[PATCH] drm/amd/amdgpu: Add tracepoint for DMA page mapping

[Christian König]

Am 01.08.2017 um 14:29 schrieb Tom St Denis:
> On 01/08/17 07:55 AM, Christian König wrote:
>> Am 01.08.2017 um 13:51 schrieb Tom St Denis:
>>> This helps map DMA addresses back to physical addresses.
>>>
>>> Signed-off-by: Tom St Denis <tom.stdenis at amd.com>
>>> ---
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h | 28 
>>> ++++++++++++++++++++++++++++
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c   |  8 ++++++++
>>>   2 files changed, 36 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h 
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h
>>> index 509f7a63d40c..5b2bb28da504 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h
>>> @@ -14,6 +14,34 @@
>>>   #define AMDGPU_JOB_GET_TIMELINE_NAME(job) \
>>> job->base.s_fence->finished.ops->get_timeline_name(&job->base.s_fence->finished) 
>>>
>>> +TRACE_EVENT(amdgpu_ttm_tt_populate,
>>> +        TP_PROTO(uint16_t domain, uint8_t bus, uint8_t slot, 
>>> uint8_t func, uint64_t dma_address, uint64_t phys_address),
>>> +        TP_ARGS(domain, bus, slot, func, dma_address, phys_address),
>>> +        TP_STRUCT__entry(
>>> +                __field(uint16_t, domain)
>>> +                __field(uint8_t, bus)
>>> +                __field(uint8_t, slot)
>>> +                __field(uint8_t, func)
>>> +                __field(uint64_t, dma)
>>> +                __field(uint64_t, phys)
>>> +                ),
>>
>> Better just give adev here and extract the values during the fast 
>> assign.
>
> Easy enough, I've done this now.
>
>>
>>> +        TP_fast_assign(
>>> +               __entry->domain = domain;
>>> +               __entry->bus = bus;
>>> +               __entry->slot = slot;
>>> +               __entry->func = func;
>>> +               __entry->dma = dma_address;
>>> +               __entry->phys = phys_address;
>>> +               ),
>>> +        TP_printk("%04x:%02x:%02x.%x: 0x%llx => 0x%llx",
>>> +              (unsigned)__entry->domain,
>>> +              (unsigned)__entry->bus,
>>> +              (unsigned)__entry->slot,
>>> +              (unsigned)__entry->func,
>>> +              (unsigned long long)__entry->dma,
>>> +              (unsigned long long)__entry->phys)
>>> +);
>>> +
>>>   TRACE_EVENT(amdgpu_mm_rreg,
>>>           TP_PROTO(unsigned did, uint32_t reg, uint32_t value),
>>>           TP_ARGS(did, reg, value),
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c 
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>>> index 8da59d212b3b..1cf274603476 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>>> @@ -43,6 +43,7 @@
>>>   #include <linux/pagemap.h>
>>>   #include <linux/debugfs.h>
>>>   #include "amdgpu.h"
>>> +#include "amdgpu_trace.h"
>>>   #include "bif/bif_4_1_d.h"
>>>   #define DRM_FILE_PAGE_OFFSET (0x100000000ULL >> PAGE_SHIFT)
>>> @@ -944,6 +945,13 @@ static int amdgpu_ttm_tt_populate(struct ttm_tt 
>>> *ttm)
>>>               ttm_pool_unpopulate(ttm);
>>>               return -EFAULT;
>>>           }
>>> +        trace_amdgpu_ttm_tt_populate(
>>> +            pci_domain_nr(adev->pdev->bus),
>>> +            adev->pdev->bus->number,
>>> +            PCI_SLOT(adev->pdev->devfn),
>>> +            PCI_FUNC(adev->pdev->devfn),
>>> +            gtt->ttm.dma_address[i],
>>> +            page_to_phys(ttm->pages[i]));
>>
>> Please add that tracing for the dma pool path as well.
>>
>> With that fixed the change looks good to me,
>> Christian.
>
> Unsure what you mean here.  The ttm_pool_populate() seems to be 
> preparing the page list to back the request.

You need to cover multiple code path here:
1. The one you currently implemented which uses ttm_dma_populate() and 
pci_map_page().
2. The one using ttm_dma_populate().
3. The one using drm_prime_sg_to_page_addr_arrays() a bit above for 
imported BOs.
4. The in amdgpu_ttm_tt_pin_userptr() which uses dma_map_sg() for userptrs.

Basically all just take gtt->ttm.ttm.pages and fill gtt->ttm.dma_address.

I suggest to add a helper you can call to trace all pages->dma_address 
mappings inside a ttm.

Regards,
Christian.

>
> Tom
> _______________________________________________
> amd-gfx mailing list
> amd-gfx at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/amd-gfx