[Mesa-dev] Time to merge threaded GL dispatch? (aka glthread)
Timothy Arceri
tarceri at itsqueeze.com
Fri Feb 10 22:31:40 UTC 2017
Just to clarify my email, I wasn't saying shader-cache should land
before this, or that we should prioritize one over the other. I was
simply venting frustration that I had to keep it rebased out of tree and
keep it passing piglit when it seems I didn't need too. This is nothing
against this series or Marek.
Shader-cache has been in a useful state for at least the past 6 months
it would have been nice to get it in and have real users testing. I
agree that this is probably the only way to get this series tested and
up to scratch also. I do think we should try to at least get piglit
mostly working before merging (looks like Gregory has made some progress
with this) even if piglit is unlikely to be the best test case for this,
it seems like it a low bar to have to clear.
Tim
On 11/02/17 00:29, Marek Olšák wrote:
> I never disagreed with you about shader cache and I never said that
> glthread would be merged first. I'm just describing the situation and
> recent news.
>
> Marek
>
>
> On Feb 10, 2017 2:15 PM, "Edward O'Callaghan"
> <funfunctor at folklore1984.net <mailto:funfunctor at folklore1984.net>> wrote:
>
> Wait what? You just side stepped everything I just said with
> regards to
> prioritizing the volume of work that went into shader caching over gl
> dispatch with essentially `gl dispatch is really great and our users
> friend it super useful now`.
>
> That's fine, I'm not ageist it, maybe you misinterpreted me? However
> that is nothing to do with what I was saying, as to reiterate my point
> was precise and finely scoped; We should get shader caching i's
> and t's
> dotted and crossed and help Timothy get though the last 5% there.
>
> Kind Regards,
> Edward.
>
> On 02/11/2017 12:01 AM, Marek Olšák wrote:
> > FYI. Civilization VI is another game that works with and
> benefits from
> > glthread. The game was just released. Even Nvidia is CPU-bound on
> > highest details and can't reach 45 fps with full hd. People
> wanting to
> > play Civ VI with decent frame rate will want glthread. I don't think
> > they care too much about our the community processes, so I
> expect there
> > will be quite a few users using out-of-tree builds of Mesa.
> >
> > Also, Pierre-Loup from Valve said on IRC yesterday that they are
> > probably gonna ship glthread and make their own whitelist,
> regardless of
> > the outcome of this discussion. It would be preferable to have that
> > whitelist in master too, but that may be difficult if we can't
> merge it.
> >
> > If distributions and vendors start shipping glthread, we might
> as well
> > merge it, because at that point there is no advantage in keeping
> this
> > out of tree if it forces users to use out of tree builds. We'll
> get bug
> > reports regardless.
> >
> > Also Eero, I don't care about glmark at this very moment. It's
> not like
> > I'm merging this today, so it doesn't matter. Maybe it will
> matter next
> > week or next month. We'll likely not support glmark anyway, so
> the fix
> > will most likely be disabling multithreading on the fly than
> trying to
> > fix the crash.
