[PATCH] drm/amdgpu: trace amdgpu_job fence details

[Andres Rodriguez]

On 2017-02-23 02:46 PM, Andres Rodriguez wrote:
>
>
> On 2017-02-23 03:20 AM, Christian König wrote:
>> Am 23.02.2017 um 00:47 schrieb Andres Rodriguez:
>>> This trace is intended to provide the required information to associate
>>> the completion of an amdgpu_job with its corresponding dma_fence_*
>>> tracepoints.
>>>
>>> Signed-off-by: Andres Rodriguez <andresx7 at gmail.com>
>>> ---
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_job.c   |  2 ++
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h | 22 ++++++++++++++++++++++
>>>   2 files changed, 24 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c 
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
>>> index 86a1242..84a04e4 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
>>> @@ -177,6 +177,8 @@ static struct dma_fence *amdgpu_job_run(struct 
>>> amd_sched_job *sched_job)
>>>       /* if gpu reset, hw fence will be replaced here */
>>>       dma_fence_put(job->fence);
>>>       job->fence = dma_fence_get(fence);
>>> +    trace_amdgpu_job_attach_fence(job);
>>> +
>>>       amdgpu_job_free_resources(job);
>>>       return fence;
>>>   }
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h 
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h
>>> index a18ae1e..0a61ed9 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h
>>> @@ -147,6 +147,28 @@ TRACE_EVENT(amdgpu_sched_run_job,
>>>                 __entry->fence, __entry->ring_name, __entry->num_ibs)
>>>   );
>>>   +TRACE_EVENT(amdgpu_job_attach_fence,
>>> +        TP_PROTO(struct amdgpu_job *job),
>>> +        TP_ARGS(job),
>>> +        TP_STRUCT__entry(
>>> +                 __field(struct amdgpu_device *, adev)
>>> +                 __field(struct amd_sched_job *, sched_job)
>>
>> Neither add adev nor sched_job pointer to your trace point.
> Would it be okay then to grab a reference to the scheduler fence in 
> amdgpu_job_run and print the sched fence pointer here?
>
> That would give us enough info to correlate other trace points like 
> amdgpu_cs_ioctl aor amdgpu_sched_run_job to the respective dma_fence 
> tracepoints.
>
>
>>
>> The adev pointer is completely meaningless in the logs and the 
>> scheduler job might already be freed when the printk is called.
Hey Christian,

I was just double checking the lifetime of the scheduler job, and it 
should still be valid during amdgpu_job_run. The lifetime of the job is 
tied to the scheduler finished fence which won't be signaled until 
amdgpu_job_run finishes even if the HW fence has signaled.

This is assuming that the trace printks are synchronous.

So I think printing the job and dropping adev should be okay if the 
above holds true, unless I'm missing something else.

>>
>> Just checked the source and a couple of other trace points get this 
>> horrible wrong as well, so that isn't your fault. Going to put it on 
>> my todo to fix those.
>>
>> Regards,
>> Christian.
>>
>>> +                 __string(timeline, 
>>> job->fence->ops->get_timeline_name(job->fence))
>>> +                 __field(unsigned int, context)
>>> +                 __field(unsigned int, seqno)
>>> +                 ),
>>> +
>>> +        TP_fast_assign(
>>> +               __entry->adev = job->adev;
>>> +               __entry->sched_job = &job->base;
>>> +               __assign_str(timeline, 
>>> job->fence->ops->get_timeline_name(job->fence))
>>> +               __entry->context = job->fence->context;
>>> +               __entry->seqno = job->fence->seqno;
>>> +               ),
>>> +        TP_printk("adev=%p, sched_job=%p, timeline:%s, context:%u, 
>>> seqno:%u",
>>> +              __entry->adev, __entry->sched_job,
>>> +              __get_str(timeline), __entry->context, __entry->seqno)
>>> +);
>>>     TRACE_EVENT(amdgpu_vm_grab_id,
>>>           TP_PROTO(struct amdgpu_vm *vm, int ring, struct amdgpu_job 
>>> *job),
>>
>>
>