized yet

_____________________________________
Monk Liu|GPU Virtualization Team |AMD
[sig-cloud-gpu]

From: He, Jacob <[email protected]><mailto:[email protected]>
Sent: Monday, April 20, 2020 3:45 PM
To: Liu, Monk <[email protected]><mailto:[email protected]>; Koenig, Christian 
<[email protected]><mailto:[email protected]>
Cc: [email protected]<mailto:[email protected]>
Subject: Re: why we need to do infinite RLC_SPM register setting during VM flush


[AMD Official Use Only - Internal Distribution Only]

Do you miss a file which adds spm_updated to vm structure?
________________________________
From: Liu, Monk <[email protected]<mailto:[email protected]>>
Sent: Monday, April 20, 2020 3:32 PM
To: He, Jacob <[email protected]<mailto:[email protected]>>; Koenig, Christian 
<[email protected]<mailto:[email protected]>>
Cc: [email protected]<mailto:[email protected]> 
<[email protected]<mailto:[email protected]>>
Subject: why we need to do infinite RLC_SPM register setting during VM flush


Hi Jaco & Christian



As titled , check below patch:



commit 10790a09ea584cc832353a5c2a481012e5e31a13

Author: Jacob He <[email protected]<mailto:[email protected]>>

Date:   Fri Feb 28 20:24:41 2020 +0800



    drm/amdgpu: Update SPM_VMID with the job's vmid when application reserves 
the vmid



    SPM access the video memory according to SPM_VMID. It should be updated

    with the job's vmid right before the job is scheduled. SPM_VMID is a

    global resource



    Change-Id: Id3881908960398f87e7c95026a54ff83ff826700

    Signed-off-by: Jacob He <[email protected]<mailto:[email protected]>>

    Reviewed-by: Christian König 
<[email protected]<mailto:[email protected]>>



diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c

index 6e6fc8c..ba2236a 100644

--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c

+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c

@@ -1056,8 +1056,12 @@ int amdgpu_vm_flush(struct amdgpu_ring *ring, struct 
amdgpu_job *job,

        struct dma_fence *fence = NULL;

        bool pasid_mapping_needed = false;

        unsigned patch_offset = 0;

+       bool update_spm_vmid_needed = (job->vm && 
(job->vm->reserved_vmid[vmhub] != NULL));

        int r;



+       if (update_spm_vmid_needed && adev->gfx.rlc.funcs->update_spm_vmid)

+               adev->gfx.rlc.funcs->update_spm_vmid(adev, job->vmid);

+

        if (amdgpu_vmid_had_gpu_reset(adev, id)) {

                gds_switch_needed = true;

                vm_flush_needed = true;



this update_spm_vmid() looks an completely overkill to me, we only need to do 
it once for its VM ...



in SRIOV the register reading/writing for update_spm_vmid() is now carried by 
KIQ thus there is too much burden on KIQ for such unnecessary jobs ...



I want to change it to only do it once per VM, like:



diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c

index 6e6fc8c..ba2236a 100644

--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c

+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c

@@ -1056,8 +1056,12 @@ int amdgpu_vm_flush(struct amdgpu_ring *ring, struct 
amdgpu_job *job,

        struct dma_fence *fence = NULL;

       bool pasid_mapping_needed = false;

        unsigned patch_offset = 0;

+       bool update_spm_vmid_needed = (job->vm && 
(job->vm->reserved_vmid[vmhub] != NULL));

        int r;



+       if (update_spm_vmid_needed && adev->gfx.rlc.funcs->update_spm_vmid &&  
!vm->spm_updated) {

+               adev->gfx.rlc.funcs->update_spm_vmid(adev, job->vmid);

+               vm->spm_updated = true;

+       }



        if (amdgpu_vmid_had_gpu_reset(adev, id)) {

                gds_switch_needed = true;

                vm_flush_needed = true;



what do you think ?



P.S.: the best way is to let GFX ring itself to do the update_spm_vmid() 
instead of let CPU doing it, e.g.: we put more PM4 command in VM-FLUSH packets 
....

But I prefer the simple way first like I demonstrated above

_____________________________________

Monk Liu|GPU Virtualization Team |AMD

[sig-cloud-gpu]





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