[Mesa-dev] [PATCH] i965: Always enable VF statistics

[Kenneth Graunke]

On Wednesday, November 12, 2014 06:54:31 PM Ben Widawsky wrote:
> Every other unit in the geometry pipeline automatically enables
> statistics gathering. This part of the pipe has been controlled by the
> DEBUG_STATS variable, but this is asymmetric. This dates back to the
> original implementation, and I am not sure if there is a reason for it.
> 
> I need access to these stats to implement ARB_pipeline_statistics_query.
> 
> Eric wrote it, and Ken touched it last. Do you have any opposition?
> 
> Cc: Eric Anholt <eric at anholt.net>
> Cc: Kenneth Graunke <kenneth at whitecape.org>
> Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
> ---
>  src/mesa/drivers/dri/i965/brw_misc_state.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/src/mesa/drivers/dri/i965/brw_misc_state.c 
b/src/mesa/drivers/dri/i965/brw_misc_state.c
> index 99fcddc..2c40814 100644
> --- a/src/mesa/drivers/dri/i965/brw_misc_state.c
> +++ b/src/mesa/drivers/dri/i965/brw_misc_state.c
> @@ -929,8 +929,7 @@ brw_upload_invariant_state(struct brw_context *brw)
>     const uint32_t _3DSTATE_VF_STATISTICS =
>        is_965 ? GEN4_3DSTATE_VF_STATISTICS : GM45_3DSTATE_VF_STATISTICS;
>     BEGIN_BATCH(1);
> -   OUT_BATCH(_3DSTATE_VF_STATISTICS << 16 |
> -	     (unlikely(INTEL_DEBUG & DEBUG_STATS) ? 1 : 0));
> +   OUT_BATCH(_3DSTATE_VF_STATISTICS << 16 | 1);
>     ADVANCE_BATCH();
>  }

My only complaint about this patch is that it doesn't go far enough.  I'm 100% 
for removing DEBUG_STATS completely.  I've never seen any performance penalty 
for enabling statistics.  I think we should leave them on except when there's 
some reason to turn them off (i.e. brw->meta_in_progress flag in the clipper, 
which prevents us from counting i.e. glClear).

Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>
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