[Mesa-dev] [PATCH] gallium: add PIPE_RESOURCE_FLAG_TEXTURING_MORE_LIKELY

[Marek Olšák]

On Thu, Oct 13, 2016 at 2:09 AM, Roland Scheidegger <sroland at vmware.com> wrote:
> Am 12.10.2016 um 15:29 schrieb Marek Olšák:
>> From: Marek Olšák <marek.olsak at amd.com>
>>
>> For performance tuning in drivers. It filters out window system
>> framebuffers and OpenGL renderbuffers.
>>
>> radeonsi will use this to guess whether a depth buffer will be read
>> by a shader. There is no guarantee about what will actually happen.
>>
>> This is a departure from PIPE_BIND flags which are defined to be strict
>> but they are useless in practice.
>> ---
>>  src/gallium/include/pipe/p_defines.h | 1 +
>>  src/mesa/state_tracker/st_texture.c  | 3 ++-
>>  2 files changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/src/gallium/include/pipe/p_defines.h b/src/gallium/include/pipe/p_defines.h
>> index db96c51..037ed92 100644
>> --- a/src/gallium/include/pipe/p_defines.h
>> +++ b/src/gallium/include/pipe/p_defines.h
>> @@ -443,20 +443,21 @@ enum pipe_flush_flags
>>  #define PIPE_BIND_SCANOUT     (1 << 19) /*  */
>>  #define PIPE_BIND_SHARED      (1 << 20) /* get_texture_handle ??? */
>>  #define PIPE_BIND_LINEAR      (1 << 21)
>>
>>
>>  /**
>>   * Flags for the driver about resource behaviour:
>>   */
>>  #define PIPE_RESOURCE_FLAG_MAP_PERSISTENT (1 << 0)
>>  #define PIPE_RESOURCE_FLAG_MAP_COHERENT   (1 << 1)
>> +#define PIPE_RESOURCE_FLAG_TEXTURING_MORE_LIKELY (1 << 2)
>>  #define PIPE_RESOURCE_FLAG_DRV_PRIV    (1 << 16) /* driver/winsys private */
>>  #define PIPE_RESOURCE_FLAG_ST_PRIV     (1 << 24) /* state-tracker/winsys private */
>>
>>  /**
>>   * Hint about the expected lifecycle of a resource.
>>   * Sorted according to GPU vs CPU access.
>>   */
>>  enum pipe_resource_usage {
>>     PIPE_USAGE_DEFAULT,        /* fast GPU access */
>>     PIPE_USAGE_IMMUTABLE,      /* fast GPU access, immutable */
>> diff --git a/src/mesa/state_tracker/st_texture.c b/src/mesa/state_tracker/st_texture.c
>> index a2c36ac..7b72ffd 100644
>> --- a/src/mesa/state_tracker/st_texture.c
>> +++ b/src/mesa/state_tracker/st_texture.c
>> @@ -84,21 +84,22 @@ st_texture_create(struct st_context *st,
>>     memset(&pt, 0, sizeof(pt));
>>     pt.target = target;
>>     pt.format = format;
>>     pt.last_level = last_level;
>>     pt.width0 = width0;
>>     pt.height0 = height0;
>>     pt.depth0 = depth0;
>>     pt.array_size = layers;
>>     pt.usage = PIPE_USAGE_DEFAULT;
>>     pt.bind = bind;
>> -   pt.flags = 0;
>> +   /* only set this for OpenGL textures, not renderbuffers */
>> +   pt.flags = PIPE_RESOURCE_FLAG_TEXTURING_MORE_LIKELY;
>>     pt.nr_samples = nr_samples;
>>
>>     newtex = screen->resource_create(screen, &pt);
>>
>>     assert(!newtex || pipe_is_referenced(&newtex->reference));
>>
>>     return newtex;
>>  }
>>
>>
>>
>
> I guess, why not... I bet though there are apps which create everything
> as a texture, regardless if they actually use it for sampling or not. So
> you still need to try to not perform too bad if you got the hint wrong :-).
> It's really GL which is useless there, not the PIPE_BIND flags ;-).

But you have to admit that the new flag is very accurate - it
represents OpenGL texture objects. That can't be said about most of
the bind flags.

Marek