[Mesa-dev] [PATCH v3 000/104] nir: Move to using instructions for derefs
Caio Marcelo de Oliveira Filho
caio.oliveira at intel.com
Mon Apr 9 23:58:04 UTC 2018
Hi,
Given the fixes you already made based on my comments. Patches 1-20,
22-27, 29-43, and 61 (multiview!) are
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira at intel.com>
Patches 46-47 and 49 seem to be valid regardless the rest of the code,
so I'd consider getting them in independently. They are also R-b'ed.
I've skipped 21 and 28 because I wanted to give a deeper look at the
originals.
>From the perspective of someone that is living with deref_vars for
just a short time, I like the idea of removing one special
construction (derefs) and rely on instructions instead.
Which made me wonder: was there a special factor that led NIR to start
with the "old-school derefs" in the first place? Other day Curro asked
about one of the "selling points" of NIR being it did not have all
those nodes representing dereferences. I digged up an old comment to
what I think he was referring to
https://lists.freedesktop.org/archives/mesa-dev/2014-February/053477.html
- All the ir_dereference chains blow up the memory usage, and the
constant pointer chasing in the recursive algorithms needed to handle
them is not just cache-unfriendly but "cache-mean."
How does deref_instructions avoid being "cache-mean" as their
"predecessors"? Was the blow up more a result of how the instructions
were structured than the fact it had those dereferences nodes?
Thanks,
Caio
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