[Mesa-users] Fwd: GPU-CPU sync during radeonQueryGetResult

[Brian Paul]

On 07/06/2015 08:09 AM, Vyacheslav Gonakhchyan wrote:
> Hi, everyone.
>
> Trying to understand method radeonQueryGetResult (more broadly GPU-CPU
> sync).
>
> static void radeonQueryGetResult(struct gl_context *ctx, struct
> gl_query_object *q)
> {
>      struct radeon_query_object *query = (struct radeon_query_object *)q;
>          uint32_t *result;
>      int i;
>
>      radeon_print(RADEON_STATE, RADEON_VERBOSE,
>              "%s: query id %d, result %d\n",
>              __func__, query->Base.Id, (int) query->Base.Result);
>
>      radeon_bo_map(query->bo, GL_FALSE);
>          result = query->bo->ptr;
>
>      query->Base.Result = 0;
>      for (i = 0; i < query->curr_offset/sizeof(uint32_t); ++i) {
>          query->Base.Result += LE32_TO_CPU(result[i]);
>          radeon_print(RADEON_STATE, RADEON_TRACE, "result[%d] = %d\n",
> i, LE32_TO_CPU(result[i]));
>      }
>
>      radeon_bo_unmap(query->bo);
> }
>
> I don't know which part is responsible for blocking behavior (waiting
> for response from GPU). I suspect that radeon_bo_map does this magic.
> Can someone point in the right direction?

I suggest that you ask this on the mesa-dev list where the developers 
can comment.

-Brian