[Mesa-dev] [PATCH 4/4] glsl: Use hash table cloning in copy propagation

[Thomas Helland]

2017-01-13 18:41 GMT+01:00 Vladislav Egorov <vegorov180 at gmail.com>:
> 13.01.2017 15:31, Tapani Pälli пишет:
>>
>>
>>
>> On 01/12/2017 09:23 PM, Thomas Helland wrote:
>>>
>>> Walking the whole hash table, inserting entries by hashing them first
>>> is just a really really bad idea. We can simply memcpy the whole thing.
>>
>>
>> Maybe it is just 'really' not 'really really' since I don't spot any
>> difference in time running the torture test in bug #94477 (oscillates close
>> to 120s with both with and without these patches), I would expect at least
>> some difference as it is utilizing this path a lot. Did you measure
>> performance difference?
>>
>
> It wouldn't help the torture case from the bug, because that shader doesn't
> have LOOP and IF blocks, so more efficient copying the ACP for LOOP/IF
> blocks would not be even touched.
>
> Quick benchmark of Tom's patches on shader-db.
>
> Default shader-db, ./run -1, 10 runs:
>
>               BEFORE    AFTER
> softpipe      3.20s     3.15s
> radeonsi      5.17s     5.12s
> i965/Haswell  7.33s     7.19s
>
> On my full shader-db (50K+ shaders from games):
>
>                   BEFORE   AFTER
> softpipe (5 runs) 156.6s   153.9s
> i965              625s     613s
>
> So it brings 1-2% speed across the board.

What he said. It only helps when there are if's or loops.
The other patch I wrote based on Connor's suggestion makes a big impact.
But as he found out, and I confirmed, yesterday, the approach doesn't work.
So it is back to the drawing board on that one. And I thought I was so close :-/