[PATCH v3 1/8] tracing, dma-buf: add a trace_dma_fence_sync_to event

[Christian König]

Am 16.02.24 um 16:09 schrieb Pierre-Eric Pelloux-Prayer:
> This new event can be used to trace where a given dma_fence is added
> as a dependency of some other work.
>
> I plan to use it in amdgpu.
>
> Signed-off-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer at amd.com>
> ---
>   drivers/dma-buf/dma-fence.c      |  1 +
>   include/trace/events/dma_fence.h | 27 +++++++++++++++++++++++++++
>   2 files changed, 28 insertions(+)
>
> diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
> index 0393a9bba3a8..e7276c043984 100644
> --- a/drivers/dma-buf/dma-fence.c
> +++ b/drivers/dma-buf/dma-fence.c
> @@ -23,6 +23,7 @@
>   EXPORT_TRACEPOINT_SYMBOL(dma_fence_emit);
>   EXPORT_TRACEPOINT_SYMBOL(dma_fence_enable_signal);
>   EXPORT_TRACEPOINT_SYMBOL(dma_fence_signaled);
> +EXPORT_TRACEPOINT_SYMBOL(dma_fence_used_as_dependency);
>   
>   static DEFINE_SPINLOCK(dma_fence_stub_lock);
>   static struct dma_fence dma_fence_stub;
> diff --git a/include/trace/events/dma_fence.h b/include/trace/events/dma_fence.h
> index 3963e79ca7b4..5a5d272031ce 100644
> --- a/include/trace/events/dma_fence.h
> +++ b/include/trace/events/dma_fence.h
> @@ -83,6 +83,33 @@ DEFINE_EVENT(dma_fence, dma_fence_wait_end,
>   	TP_ARGS(fence)
>   );
>   
> +TRACE_EVENT(dma_fence_used_as_dependency,
> +
> +	TP_PROTO(struct dma_fence *fence, const char *reason),
> +
> +	TP_ARGS(fence, reason),
> +
> +	TP_STRUCT__entry(
> +		__string(driver, fence->ops->get_driver_name(fence))
> +		__string(timeline, fence->ops->get_timeline_name(fence))
> +		__field(unsigned int, context)
> +		__field(unsigned int, seqno)

I noted it before that this needs to be an u64 and not unsigned int. 
Otherwise we will lose the higher 32bits.

The existing trace points have that bug as well, so you might also want 
to provide a patch to fix this.

Christian.

> +		__string(reason, reason)
> +	),
> +
> +	TP_fast_assign(
> +		__assign_str(driver, fence->ops->get_driver_name(fence));
> +		__assign_str(timeline, fence->ops->get_timeline_name(fence));
> +		__entry->context = fence->context;
> +		__entry->seqno = fence->seqno;
> +		__assign_str(reason, reason);
> +	),
> +
> +	TP_printk("driver=%s timeline=%s context=%u seqno=%u reason=%s",
> +		  __get_str(driver), __get_str(timeline), __entry->context,
> +		  __entry->seqno, __get_str(reason))
> +);
> +
>   #endif /*  _TRACE_DMA_FENCE_H */
>   
>   /* This part must be outside protection */