ping? On Fri, Mar 15, 2024 at 12:44 PM Alex Deucher <alexdeucher@xxxxxxxxx> wrote: > > On Fri, Mar 15, 2024 at 12:07 PM Alex Deucher <alexander.deucher@xxxxxxx> wrote: > > > > Covers GPU page fault debugging and adds a reference > > to umr. > > > > v2: update client ids to include SQC/G > > > > Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx> > > --- > > Documentation/gpu/amdgpu/debugging.rst | 79 ++++++++++++++++++++++++++ > > Documentation/gpu/amdgpu/index.rst | 1 + > > 2 files changed, 80 insertions(+) > > create mode 100644 Documentation/gpu/amdgpu/debugging.rst > > > > diff --git a/Documentation/gpu/amdgpu/debugging.rst b/Documentation/gpu/amdgpu/debugging.rst > > new file mode 100644 > > index 000000000000..8b7fdcdf1158 > > --- /dev/null > > +++ b/Documentation/gpu/amdgpu/debugging.rst > > @@ -0,0 +1,79 @@ > > +=============== > > + GPU Debugging > > +=============== > > + > > +GPUVM Debugging > > +=============== > > + > > +To aid in debugging GPU virtual memory related problems, the driver supports a > > +number of options module paramters: > > + > > +`vm_fault_stop` - If non-0, halt the GPU memory controller on a GPU page fault. > > + > > +`vm_update_mode` - If non-0, use the CPU to update GPU page tables rather than > > +the GPU. > > + > > + > > +Decoding a GPUVM Page Fault > > +=========================== > > + > > +If you see a GPU page fault in the kernel log, you can decode it to figure > > +out what is going wrong in your application. A page fault in your kernel > > +log may look something like this: > > + > > +:: > > + > > + [gfxhub0] no-retry page fault (src_id:0 ring:24 vmid:3 pasid:32777, for process glxinfo pid 2424 thread glxinfo:cs0 pid 2425) > > + in page starting at address 0x0000800102800000 from IH client 0x1b (UTCL2) > > + VM_L2_PROTECTION_FAULT_STATUS:0x00301030 > > + Faulty UTCL2 client ID: TCP (0x8) > > + MORE_FAULTS: 0x0 > > + WALKER_ERROR: 0x0 > > + PERMISSION_FAULTS: 0x3 > > + MAPPING_ERROR: 0x0 > > + RW: 0x0 > > + > > +First you have the memory hub, gfxhub and mmhub. gfxhub is the memory > > +hub used for graphics, compute, and sdma on some chips. mmhub is the > > +memory hub used for multi-media and sdma on some chips. > > + > > +Next you have the vmid and pasid. If the vmid is 0, this fault was likely > > +caused by the kernel driver or firmware. If the vmid is non-0, it is generally > > +a fault in a user application. The pasid is used to link a vmid to a system > > +process id. If the process is active when the fault happens, the process > > +information will be printed. > > + > > +The GPU virtual address that caused the fault comes next. > > + > > +The client ID indicates the GPU block that caused the fault. > > +Some common client IDs: > > + > > +- CB/DB: The color/depth backend of the graphics pipe > > +- CPF: Command Processor Frontend > > +- CPC: Command Processor Compute > > +- CPG: Command Processor Graphics > > +- TCP/SQC/SQG: Shaders > > +- SDMA: SDMA engines > > +- VCN: Video encode/decode engines > > +- JPEG: JPEG engines > > + > > +PERMISSION_FAULTS describe what faults were encountered: > > + > > +- bit 0: the PTE was not valid > > +- bit 1: the PTE read bit was not set > > +- bit 2: the PTE write bit was not set > > +- bit 3: the PTE execute bit was not set > > + > > +Finally, RW, indicates whether the access was a read (0) or a write (1). > > + > > +In the example above, a shader (cliend id = TCP) generated a read (RW = 0x0) to > > +an invalid page (PERMISSION_FAULTS = 0x3) at GPU virtual address > > +0x0000800102800000. The user can then inspect can then inspect their shader > > removed the duplicated text above locally. > > Alex > > > +code and resource descriptor state to determine what caused the GPU page fault. > > + > > +UMR > > +=== > > + > > +`umr <https://gitlab.freedesktop.org/tomstdenis/umr>`_ is a general purpose > > +GPU debugging and diagnostics tool. Please see the umr documentation for > > +more information about its capabilities. > > diff --git a/Documentation/gpu/amdgpu/index.rst b/Documentation/gpu/amdgpu/index.rst > > index 912e699fd373..847e04924030 100644 > > --- a/Documentation/gpu/amdgpu/index.rst > > +++ b/Documentation/gpu/amdgpu/index.rst > > @@ -15,4 +15,5 @@ Next (GCN), Radeon DNA (RDNA), and Compute DNA (CDNA) architectures. > > ras > > thermal > > driver-misc > > + debugging > > amdgpu-glossary > > -- > > 2.44.0 > >
