Re: [Mesa-dev] [PATCH] i965: Don't use texture swizzling to force alpha to 1.0 if unnecessary.
Kenneth Graunke kenn...@whitecape.org writes: This partially fixes a performance regression since commit 33599433c7. More work is required to fully fix it in all cases. This at least helps Warsow. Thanks, Ken. Reviewed-by: Carl Worth cwo...@cworth.org -Carl pgpEBf6hWs_2H.pgp Description: PGP signature ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
Re: [Mesa-dev] [PATCH] i965: Don't use texture swizzling to force alpha to 1.0 if unnecessary.
On 03/15/2013 04:54 PM, Eric Anholt wrote: Kenneth Graunke kenn...@whitecape.org writes: Commit 33599433c7 began setting the texture swizzle mode to XYZ1 for RED, RG, and RGB textures in order to force alpha to 1.0 in case we actually stored the texture as RGBA. This had a unforseen performance implication: the shader precompile assumes that the texture swizzle mode will be XYZW for non-shadow sampler types. By setting it to XYZ1, this means every shader used with a RED, RG, or RGB texture has to be recompiled. This is a very common case. Unfortunately, there's no way to improve the precompile, since RGBA textures still need XYZW, and there's no way to know by looking at the shader source what texture formats might be used. However, we only need to smash alpha to 1.0 if the texture's memory format actually has alpha bits. If not, the sampler already returns 1.0 for us without any special swizzling. XRGB, for example, is a very common case where this occurs. This partially fixes a performance regression since commit 33599433c7. More work is required to fully fix it in all cases. This at least helps Warsow. Now that we have MESA_FORMAT_XBGR16161616_FLOAT and company, we could potentially make this conditional just die by using those formats. Absolutely - I believe the real fix is to use XRGB formats when sampling, and ARGB formats when rendering. I'm pretty sure we have formats for all of those now. We should do that. In the meantime, this patch improves things and is simple and easily cherry-pickable... --Ken ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
Re: [Mesa-dev] [PATCH] i965: Don't use texture swizzling to force alpha to 1.0 if unnecessary.
Kenneth Graunke kenn...@whitecape.org writes: On 03/15/2013 04:54 PM, Eric Anholt wrote: Kenneth Graunke kenn...@whitecape.org writes: Commit 33599433c7 began setting the texture swizzle mode to XYZ1 for RED, RG, and RGB textures in order to force alpha to 1.0 in case we actually stored the texture as RGBA. This had a unforseen performance implication: the shader precompile assumes that the texture swizzle mode will be XYZW for non-shadow sampler types. By setting it to XYZ1, this means every shader used with a RED, RG, or RGB texture has to be recompiled. This is a very common case. Unfortunately, there's no way to improve the precompile, since RGBA textures still need XYZW, and there's no way to know by looking at the shader source what texture formats might be used. However, we only need to smash alpha to 1.0 if the texture's memory format actually has alpha bits. If not, the sampler already returns 1.0 for us without any special swizzling. XRGB, for example, is a very common case where this occurs. This partially fixes a performance regression since commit 33599433c7. More work is required to fully fix it in all cases. This at least helps Warsow. Now that we have MESA_FORMAT_XBGR16161616_FLOAT and company, we could potentially make this conditional just die by using those formats. Absolutely - I believe the real fix is to use XRGB formats when sampling, and ARGB formats when rendering. I'm pretty sure we have formats for all of those now. We should do that. In the meantime, this patch improves things and is simple and easily cherry-pickable... Fair enough. Are there some big performance changes? pgpgynby9VcZq.pgp Description: PGP signature ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
Re: [Mesa-dev] [PATCH] i965: Don't use texture swizzling to force alpha to 1.0 if unnecessary.
On 03/16/2013 10:09 AM, Eric Anholt wrote: Kenneth Graunke kenn...@whitecape.org writes: On 03/15/2013 04:54 PM, Eric Anholt wrote: Kenneth Graunke kenn...@whitecape.org writes: Commit 33599433c7 began setting the texture swizzle mode to XYZ1 for RED, RG, and RGB textures in order to force alpha to 1.0 in case we actually stored the texture as RGBA. This had a unforseen performance implication: the shader precompile assumes that the texture swizzle mode will be XYZW for non-shadow sampler types. By setting it to XYZ1, this means every shader used with a RED, RG, or RGB texture has to be recompiled. This is a very common case. Unfortunately, there's no way to improve the precompile, since RGBA textures still need XYZW, and there's no way to know by looking at the shader source what texture formats might be used. However, we only need to smash alpha to 1.0 if the texture's memory format actually has alpha bits. If not, the sampler already returns 1.0 for us without any special swizzling. XRGB, for example, is a very common case where this occurs. This partially fixes a performance regression since commit 33599433c7. More work is required to fully fix it in all cases. This at least helps Warsow. Now that we have MESA_FORMAT_XBGR16161616_FLOAT and company, we could potentially make this conditional just die by using those formats. Absolutely - I believe the real fix is to use XRGB formats when sampling, and ARGB formats when rendering. I'm pretty sure we have formats for all of those now. We should do that. In the meantime, this patch improves things and is simple and easily cherry-pickable... Fair enough. Are there some big performance changes? No, not large in terms of FPS. Generally, when we get this wrong, we recompile each shader once and then it's right from then on. It does reduce stuttering quite a bit, though, since it means we don't have to recompile on first draw. I suppose it might affect very short demos. --Ken ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
[Mesa-dev] [PATCH] i965: Don't use texture swizzling to force alpha to 1.0 if unnecessary.
