[Mesa-dev] [PATCH] gallium/include/pipe: Added interface for atomic counter buffers in pipe
Ilia Mirkin
imirkin at alum.mit.edu
Mon Nov 17 11:43:00 PST 2014
The issue with STORE isn't whether it's necessary (it is!), but the
exact semantics of the TGSI opcode. The way I have it in my patch
right now is that it doesn't have a destination, which upsets the dead
code removal logic in st_glsl_to_tgsi greatly. For now I've just
commented it out, but that's not a long-term solution. See current
docs at http://gallium.readthedocs.org/en/latest/tgsi.html#opcode-STORE
-- I've changed it by moving the RES[] to the end, which is consistent
with how e.g. TEX works.
On Mon, Nov 17, 2014 at 2:39 PM, Aditya Avinash
<adityaavinash1 at gmail.com> wrote:
> Hi,
> I agree with the solution. Considering "images" as "buffers" or "buffers" as
> "images" (as they are operated inside shaders but not texture units) makes
> sense. I think we can make atomic buffers as a part of
> ARB_shader_image_load_store. Because, images are 2D array of buffers with
> atomic operations run on them.
>
> You have mentioned in our previous conversation about the un-necessity of
> store. The spec for ARB_shader_image_load_store says imageStore(). If we are
> implementing the same for atomics, then we have to use store for it too.
>
> Thank you!!
>
> On Mon, Nov 17, 2014 at 11:28 AM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
>>
>> Because shader resources were already specified as pipe_surfaces (in
>> the existing, albeit presently unused API). A pipe_surface is a
>> wrapper around a resource that specifies what "view" of the resource
>> should be writable, and attaches an optional format to that resource.
>> Normally pipe_surfaces are used for render targets, but it applies
>> just as well here. It applies especially well with a view towards
>> ARB_shader_image_load_store.
>>
>> It's conceivable to make a totally separate thing for atomic buffers,
>> but there's no good reason to -- they will have to be handled in
>> essentially the same way as regular "image" surfaces will for
>> ARB_shader_image_load_store.
>>
>> Cheers,
>>
>> -ilia
>>
>> On Mon, Nov 17, 2014 at 11:19 AM, Aditya Avinash
>> <adityaavinash1 at gmail.com> wrote:
>> > Hi,
>> > I am having difficulty in understanding why you implemented pipe_surface
>> > in
>> > st_atom_atomicbuf.c.
>> >
>> > On Mon, Nov 17, 2014 at 2:24 AM, Aditya Avinash
>> > <adityaavinash1 at gmail.com>
>> > wrote:
>> >>
>> >> Hi,
>> >>
>> >> On Sunday, November 16, 2014, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
>> >>>
>> >>> The direction I went in was by adapting the shader resources interface
>> >>> for this. I believe it will be possible to use for
>> >>> shader_image_load_store as well.
>> >>
>> >>
>> >> I asked some questions on mailing list about the implementation. I took
>> >> the same path as uniform buffers. But, I realized that it's not
>> >> efficient to
>> >> do that.
>> >>
>> >>>
>> >>> See https://github.com/imirkin/mesa/commits/atomic
>> >>>
>> >>
>> >> The commits are similar to my previous patch. I was doing atomics
>> >> similar
>> >> to uniform buffers, Now I was changing cso_context.
>> >>
>> >>>
>> >>> I believe that makes a lot more sense than creating a special counter
>> >>> buffer type only to be used for this. pipe_surface has the requisite
>> >>> offset/etc options.
>> >>
>> >>
>> >> I thought of using uniform buffer data structure with certain flags
>> >> which
>> >> differentiate between atomics, uniforms, index. Like a generic buffer.
>> >>
>> >>>
>> >>> I feel like I've mentioned this before when you asked questions, but
>> >>> I'd highly recommend taking my work and improving on it (or at least
>> >>> understanding it). It's at the point where a driver can implement the
>> >>> backend logic, although some of the mesa/st bits are going to be
>> >>> subject to discussion (and need fixing, it messes up the DCE tgsi
>> >>> pass, so I just disabled it).
