[Mesa-dev] V2 radeonsi use STD430 packing of UBOs by default

[Timothy Arceri]

On 31/08/17 01:55, Marek Olšák wrote:
> On Wed, Aug 30, 2017 at 2:22 PM, Timothy Arceri <tarceri at itsqueeze.com> wrote:
>> On 30/08/17 20:07, Marek Olšák wrote:
>>>
>>> If LLVM was fixed to do the correct thing, we could enable CONSTBUF
>>> LOAD for LLVM 6.0 and later.
>>
>>
>> You seem to think that the compiler *should* be placing them near where they
>> are used? What part of LLVM were you expecting to do this? I'm happy to do
>> some digging around but don't know where I should start looking.
> 
> I think the LLVM machine instruction scheduler should do that. The
> starting point would be to add "-print-after-all" to llc or LLVM
> arguments in Mesa to have visibility into what LLVM is doing. From
> that point it's just about learning to understand that. By default,
> LLVM assumes that most or all loads may be affected by any store. LLVM
> might also think that the instruction order is OK and doesn't need
> changes. I don't know what the exact issue is.
> 
> If Natural Selection 2 is the only game showing small changes in
> shader-db stats and there are no differences in *real performance* of
> NS2 and other apps, I'd say let's merge this.

Retesting with master and more recent LLVM I'm getting:

MaxWaves -1.68% (previously was -2.94%) with -1.60% for NS2.

My care factor for NS2 has officially dropped to 0. I got a copy of it 
for testing but I noticed:

  1. OpenGL support is still marked as beta
  2. It crashes when I try to load the tutorial, I assume its related to
     this bug [1].

Since this is the case I'd rather not hold up this work based on the 
results of a buggy game. Marek is patch 4 ok with you? Everything else 
has you r-b (once I split patch 7).

Thanks,
Tim

[1] https://bugs.freedesktop.org/show_bug.cgi?id=93301

> 
> Marek
>