[Mesa-users] Trouble compiling MesaGL : llvm intrinsics seem to be missing.

[Chuck Atkins]

>
> The other thing is: does swr work with osmesa? I can't test right now.
>

Yep.  It works with GLX, OSMesa, of which I use it in both extensively, and
if I'm not mistaken, also EGL (although I haven't used it yet with EGL).



> > Okay seems you are right, either configuration options have at some
> > point changed or I somehow with my mesa configs magically got by. In
> > the case of the latter it must seem pretty funny/sad that I am
> > imagining configure flags.
>

Not at all.  I've often felt that getting right set of config options in
mesa can be a bit of "black magic".  The confusion / error is entirely
understandable.  I just happen to know it well because I spent quite a bit
of time "fixing" an issue with the enable-glx options, which in turn made
me far mor familiar with the mesa auto-conf implementation than I expected.



> > Thanks for the information on llvmpipe vs swr it is interesting
> > (assuming those numbers are on a single PC).
>

Yep.  Single machine.  Performance numbers are always relative to actual
workload so two different benchmarks may show a significant different in
performance but the relative difference between llvmpipe -> swr and old-swr
-> new-swr seems pretty consistent.



> Sorry I mispredicted the quality of swr.
>

No worries. Sorry if I came across more defensive / agressive as that
certainly was not my intent.  I'm not actually one of the swr developers
but I do work closely with the Intel developers who are since our software
is one of thier primary use cases.  I think swr in particular is often
misunderstoond by many and in all fairness, the early implementations had
thier issues (what software doesn't though right?).  The current state of
affairs though in 13.0 has really raised the bar.

Even though swr is fast and highly parallelized for many workloads,
llvmpipe still makes sense in a lot of use cases.  You'll generaly end up
with both in the same Mesa build anyways so it's pretty easy to run your
own tests, switching back and forth between llvmpipe and swr, to determine
what works best for your particular application and rendering workloads.


Chuck Atkins
Staff R&D Engineer - Scientific Computing
Kitware, Inc.
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