Re: [PATCH] drm/amdgpu: Derive RLC SPM xcc from GFXHUB

["Lazar, Lijo" <lijo.lazar@amd.com>]

On 25-Sep-26 4:04 PM, Tvrtko Ursulin wrote:
> 
> On 25/09/2026 10:37, Lijo Lazar wrote:
>> RLC SPM is updated for GFX subsystem related performance counters. Only
>> jobs on rings that use GFX subsystem need to be updated. Some rings like
>> SDMA could be inside/outside of GFX subsytem based on SOC. Identify the
>> rings using GFXHUB assignment and use hub id assigned to find the right
>> GC rather than relying on xcc id. xcc id may not be necessarily assigned
>> properly for all rings.
> 
> I don't know the hardware well enough to review or be certain of what I 
> will ask, but if you remember the "kitten dies" meme it often comes to 
> my mind that "every time amdgpu repeatedly walks a list of everything to 
> find something at runtime a kitten dies". :)
> 
> On a serious note, question I have following the statement from the 
> commit message that xcc id is not always correct for all rings is, would 
> it be feasible to make it correct? At ring init time I mean. And so 
> avoid having to repeatedly look for it.
> 

Having to associate xcc_id with every ring (for ex: vcn/jpeg) is 
overloading it with too many things.

This is one of the changes in another set to remove xcc_id and keep a 
dedicated ip_inst. Then realized that a sdma job also could trigger a 
spm vmid update, then using ring->ip_inst doesn't work (even now, xcc id 
for sdma ring is not assigned properly).

That said, so far for gfxhub, xcc_id = ring->vmhub holds. The loop is 
only to appear it technically good. Also, max xcc = 8 (so far).

Thanks,
Lijo


> Regards,
> 
> Tvrtko
> 
>> Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
>> ---
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c  |  2 +-
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_rlc.c | 31 +++++++++++++++++++++++++
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_rlc.h |  2 ++
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c  |  2 +-
>>   4 files changed, 35 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c b/drivers/gpu/drm/ 
>> amd/amdgpu/amdgpu_ib.c
>> index 0f8b097001e3..6ea73ef6e672 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
>> @@ -212,7 +212,7 @@ int amdgpu_ib_schedule(struct amdgpu_ring *ring, 
>> struct amdgpu_job *job,
>>           amdgpu_ring_emit_pipeline_sync(ring);
>>       if (emit_spm_needed)
>> -        adev->gfx.rlc.funcs->update_spm_vmid(adev, ring->xcc_id, 
>> ring, job->vmid);
>> +        amdgpu_gfx_rlc_update_spm(adev, ring, job->vmid);
>>       if (emit_gds_needed)
>>           amdgpu_ring_emit_gds_switch(ring, job->vmid, job->gds_base,
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_rlc.c b/drivers/gpu/ 
>> drm/amd/amdgpu/amdgpu_rlc.c
>> index 002fae3c380e..f791e1bcbf17 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_rlc.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_rlc.c
>> @@ -27,6 +27,37 @@
>>   #include "amdgpu_gfx.h"
>>   #include "amdgpu_rlc.h"
>> +/**
>> + * amdgpu_gfx_rlc_update_spm - update RLC SPM VMID
>> + *
>> + * @adev: amdgpu_device pointer
>> + * @ring: ring the VMID got assigned to
>> + * @vmid: VMID to program
>> + *
>> + * RLC SPM counters are used only for GFX and GFX Cache subsystem. 
>> Only jobs submitted to
>> + * rings in GFX subsystem need to update RLC SPM counters. Derive 
>> xcc_id from ring->vm_hub.
>> + */
>> +void amdgpu_gfx_rlc_update_spm(struct amdgpu_device *adev,
>> +                   struct amdgpu_ring *ring, unsigned int vmid)
>> +{
>> +    int xcc_id, num_xcc;
>> +
>> +    if (!adev->gfx.rlc.funcs->update_spm_vmid || !ring)
>> +        return;
>> +
>> +    if (!AMDGPU_IS_GFXHUB(ring->vm_hub))
>> +        return;
>> +
>> +    num_xcc = NUM_XCC(adev->gfx.xcc_mask);
>> +    for (xcc_id = 0; xcc_id < num_xcc; xcc_id++) {
>> +        if (AMDGPU_GFXHUB(xcc_id) == ring->vm_hub) {
>> +            adev->gfx.rlc.funcs->update_spm_vmid(adev, xcc_id, ring,
>> +                                 vmid);
>> +            return;
>> +        }
>> +    }
>> +}
>> +
>>   /**
>>    * amdgpu_gfx_rlc_enter_safe_mode - Set RLC into safe mode
>>    *
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_rlc.h b/drivers/gpu/ 
>> drm/amd/amdgpu/amdgpu_rlc.h
>> index 959d60c90dcd..1410954da5a6 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_rlc.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_rlc.h
>> @@ -370,6 +370,8 @@ struct amdgpu_rlc {
>>       struct amdgpu_rlcg_reg_access_ctrl 
>> reg_access_ctrl[AMDGPU_MAX_RLC_INSTANCES];
>>   };
>> +void amdgpu_gfx_rlc_update_spm(struct amdgpu_device *adev,
>> +                   struct amdgpu_ring *ring, unsigned int vmid);
>>   void amdgpu_gfx_rlc_enter_safe_mode(struct amdgpu_device *adev, int 
>> xcc_id);
>>   void amdgpu_gfx_rlc_exit_safe_mode(struct amdgpu_device *adev, int 
>> xcc_id);
>>   int amdgpu_gfx_rlc_init_sr(struct amdgpu_device *adev, u32 dws);
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/ 
>> amd/amdgpu/amdgpu_vm.c
>> index 29a66e39f3d6..dc8f85176b8b 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>> @@ -865,7 +865,7 @@ void amdgpu_vm_flush(struct amdgpu_ring *ring, 
>> struct amdgpu_job *job,
>>           amdgpu_gmc_emit_pasid_mapping(ring, job->vmid, job->pasid);
>>       if (spm_update_needed)
>> -        adev->gfx.rlc.funcs->update_spm_vmid(adev, ring->xcc_id, 
>> ring, job->vmid);
>> +        amdgpu_gfx_rlc_update_spm(adev, ring, job->vmid);
>>       if (gds_switch_needed)
>>           amdgpu_ring_emit_gds_switch(ring, job->vmid, job->gds_base,
>