[Mesa-dev] [PATCH 3/4] radeonsi: add more unlikely() uses into si_draw_vbo

[Nicolai Hähnle]

On 07.09.2016 12:23, Marek Olšák wrote:
> On Wed, Sep 7, 2016 at 11:47 AM, Michel Dänzer <michel at daenzer.net> wrote:
>> On 07/09/16 06:02 PM, Marek Olšák wrote:
>>>
>>> Based on the comments so far, it looks like all annotations in the
>>> patch are very well placed, so I don't know what the fuss is about.
>>
>> As I said, there's no question about the first three annotations, but
>> for the last two we can't know whether they help or actually hurt
>> without measuring it. That's the whole point.
>
> OK. The last two are so rare that their likeliness is below 1%. The
> conditions are true when discarding CMASK or DCC, changing the micro
> tile mode of a texture, reallocating texture storage, and degrading
> the tile mode to linear. Some of those are caused by SDMA doing a
> whole-layer overwrite, a texture transfer, or a buffer handle export.
> Some of them can occur only once during the lifetime of a texture.
> They are very rare during normal gaming, which just consists of state
> changes and draw calls and nothing in between. I don't know about
> microbenchmarks.

FWIW, though I haven't said so explicitly (other than sending my R-b 
while this discussion was already going on), I also think those last two 
cases are fine. We probably shouldn't go overboard with the (un)likely, 
but really, the patch is fine as is.

Nicolai

>
> Marek
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