[Mesa-dev] [PATCH] radeonsi: enable denorms for 64-bit and 16-bit floats
Tom Stellard
tom at stellard.net
Mon Feb 8 16:08:31 UTC 2016
On Sat, Feb 06, 2016 at 01:15:42PM +0100, Marek Olšák wrote:
> From: Marek Olšák <marek.olsak at amd.com>
>
> This fixes FP16 conversion instructions for VI, which has 16-bit floats,
> but not SI & CI, which can't disable denorms for those instructions.
Do you know why this fixes FP16 conversions? What does the OpenGL
spec say about denormal handing?
> ---
> src/gallium/drivers/radeonsi/si_shader.c | 14 ++++++++++++++
> src/gallium/drivers/radeonsi/si_state_shaders.c | 18 ++++++++++++------
> src/gallium/drivers/radeonsi/sid.h | 3 +++
> 3 files changed, 29 insertions(+), 6 deletions(-)
>
> diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
> index a4680ce..3f1db70 100644
> --- a/src/gallium/drivers/radeonsi/si_shader.c
> +++ b/src/gallium/drivers/radeonsi/si_shader.c
> @@ -4155,6 +4155,20 @@ int si_compile_llvm(struct si_screen *sscreen,
>
> si_shader_binary_read_config(binary, conf, 0);
>
> + /* Enable 64-bit and 16-bit denormals, because there is no performance
> + * cost.
> + *
> + * If denormals are enabled, all floating-point output modifiers are
> + * ignored.
> + *
> + * Don't enable denormals for 32-bit floats, because:
> + * - Floating-point output modifiers would be ignored by the hw.
> + * - Some opcodes don't support denormals, such as v_mad_f32. We would
> + * have to stop using those.
> + * - SI & CI would be very slow.
> + */
> + conf->float_mode |= V_00B028_FP_64_DENORMS;
> +
Do SI/CI support fp64 denorms? If so, won't this hurt performance?
We should tell the compiler we are enabling fp-64 denorms by adding
+fp64-denormals to the feature string. It would also be better to
read the float_mode value from the config registers emitted by the
compiler.
-Tom
> FREE(binary->config);
> FREE(binary->global_symbol_offsets);
> binary->config = NULL;
> diff --git a/src/gallium/drivers/radeonsi/si_state_shaders.c b/src/gallium/drivers/radeonsi/si_state_shaders.c
> index ce795c0..77a4e47 100644
> --- a/src/gallium/drivers/radeonsi/si_state_shaders.c
> +++ b/src/gallium/drivers/radeonsi/si_state_shaders.c
> @@ -124,7 +124,8 @@ static void si_shader_ls(struct si_shader *shader)
> shader->config.rsrc1 = S_00B528_VGPRS((shader->config.num_vgprs - 1) / 4) |
> S_00B528_SGPRS((num_sgprs - 1) / 8) |
> S_00B528_VGPR_COMP_CNT(vgpr_comp_cnt) |
> - S_00B528_DX10_CLAMP(1);
> + S_00B528_DX10_CLAMP(1) |
> + S_00B528_FLOAT_MODE(shader->config.float_mode);
> shader->config.rsrc2 = S_00B52C_USER_SGPR(num_user_sgprs) |
> S_00B52C_SCRATCH_EN(shader->config.scratch_bytes_per_wave > 0);
> }
> @@ -157,7 +158,8 @@ static void si_shader_hs(struct si_shader *shader)
> si_pm4_set_reg(pm4, R_00B428_SPI_SHADER_PGM_RSRC1_HS,
> S_00B428_VGPRS((shader->config.num_vgprs - 1) / 4) |
> S_00B428_SGPRS((num_sgprs - 1) / 8) |
> - S_00B428_DX10_CLAMP(1));
