On 2016-02-24 12:47, Marek Olšák wrote:
On Wed, Feb 24, 2016 at 12:22 PM, Grigori Goronzy <g...@chown.ath.cx>
wrote:
S_00B32C_SCRATCH_EN(shader->config.scratch_bytes_per_wave > 0));
+
+ /* Prefer RE_Z if the shader is complex enough. */
+ if (info->num_memory_instructions >= 2 ||
+ shader->binary.code_size > 100*4)
+ shader->z_order = V_02880C_EARLY_Z_THEN_RE_Z;
+ else
+ shader->z_order = V_02880C_EARLY_Z_THEN_LATE_Z;
}
Are these thresholds for switching to re-Z based on measurements,
feedback
by the HW team or are they just a shot in the dark?
Either way, the magic numbers don't look particularly nice. Maybe
preprocessor constants should be introduced for them?
They are not so magic. The meaning is 2 memory instructions or
instruction count between 50 and 100. They are based on my estimates
and expectations.
Of course the semantics are easy to understand, but what the reasoning
behind the constant's values is, that is not clear.
I think it's always useful to assign names to such tunables and to put
them into a central place (e.g. at the top of a file, together with
other #defines).
It's just a suggestion, though, I don't want to bikeshed this any
further. :)
Grigori
No benchmarking has been done, but there is a potential to gain some
performance with shaders killing pixels.
Marek
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