On 27.06.2017 17:02, Marek Olšák wrote:
On Tue, Jun 27, 2017 at 10:02 AM, Nicolai Hähnle <nhaeh...@gmail.com> wrote:
On 27.06.2017 00:15, Marek Olšák wrote:
On Thu, Jun 22, 2017 at 9:19 AM, Nicolai Hähnle <nhaeh...@gmail.com>
wrote:
On 20.06.2017 20:00, Marek Olšák wrote:
From: Marek Olšák <marek.ol...@amd.com>
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.
It decreases the time spent in si_update_shaders by 6% when going from
128 bytes to 106 for the shader key.
What do you mean by the risk?
If we end up accidentally misaligning a member, that could cause a
performance hit. But those 6% improvement does seem worth it. I do think
Emil's suggestion of adding the attribute directly to the structures is a
good idea. With that, the patch is
I can't add the attributes inside the structures, because every
structure member would have to have the attribute, and that would be
too much noise in the code. There are MSVC and gcc attributes. gcc
supports both kinds. MSVC attributes are the global #pragmas. gcc
attributes are per-member or on structure types. If the attribute is
on a structure type, it only specifies alignment for the whole
structure, not individual members.
My bad, I thought there was an attribute that controls the packing of
all members. If there isn't, just go ahead with the patch as-is.
Cheers,
Nicolai
Marek
--
Lerne, wie die Welt wirklich ist,
Aber vergiss niemals, wie sie sein sollte.
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