Re: Why has to offer "/dev/drv/render128" fd when running ROCm demo?

Christian König <ckoenig.leichtzumerken@xxxxxxxxx> · Wed, 6 Mar 2024 14:42:15 +0100



    Hi Zicao,

    
    that won't work any more the render Node is mandatory for correct
    ROCm operation by now.

    
    Regards,

    Christian.

    
    Am 06.03.24 um 06:25 schrieb 曹子龙:

    
        Hi felix:
           Thanks for your kindly help.
        

        i still has a question, if on a
          pure-compute platform, which has no /dev/dri/render node, but
          only with a single /dev/kfd node, how the compue scenario
          works since that wei have no "render" fd exists?

        
        is such platfom(without render node)
          exists? 
        

         thanks for your kindly help.!
        

        BRs
        zlcao.
        

        At 2024-03-06 04:43:30, "Kuehling, Felix"
          <Felix.Kuehling@xxxxxxx> wrote:
        
          
                [AMD Official Use Only - General]

              
                  I
                      already answered this question in a reply to
                      another email that was addressed to me:
                   
                  The
                      render nodes are used for CPU mapping of VRAM with
                      mmap calls and an offset that identifies the BO.
                      The render node also creates the GPU virtual
                      address space that is used by KFD to create the
                      GPU memory mappings. Applications that use both
                      graphics and compute can share the same GPU
                      virtual address space in this way.
                   
                  Zlcao,
                      in the future, this type of question may be better
                      addressed to a mailing list such as
                      amd-gfx@xxxxxxxxxxxxxxxxxxxxx, instead of writing
                      separately to different maintainers.
                   
                  Regards,

                        Felix
                   
                   
                      From:
                          Deucher, Alexander
                          <Alexander.Deucher@xxxxxxx>
                          

                          Sent: Tuesday, March 5, 2024 3:17 PM

                          To: 曹子龙
                          <gainerying@xxxxxxx>; Kuehling, Felix
                          <Felix.Kuehling@xxxxxxx>; Yat Sin, David
                          <David.YatSin@xxxxxxx>

                          Subject: Re: Why has to offer
                          "/dev/drv/render128" fd when running ROCm
                          demo?
                    
                  
                  [AMD
                      Official Use Only - General]
                   
                  
                      + Felix,
                          David to comment.
                    
                    
                      From:
                        曹子龙
                          <gainerying@xxxxxxx>

                          Sent: Tuesday, March 5, 2024 8:46 AM

                          To: Deucher, Alexander <Alexander.Deucher@xxxxxxx>

                          Subject: Why has to offer
                          "/dev/drv/render128" fd when running ROCm
                          demo?
                        
                      
                        Hi
                            alexander.:
                        
                          
                                    sorry for bother. but i really need
                                some help to deal with my puzzle. 
                          
                          
                            i
                                am a freshman to AMD GPU Driver, NOW i
                                am trying to write a simple demo to use
                                "/dev/kfd" and do some  vram alloc/free
                                tests,  but i found you must do the
                                right "AMDKFD_IOC_ACQUIRE_VM" ioctl
                                comamnd before you try GPU to do vram
                                allocation and other things.  from the
                                kfd driver code,the pre-condition to do
                                the right "AMDKFD_IOC_ACQUIRE_VM" is to
                                offer a "/dev/drv/render128" fd  to the
                                parameters.
                          
                          
                            so,
                                why need to do this? kfd is used for
                                compute, but "/dev/dri/render128" is
                                specify to gfx usaged, why must open the
                                "/dev/dri/render128" during the KFD
                                compute scenario?
                          
                          
                            thanks
                                for your kindly help!
                          
                          
                            BRs
                          
                          
                            zlcao.