[Mesa-dev] [PATCH 02/12] i965/urb: Trigger upload_urb on NEW_BLORP

[Kenneth Graunke]

On Monday, June 26, 2017 4:22:35 PM PDT Ian Romanick wrote:
> From: Jason Ekstrand <jason.ekstrand at intel.com>
> 
> It's a bit rare, but blorp can trigger a urb reconfiguration.  When that
> happens, we need to re-upload the URB config.  Fortunately, this isn't as
> bad as it looks because gen7_upload_urb will not re-emit the packet if it
> would end up being a no-op so this doesn't mean that running blorp always
> triggers a URB reconfig.
> 
> v2 (idr): Sort BRW_NEW_ tokens to match brw_recalculate_urb_fence and
> gen6_urb.
> 
> v3 (idr): Don't whack BRW_NEW_URB_SIZE in blorp.  Suggested by Jason.
> ---
>  src/mesa/drivers/dri/i965/gen7_urb.c        | 3 ++-
>  src/mesa/drivers/dri/i965/genX_blorp_exec.c | 2 --
>  2 files changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/src/mesa/drivers/dri/i965/gen7_urb.c b/src/mesa/drivers/dri/i965/gen7_urb.c
> index 525c9c4..c4b479c 100644
> --- a/src/mesa/drivers/dri/i965/gen7_urb.c
> +++ b/src/mesa/drivers/dri/i965/gen7_urb.c
> @@ -236,7 +236,8 @@ gen7_upload_urb(struct brw_context *brw, unsigned vs_size,
>  const struct brw_tracked_state gen7_urb = {
>     .dirty = {
>        .mesa = 0,
> -      .brw = BRW_NEW_CONTEXT |
> +      .brw = BRW_NEW_BLORP |
> +             BRW_NEW_CONTEXT |
>               BRW_NEW_URB_SIZE |
>               BRW_NEW_GS_PROG_DATA |
>               BRW_NEW_TCS_PROG_DATA |
> diff --git a/src/mesa/drivers/dri/i965/genX_blorp_exec.c b/src/mesa/drivers/dri/i965/genX_blorp_exec.c
> index 8fd17fb..af3d609 100644
> --- a/src/mesa/drivers/dri/i965/genX_blorp_exec.c
> +++ b/src/mesa/drivers/dri/i965/genX_blorp_exec.c
> @@ -183,8 +183,6 @@ blorp_emit_urb_config(struct blorp_batch *batch,
>         brw->urb.vsize >= vs_entry_size)
>        return;
>  
> -   brw->ctx.NewDriverState |= BRW_NEW_URB_SIZE;
> -
>     gen7_upload_urb(brw, vs_entry_size, false, false);
>  #elif GEN_GEN == 6
>     gen6_upload_urb(brw, vs_entry_size, false, 0);
> 

The commit message is a bit confusing.  It makes it sound like we were
failing to re-emit 3DSTATE_URB_* from the main drawing path after BLORP
trashed it.  However, the brw->ctx.NewDriverState |= BRW_NEW_URB_SIZE
line that you deleted here guaranteed that it would happen.

The real benefit appears to be that flagging BRW_NEW_URB_SIZE ("the
total size of the URB portion of the L3 cache has changed") causes
BLORP to think it needs to re-configure it again, so say, back-to-back
BLORP operations would configure it every time.

Using BRW_NEW_BLORP is definitely better - that's what it's there for.

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