On Friday, September 25, 2015 11:06:32 AM Matt Turner wrote: > On Fri, Sep 25, 2015 at 10:47 AM, Kenneth Graunke <kenn...@whitecape.org> > wrote: > > With static vertex counts, the final EOT write doesn't actually write > > any data - it's just there to end the thread. Typically, the last > > thing before ending the thread will be an EmitVertex() call, resulting > > in a URB write. We can just set EOT on that. > > > > Note that this isn't always possible - there might be an intervening > > SSBO write/image store, or the URB write may have been in a loop. > > > > shader-db statistics for geometry shaders only: > > > > total instructions in shared programs: 3173 -> 3149 (-0.76%) > > instructions in affected programs: 176 -> 152 (-13.64%) > > total loops in shared programs: 1 -> 1 (0.00%) > > I've been stripping out lines like this, or "HURT: 0" from my stats > when they don't really indicate anything that wasn't expected. > > I can patch report.py to simply not print them in those cases if we want.
Yeah, I meant to take that out...I just missed it here. Will do.
>
> > helped: 8
> >
> > Signed-off-by: Kenneth Graunke <kenn...@whitecape.org>
> > ---
> > src/mesa/drivers/dri/i965/brw_vec4_gs_visitor.cpp | 15 +++++++++++++++
> > 1 file changed, 15 insertions(+)
> >
> > This requires my previous series. We could extend this to Gen7 as well...
> > we'd just need to move the GS_OPCODE_SET_VERTEX_COUNT above the earlier
> > URB write so the message header bits get set. I just haven't pulled out
> > the older laptop. This didn't seem to help performance in Gl32GSCloth.
> > Maybe a tiny bit, but not easily measured.
> >
> > diff --git a/src/mesa/drivers/dri/i965/brw_vec4_gs_visitor.cpp
> > b/src/mesa/drivers/dri/i965/brw_vec4_gs_visitor.cpp
> > index acf0501..d2edc57 100644
> > --- a/src/mesa/drivers/dri/i965/brw_vec4_gs_visitor.cpp
> > +++ b/src/mesa/drivers/dri/i965/brw_vec4_gs_visitor.cpp
> > @@ -236,6 +236,21 @@ vec4_gs_visitor::emit_thread_end()
> >
> > bool static_vertex_count = c->prog_data.static_vertex_count != -1;
> >
> > + /* If the previous instruction was a URB write, we don't need to issue
> > + * a second one - we can just set the EOT bit on the previous write.
> > + *
> > + * Skip this on Gen8+ unless there's a static vertex count, as we also
> > + * need to write the vertex count out, and combining the two may not be
> > + * possible (or at least not straightforward).
> > + */
> > + vec4_instruction *last = (vec4_instruction *) instructions.get_tail();
> > + if (last && last->opcode == GS_OPCODE_URB_WRITE &&
> > + !(INTEL_DEBUG & DEBUG_SHADER_TIME) &&
> > + devinfo->gen >= 8 && static_vertex_count) {
> > + last->urb_write_flags = BRW_URB_WRITE_EOT | last->urb_write_flags;
>
> The operand ordering on the RHS made me thing something odd was going
> on. Change this to...?
>
> last->urb_write_flags |= BRW_URB_WRITE_EOT;
>
> With that,
>
> Reviewed-by: Matt Turner <matts...@gmail.com>
That's illegal due to C++ enum disasters:
brw_vec4_gs_visitor.cpp:250:29: error: invalid conversion from ‘int’ to
‘brw_urb_write_flags’ [-fpermissive]
last->urb_write_flags |= BRW_URB_WRITE_EOT;
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