>> >>>
>> >>> On Thu, Nov 13, 2014 at 12:18 AM, adityaatluri
>> >>> <adityaavinash1 at gmail.com>
>> >>> wrote:
>> >>> > ---
>> >>> > src/gallium/include/pipe/p_context.h | 5 +++++
>> >>> > src/gallium/include/pipe/p_defines.h | 7 ++++++-
>> >>> > src/gallium/include/pipe/p_state.h | 10 ++++++++++
>> >>> > 3 files changed, 21 insertions(+), 1 deletion(-)
>> >>> >
>> >>> > diff --git a/src/gallium/include/pipe/p_context.h
>> >>> > b/src/gallium/include/pipe/p_context.h
>> >>> > index af5674f..bf3be31 100644
>> >>> > --- a/src/gallium/include/pipe/p_context.h
>> >>> > +++ b/src/gallium/include/pipe/p_context.h
>> >>> > @@ -44,6 +44,7 @@ struct pipe_blit_info;
>> >>> > struct pipe_box;
>> >>> > struct pipe_clip_state;
>> >>> > struct pipe_constant_buffer;
>> >>> > +struct pipe_counter_buffer;
>> >>> > struct pipe_depth_stencil_alpha_state;
>> >>> > struct pipe_draw_info;
>> >>> > struct pipe_fence_handle;
>> >>> > @@ -201,6 +202,10 @@ struct pipe_context {
>> >>> > uint shader, uint index,
>> >>> > struct pipe_constant_buffer *buf );
>> >>> >
>> >>> > + void (*set_counter_buffer)( struct pipe_context *,
>> >>> > + uint shader, uint index,
>> >>> > + struct pipe_counter_buffer *buf );
>> >>> > +
>> >>> > void (*set_framebuffer_state)( struct pipe_context *,
>> >>> > const struct
>> >>> > pipe_framebuffer_state
>> >>> > * );
>> >>> >
>> >>> > diff --git a/src/gallium/include/pipe/p_defines.h
>> >>> > b/src/gallium/include/pipe/p_defines.h
>> >>> > index 8c4e415..717ab6a 100644
>> >>> > --- a/src/gallium/include/pipe/p_defines.h
>> >>> > +++ b/src/gallium/include/pipe/p_defines.h
>> >>> > @@ -341,6 +341,7 @@ enum pipe_flush_flags {
>> >>> > #define PIPE_BIND_VERTEX_BUFFER (1 << 4) /*
>> >>> > set_vertex_buffers
>> >>> > */
>> >>> > #define PIPE_BIND_INDEX_BUFFER (1 << 5) /* draw_elements */
>> >>> > #define PIPE_BIND_CONSTANT_BUFFER (1 << 6) /*
>> >>> > set_constant_buffer
>> >>> > */
>> >>> > +#define PIPE_BIND_COUNTER_BUFFER (1 << 7) /*
>> >>> > set_counter_buffer
>> >>> > */
>> >>> > #define PIPE_BIND_DISPLAY_TARGET (1 << 8) /*
>> >>> > flush_front_buffer
>> >>> > */
>> >>> > #define PIPE_BIND_TRANSFER_WRITE (1 << 9) /* transfer_map */
>> >>> > #define PIPE_BIND_TRANSFER_READ (1 << 10) /* transfer_map */
>> >>> > @@ -572,6 +573,8 @@ enum pipe_cap {
>> >>> > PIPE_CAP_MAX_VERTEX_ATTRIB_STRIDE = 109,
>> >>> > PIPE_CAP_SAMPLER_VIEW_TARGET = 110,
>> >>> > PIPE_CAP_CLIP_HALFZ = 111,
>> >>> > + PIPE_CAP_USER_COUNTER_BUFFERS = 112,
>> >>> > + PIPE_CAP_COUNTER_BUFFER_OFFSET_ALIGNMENT = 113,
>> >>> > };
>> >>> >
>> >>> > #define PIPE_QUIRK_TEXTURE_BORDER_COLOR_SWIZZLE_NV50 (1 << 0)
>> >>> > @@ -631,7 +634,9 @@ enum pipe_shader_cap
>> >>> > PIPE_SHADER_CAP_PREFERRED_IR,
>> >>> > PIPE_SHADER_CAP_TGSI_SQRT_SUPPORTED,
>> >>> > PIPE_SHADER_CAP_MAX_SAMPLER_VIEWS,
>> >>> > - PIPE_SHADER_CAP_DOUBLES
>> >>> > + PIPE_SHADER_CAP_DOUBLES,
>> >>> > + PIPE_SHADER_CAP_MAX_COUNTER_BUFFER_SIZE,
>> >>> > + PIPE_SHADER_CAP_MAX_COUNTER_BUFFERS
>> >>> > };
>> >>> >
>> >>> > /**
>> >>> > diff --git a/src/gallium/include/pipe/p_state.h
>> >>> > b/src/gallium/include/pipe/p_state.h
>> >>> > index 43bc48b..49fae5d 100644
>> >>> > --- a/src/gallium/include/pipe/p_state.h
>> >>> > +++ b/src/gallium/include/pipe/p_state.h
>> >>> > @@ -57,6 +57,7 @@ extern "C" {
>> >>> > #define PIPE_MAX_CLIP_PLANES 8
>> >>> > #define PIPE_MAX_COLOR_BUFS 8
>> >>> > #define PIPE_MAX_CONSTANT_BUFFERS 32
>> >>> > +#define PIPE_MAX_COUNTER_BUFFERS 32
>> >>> > #define PIPE_MAX_SAMPLERS 16
>> >>> > #define PIPE_MAX_SHADER_INPUTS 32
>> >>> > #define PIPE_MAX_SHADER_OUTPUTS 48 /* 32 GENERICs + POS, PSIZE,
>> >>> > FOG,
>> >>> > etc. */
>> >>> > @@ -462,6 +463,15 @@ struct pipe_constant_buffer {
>> >>> > const void *user_buffer; /**< pointer to a user buffer if
>> >>> > buffer
>> >>> > == NULL */
>> >>> > };
>> >>> >
>> >>> > +/**
>> >>> > + * A Counter buffer. A new buffer is set everytime a variable with
>> >>> > + * atomic_uint is defined.
>> >>> > + */
>> >>> > +struct pipe_counter_buffer{
>> >>> > + struct pipe_resource *buffer; /**< The actual buffer */
>> >>> > + unsigned buffer_offset; /**< The offset to start of data in
>> >>> > buffer
>> >>> > in bytes */
>> >>> > + const void *user_buffer; /**< The buffer which is created by the
>> >>> > compiler */
>> >>> > +};
>> >>> >
>> >>> > /**
>> >>> > * A stream output target. The structure specifies the range
>> >>> > vertices
>> >>> > can
>> >>> > --
>> >>> > 1.9.1
>> >>> >
>> >>> > _______________________________________________
>> >>> > mesa-dev mailing list
>> >>> > mesa-dev at lists.freedesktop.org
>> >>> > http://lists.freedesktop.org/mailman/listinfo/mesa-dev
>> >>
>> >>
>> >>
>> >> --
>> >> Regards,
>> >> Aditya Atluri,
>> >> USA.
>> >>
>> >>
>> >
>> >
>> >
>> > --
>> > Regards,
>> > Aditya Atluri,
>> > USA.
>> >
>
>
>
>
> --
> Regards,
> Aditya Atluri,
> USA.
>
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