From owner-freebsd-threads@FreeBSD.ORG  Mon Jun 16 15:20:08 2003
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Date: Mon, 16 Jun 2003 18:20:00 -0400 (EDT)
From: Daniel Eischen <eischen@pcnet.com>
To: Julian Elischer <julian@elischer.org>
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cc: zander@mail.minion.de
cc: Gareth Hughes <gareth@nvidia.com>
cc: Andy Ritger <ARitger@nvidia.com>
Subject: RE: NVIDIA and TLS
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On Mon, 16 Jun 2003, Julian Elischer wrote:
> 
> On Mon, 16 Jun 2003, Gareth Hughes wrote:
> 
> > On Mon, 16 Jun 2003, Andy Ritger wrote:
> > > 
> > > So from an OpenGL point of view, here are several alternatives that
> > > I see for atleast the near term:
> > > 
> > >     - make NVIDIA's OpenGL implementation not thread-safe (just
> > >       use global data rather that thread-local data)
> > > 
> > >     - accept the performance hit of using pthread_getspecific()
> > >       on FreeBSD.  From talking to other OpenGL engineers,
> > >       conservative estimates of the performance impact on
> > >       applications like viewperf range from 10% - 15%.  I'd like
> > >       to quantify that, but certainly there will be a performance
> > >       penalty.
> > 
> > And these are *very* conservative estimates -- you're essentially adding a
> > function call into a path that is, on average, less than ten instructions
> > per OpenGL API call, where the number of API calls per frame is upward of 3

I see this as a problem with the OpenGL API.  You're trying
to make something thread-safe that isn't by its nature.
I would rather see OpenGL-MT with new interfaces that
are by nature thread-safe.

-- 
Dan Eischen