On 20.06.2017 20:00, Marek Olšák wrote:
From: Marek Olšák <[email protected]>
sizeof(struct si_shader_key):
Before reverting the 2 commits: 120 bytes
After reverting the 2 commits: 128 bytes
With #pragma pack: 107 bytes
I'm not sure if memcmp with a byte-aligned size is a good idea.
Does this have a measurable impact? The code is nicer to read with the
structure after the patches, but I'm not sure it's worth the risk of
getting misaligned data somewhere.
Nicolai
---
src/gallium/drivers/radeonsi/si_shader.h | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/src/gallium/drivers/radeonsi/si_shader.h
b/src/gallium/drivers/radeonsi/si_shader.h
index 185bb8d..6432126 100644
--- a/src/gallium/drivers/radeonsi/si_shader.h
+++ b/src/gallium/drivers/radeonsi/si_shader.h
@@ -371,20 +371,25 @@ struct si_shader_selector {
* GFX6 - with GS: ES | | | GS | VS | PS
* - with tess: LS | HS | VS | | | PS
* - with both: LS | HS | ES | GS | VS | PS
* GFX9 - with GS: -> | | | GS | VS | PS
* - with tess: -> | HS | VS | | | PS
* - with both: -> | HS | -> | GS | VS | PS
*
* -> = merged with the next stage
*/
+/* Use the byte alignment for all following structure members for optimal
+ * shader key memory footprint.
+ */
+#pragma pack(push, 1)
+
/* Common VS bits between the shader key and the prolog key. */
struct si_vs_prolog_bits {
unsigned instance_divisors[SI_MAX_ATTRIBS];
};
/* Common TCS bits between the shader key and the epilog key. */
struct si_tcs_epilog_bits {
unsigned prim_mode:3;
unsigned tes_reads_tess_factors:1;
};
@@ -507,20 +512,23 @@ struct si_shader_key {
/* For shaders where monolithic variants have better code.
*
* This is a flag that has no effect on code generation,
* but forces monolithic shaders to be used as soon as
* possible, because it's in the "opt" group.
*/
unsigned prefer_mono:1;
} opt;
};
+/* Restore the pack alignment to default. */
+#pragma pack(pop)
+
struct si_shader_config {
unsigned num_sgprs;
unsigned num_vgprs;
unsigned spilled_sgprs;
unsigned spilled_vgprs;
unsigned private_mem_vgprs;
unsigned lds_size;
unsigned spi_ps_input_ena;
unsigned spi_ps_input_addr;
unsigned float_mode;
--
Lerne, wie die Welt wirklich ist,
Aber vergiss niemals, wie sie sein sollte.
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