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Re: externs and thread local storage

From: Richard Henderson <rth at redhat dot com>
To: Robert Dewar <dewar at adacore dot com>
Cc: Gary Funck <gary at intrepid dot com>, "'Gcc Mailing List'" <gcc at gcc dot gnu dot org>
Date: Mon, 10 Jul 2006 09:21:54 -0700
Subject: Re: externs and thread local storage
References: <65FB4106-0EEE-49BB-AE0E-8FACEE85C9C4@physics.uc.edu> <JCEPIPKHCJGDMPOHDOIGOEIIDFAA.gary@intrepid.com> <20060707232215.GA5277@redhat.com> <44AF1EC8.6000104@adacore.com>

On Fri, Jul 07, 2006 at 10:56:08PM -0400, Robert Dewar wrote:
> That's not true, thread local storage can be done simply by mapping
> hardware on some machines, where you swap maps on a context switch.

Not with the semantics we have for __thread, which asserts
that its address is valid in all threads.

And, no one has tried this since Irix, wherein it didn't 
perform well.  the effects of tlb flushing at context
switch are heavy.

r~

References:
- Re: externs and thread local storage
  - From: Andrew Pinski
- RE: externs and thread local storage
  - From: Gary Funck
- Re: externs and thread local storage
  - From: Richard Henderson
- Re: externs and thread local storage
  - From: Robert Dewar

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