> + S_00B428_DX10_CLAMP(1) |
> + S_00B428_FLOAT_MODE(shader->config.float_mode));
> si_pm4_set_reg(pm4, R_00B42C_SPI_SHADER_PGM_RSRC2_HS,
> S_00B42C_USER_SGPR(num_user_sgprs) |
> S_00B42C_SCRATCH_EN(shader->config.scratch_bytes_per_wave > 0));
> @@ -203,7 +205,8 @@ static void si_shader_es(struct si_shader *shader)
> S_00B328_VGPRS((shader->config.num_vgprs - 1) / 4) |
> S_00B328_SGPRS((num_sgprs - 1) / 8) |
> S_00B328_VGPR_COMP_CNT(vgpr_comp_cnt) |
> - S_00B328_DX10_CLAMP(1));
> + S_00B328_DX10_CLAMP(1) |
> + S_00B328_FLOAT_MODE(shader->config.float_mode));
> si_pm4_set_reg(pm4, R_00B32C_SPI_SHADER_PGM_RSRC2_ES,
> S_00B32C_USER_SGPR(num_user_sgprs) |
> S_00B32C_SCRATCH_EN(shader->config.scratch_bytes_per_wave > 0));
> @@ -292,7 +295,8 @@ static void si_shader_gs(struct si_shader *shader)
> si_pm4_set_reg(pm4, R_00B228_SPI_SHADER_PGM_RSRC1_GS,
> S_00B228_VGPRS((shader->config.num_vgprs - 1) / 4) |
> S_00B228_SGPRS((num_sgprs - 1) / 8) |
> - S_00B228_DX10_CLAMP(1));
> + S_00B228_DX10_CLAMP(1) |
> + S_00B228_FLOAT_MODE(shader->config.float_mode));
> si_pm4_set_reg(pm4, R_00B22C_SPI_SHADER_PGM_RSRC2_GS,
> S_00B22C_USER_SGPR(num_user_sgprs) |
> S_00B22C_SCRATCH_EN(shader->config.scratch_bytes_per_wave > 0));
> @@ -381,7 +385,8 @@ static void si_shader_vs(struct si_shader *shader, struct si_shader *gs)
> S_00B128_VGPRS((shader->config.num_vgprs - 1) / 4) |
> S_00B128_SGPRS((num_sgprs - 1) / 8) |
> S_00B128_VGPR_COMP_CNT(vgpr_comp_cnt) |
> - S_00B128_DX10_CLAMP(1));
> + S_00B128_DX10_CLAMP(1) |
> + S_00B128_FLOAT_MODE(shader->config.float_mode));
> si_pm4_set_reg(pm4, R_00B12C_SPI_SHADER_PGM_RSRC2_VS,
> S_00B12C_USER_SGPR(num_user_sgprs) |
> S_00B12C_SO_BASE0_EN(!!shader->selector->so.stride[0]) |
> @@ -567,7 +572,8 @@ static void si_shader_ps(struct si_shader *shader)
> si_pm4_set_reg(pm4, R_00B028_SPI_SHADER_PGM_RSRC1_PS,
> S_00B028_VGPRS((shader->config.num_vgprs - 1) / 4) |
> S_00B028_SGPRS((num_sgprs - 1) / 8) |
> - S_00B028_DX10_CLAMP(1));
> + S_00B028_DX10_CLAMP(1) |
> + S_00B028_FLOAT_MODE(shader->config.float_mode));
> si_pm4_set_reg(pm4, R_00B02C_SPI_SHADER_PGM_RSRC2_PS,
> S_00B02C_EXTRA_LDS_SIZE(shader->config.lds_size) |
> S_00B02C_USER_SGPR(num_user_sgprs) |
> diff --git a/src/gallium/drivers/radeonsi/sid.h b/src/gallium/drivers/radeonsi/sid.h
> index 9e1e158..8920847 100644
> --- a/src/gallium/drivers/radeonsi/sid.h
> +++ b/src/gallium/drivers/radeonsi/sid.h
> @@ -2845,6 +2845,9 @@
> #define S_00B028_FLOAT_MODE(x) (((x) & 0xFF) << 12)
> #define G_00B028_FLOAT_MODE(x) (((x) >> 12) & 0xFF)
> #define C_00B028_FLOAT_MODE 0xFFF00FFF
> +#define V_00B028_FP_32_DENORMS 0x30
> +#define V_00B028_FP_64_DENORMS 0xc0
> +#define V_00B028_FP_ALL_DENORMS 0xf0
> #define S_00B028_PRIV(x) (((x) & 0x1) << 20)
> #define G_00B028_PRIV(x) (((x) >> 20) & 0x1)
> #define C_00B028_PRIV 0xFFEFFFFF
> --
> 2.1.4
>
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