> >
> > Marek
> >
> >
> > On Feb 10, 2017 12:58 PM, "Edward O'Callaghan"
> > <funfunctor at folklore1984.net
> <mailto:funfunctor at folklore1984.net>
> <mailto:funfunctor at folklore1984.net
> <mailto:funfunctor at folklore1984.net>>> wrote:
> >
> >
> >
> > On 02/10/2017 10:50 PM, Marek Olšák wrote:
> > > On Fri, Feb 10, 2017 at 12:48 PM, Edward O'Callaghan
> > > <funfunctor at folklore1984.net
> <mailto:funfunctor at folklore1984.net>
> <mailto:funfunctor at folklore1984.net
> <mailto:funfunctor at folklore1984.net>>>
> > wrote:
> > >>
> > >>
> > >> On 02/10/2017 10:36 PM, Marek Olšák wrote:
> > >>> On Fri, Feb 10, 2017 at 12:26 PM, Edward O'Callaghan
> > >>> <funfunctor at folklore1984.net
> <mailto:funfunctor at folklore1984.net>
> > <mailto:funfunctor at folklore1984.net
> <mailto:funfunctor at folklore1984.net>>> wrote:
> > >>>>
> > >>>>
> > >>>> On 02/08/2017 09:13 AM, Timothy Arceri wrote:
> > >>>>> On Tue, 2017-02-07 at 10:56 +0100, Marek Olšák wrote:
> > >>>>>> On Tue, Feb 7, 2017 at 2:57 AM, Kenneth Graunke
> > <kenneth at whitecape.or
> > >>>>>> g> wrote:
> > >>>>>>> On Monday, February 6, 2017 8:54:40 PM PST Marek
> Olšák wrote:
> > >>>>>>>> On Mon, Feb 6, 2017 at 8:20 PM, Ernst Sjöstrand
> > <ernstp at gmail.com <mailto:ernstp at gmail.com>
> <mailto:ernstp at gmail.com <mailto:ernstp at gmail.com>>
> > >>>>>>>>> wrote:
> > >>>>>>>>> FYI glmark2 segfaults with mesa_glthread=true.
> Expected that
> > >>>>>>>>> some programs
> > >>>>>>>>> will segfault?
> > >>>>>>>>
> > >>>>>>>> Yes, even segfaults are expected with
> mesa_glthread=true.
> > >>>>>>>>
> > >>>>>>>> Marek
> > >>>>>>>
> > >>>>>>> Would it make sense to be crash-free or even
> regression-free
> > on at
> > >>>>>>> least Piglit, before merging? (Or are we there
> already?)
> > >>>>>>
> > >>>>>> It's not necessary. glthread is disabled by default.
> Nobody has
> > >>>>>> tested
> > >>>>>> piglit with glthread. That will follow after it's
> been merged, or
> > >>>>>> never if it's never merged.
> > >>>>>
> > >>>>> I've been trying to land shader-cache patches that
> actually do
> > pass
> > >>>>> piglit for over a year with the same reasoning that it
> will be
> > disable
> > >>>>> by default and can only be improved with testing I can't
> > possibly do on
> > >>>>> my own.
> > >>>>>
> > >>>>> Although I have no objections to this being merged I'll be
> > extremely
> > >>>>> frustrated if this is allowed to be merged known to
> not even pass
> > >>>>> piglit while I've wasted countless hours rebasing
> shader cache
> > over
> > >>>>> many months.
> > >>>>>
> > >>>>
> > >>>> Regardless of all the chatter on this thread in and
> around GL
> > dispatch,
> > >>>> which I agree poses significant challenges to get into
> > something 'ideal'
> > >>>> - which is hard to define for something like this..
> > >>>>
> > >>>> I think Timothy makes a really fair and just case here; in
> > that, could
> > >>>> we perhaps prioritize getting the shader cache stuff in
> before
> > >>>> attempting GL dispatch? I think this both morally and
> > technically the
> > >>>> right thing to do in my humble opinion.
> > >>>
> > >>> There is a small difference. The shader cache is
> expected to be
> > >>> enabled by default, so there is a certain level of
> quality required.
> > >>
> > >> Hey Marek,
> > >>
> > >> I am under the impression that it being enabled by
> default isn't
> > a hard
> > >> requirement for it to be merged. Maybe Timothy can weigh
> in on it
> > when
> > >> he is online?
> > >
> > > There is no official hard requirement. Everything is a
> judgement call
> > > based on circumstances.
> >
> > Yes, OK, I agree; So why assert the above response then? Who is
> > expecting it to be enabled by default? To reiterate I
> believe Timothy
> > would like it merged first and foremost, then perhaps enable
> it by
> > default if that is OK with everyone. I didn't see anywhere
> he expected
> > it to be on by default. However we should wait for his
> response on that.
> >
> > Regards,
> > Edward.
> >
> > >
> > > Marek
> > >
> >
>
>
>
>
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