[Mesa-dev] [PATCH] docs: describe the NVC0_COMPUTE envvar

[Ilia Mirkin]

On Sun, Mar 1, 2015 at 4:55 PM, Samuel Pitoiset
<samuel.pitoiset at gmail.com> wrote:
>
> On 03/01/2015 07:21 PM, Ilia Mirkin wrote:
>>
>> Why wouldn't they always just be enabled :) Also, do you have to set
>> it to get MP counters on kepler+? And why is it called "compute" if it
>> enables performance counters... probably does more than that, no?
>
>
> It is not enabled by default because compute support on Fermi has weird
> effects on 3D. And, I didn't find the time to investigate about this, that's
> why it is still a bit experimental. :)
>
> Actually, NVC0_COMPUTE allows compute support which is required for MP
> counters in order to polls them. However, we only have to set it for
> nvc0:nve4 chipsets, so the documentation of this envvar could be more
> accurate.
>
> Should I have to submit a v2 and improve the documentation by something like
> "NVC0_COMPUTE - enable compute support which is required for MP performance
> counters on nvc0:nve4" ?

It's unclear to me that this option should be advertised at all. First
off it has weird side-effects, and secondly none of the other nouveau
env vars are listed there (NV50_PROG_DEBUG/NV50_PROG_OPTIMIZE).

However if you feel strongly about it, how about

"Enable compute support on Fermi chips. This is required for ______ .
However it has side-effects of ______ ."

Note that "MP performance counters" only makes sense to people who are
already fully aware of the NVC0_COMPUTE env var, and if they weren't,
the first place they'd look would be in the code and not that envvars
page.

  -ilia