Commit 33599433c7 began setting the texture swizzle mode to XYZ1 for RED, RG, and RGB textures in order to force alpha to 1.0 in case we actually stored the texture as RGBA. This had a unforseen performance implication: the shader precompile assumes that the texture swizzle mode will be XYZW for non-shadow sampler types. By setting it to XYZ1, this means every shader used with a RED, RG, or RGB texture has to be recompiled. This is a very common case. Unfortunately, there's no way to improve the precompile, since RGBA textures still need XYZW, and there's no way to know by looking at the shader source what texture formats might be used. However, we only need to smash alpha to 1.0 if the texture's memory format actually has alpha bits. If not, the sampler already returns 1.0 for us without any special swizzling. XRGB, for example, is a very common case where this occurs. This partially fixes a performance regression since commit 33599433c7. More work is required to fully fix it in all cases. This at least helps Warsow. NOTE: This is a candidate for the 9.1 branch. Cc: Carl Worth cwo...@cworth.org Cc: Eric Anholt e...@anholt.net Signed-off-by: Kenneth Graunke kenn...@whitecape.org --- src/mesa/drivers/dri/i965/brw_wm_surface_state.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/src/mesa/drivers/dri/i965/brw_wm_surface_state.c b/src/mesa/drivers/dri/i965/brw_wm_surface_state.c index 0cb4b2d..771655d 100644 --- a/src/mesa/drivers/dri/i965/brw_wm_surface_state.c +++ b/src/mesa/drivers/dri/i965/brw_wm_surface_state.c @@ -773,7 +773,8 @@ brw_get_texture_swizzle(const struct gl_context *ctx, case GL_RED: case GL_RG: case GL_RGB: - swizzles[3] = SWIZZLE_ONE; + if (_mesa_get_format_bits(img-TexFormat, GL_ALPHA_BITS) 0) + swizzles[3] = SWIZZLE_ONE; break; } -- 1.8.2 ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
Re: [Mesa-dev] [PATCH] i965: Don't use texture swizzling to force alpha to 1.0 if unnecessary.
On 03/15/2013 03:14 PM, Kenneth Graunke wrote: Commit 33599433c7 began setting the texture swizzle mode to XYZ1 for RED, RG, and RGB textures in order to force alpha to 1.0 in case we actually stored the texture as RGBA. This had a unforseen performance implication: the shader precompile assumes that the texture swizzle mode will be XYZW for non-shadow sampler types. By setting it to XYZ1, this means every shader used with a RED, RG, or RGB texture has to be recompiled. This is a very common case. Unfortunately, there's no way to improve the precompile, since RGBA textures still need XYZW, and there's no way to know by looking at the shader source what texture formats might be used. I suspect that in a lot of cases the other components of the texture aren't used by the shader. Could we use that information somehow? We ought to be able to track which components of each sampler variable are used. However, we only need to smash alpha to 1.0 if the texture's memory format actually has alpha bits. If not, the sampler already returns 1.0 for us without any special swizzling. XRGB, for example, is a very common case where this occurs. This partially fixes a performance regression since commit 33599433c7. More work is required to fully fix it in all cases. This at least helps Warsow. NOTE: This is a candidate for the 9.1 branch. Cc: Carl Worth cwo...@cworth.org Cc: Eric Anholt e...@anholt.net Signed-off-by: Kenneth Graunke kenn...@whitecape.org --- src/mesa/drivers/dri/i965/brw_wm_surface_state.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/src/mesa/drivers/dri/i965/brw_wm_surface_state.c b/src/mesa/drivers/dri/i965/brw_wm_surface_state.c index 0cb4b2d..771655d 100644 --- a/src/mesa/drivers/dri/i965/brw_wm_surface_state.c +++ b/src/mesa/drivers/dri/i965/brw_wm_surface_state.c @@ -773,7 +773,8 @@ brw_get_texture_swizzle(const struct gl_context *ctx, case GL_RED: case GL_RG: case GL_RGB: - swizzles[3] = SWIZZLE_ONE; + if (_mesa_get_format_bits(img-TexFormat, GL_ALPHA_BITS) 0) + swizzles[3] = SWIZZLE_ONE; break; } ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
Re: [Mesa-dev] [PATCH] i965: Don't use texture swizzling to force alpha to 1.0 if unnecessary.
Kenneth Graunke kenn...@whitecape.org writes: Commit 33599433c7 began setting the texture swizzle mode to XYZ1 for RED, RG, and RGB textures in order to force alpha to 1.0 in case we actually stored the texture as RGBA. This had a unforseen performance implication: the shader precompile assumes that the texture swizzle mode will be XYZW for non-shadow sampler types. By setting it to XYZ1, this means every shader used with a RED, RG, or RGB texture has to be recompiled. This is a very common case. Unfortunately, there's no way to improve the precompile, since RGBA textures still need XYZW, and there's no way to know by looking at the shader source what texture formats might be used. However, we only need to smash alpha to 1.0 if the texture's memory format actually has alpha bits. If not, the sampler already returns 1.0 for us without any special swizzling. XRGB, for example, is a very common case where this occurs. This partially fixes a performance regression since commit 33599433c7. More work is required to fully fix it in all cases. This at least helps Warsow. Now that we have MESA_FORMAT_XBGR16161616_FLOAT and company, we could potentially make this conditional just die by using those formats. pgpzWJJvQCiwz.pgp Description: PGP signature ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
