[Mesa-dev] A question about order of st_update_*p

[Marek Olšák]

The order of GPU execution doesn't matter here.

M.

On Fri., Jul. 26, 2019, 16:11 Lepton Wu, <lepton at chromium.org> wrote:

> I am confused, for example,  according to:
>
> https://www.khronos.org/opengl/wiki/Geometry_Shader, it come after
> Vertex shader, that mean, it depends on vertex shader, right?
> So st_update_gp should be after st_update_vp, but now it is in the
> front of st_update_vp.
>
> On Fri, Jul 26, 2019 at 1:07 PM Marek Olšák <maraeo at gmail.com> wrote:
> >
> >
> >
> > On Fri., Jul. 26, 2019, 15:58 Lepton Wu, <lepton at chromium.org> wrote:
> >>
> >> If shader A depends on shader B,  should we put st_update_shaderB  in
> >> front of st_update_shaderA?
> >
> >
> > That's the current order. The order of GPU execution doesn't matter.
> >
> > M.
> >
> >>
> >> Now the order looks like reversed...
> >>
> >> On Fri, Jul 26, 2019 at 12:34 PM Marek Olšák <maraeo at gmail.com> wrote:
> >> >
> >> > The order shouldn't matter, but there can be a reason behind it, e.g.
> if a shader depends on the update of the following shader.
> >> >
> >> > Marek
> >> >
> >> > On Wed, Jul 24, 2019 at 7:19 PM Lepton Wu <lepton at chromium.org>
> wrote:
> >> >>
> >> >> In src/mesa/state_tracker/st_atom_list.h,
> >> >>
> >> >> Now it's this order:
> >> >>
> >> >> ST_STATE(ST_NEW_FS_STATE, st_update_fp)
> >> >> ST_STATE(ST_NEW_GS_STATE, st_update_gp)
> >> >> ST_STATE(ST_NEW_TES_STATE, st_update_tep)
> >> >> ST_STATE(ST_NEW_TCS_STATE, st_update_tcp)
> >> >> ST_STATE(ST_NEW_VS_STATE, st_update_vp)
> >> >>
> >> >> While code in
> >> >> src/mesa/state_tracker/st_atom.c:
> >> >>
> >> >> while (dirty_lo)
> >> >>      update_functions[u_bit_scan(&dirty_lo)](st);
> >> >>
> >> >> That means if will call st_update_fp first and then st_update_gp...
> etc.
> >> >>
> >> >> But this is inconsistent with opengl pipeline: should we reverse the
> >> >> order here or I missed something?
> >> >>
> >> >> Background:
> >> >>
> >> >> https://gitlab.freedesktop.org/virgl/virglrenderer/issues/114
> >> >> _______________________________________________
> >> >> mesa-dev mailing list
> >> >> mesa-dev at lists.freedesktop.org
> >> >> https://lists.freedesktop.org/mailman/listinfo/mesa-dev
>
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