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Re: Consensus: Tuning runtime behaviour with environment variables.


On Jun  2, 2013, Rich Felker <dalias@aerifal.cx> wrote:

> Do you have any performance figures to justify this?

Sure, in the paper.  It also explains the optimization you seem to have
missed, that enables the dynamic loader to turn dynamic TLS into
something very close to initial exec when the TLS segment of a dlopened
library fits in the static TLS segment.  I say you seem to have missed
that because you can't possibly be saying that all the work done by
__tls_get_addr() is as costly as simply returning the value passed in in
the correct register, that happens to be precomputed TLS offset.  The
shrink-wrapping of __tls_get_addr for the unfortunate cases in which the
TLS segment didn't fit is just a small added benefit.

-- 
Alexandre Oliva, freedom fighter    http://FSFLA.org/~lxoliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/   FSF Latin America board member
Free Software Evangelist      Red Hat Brazil Compiler Engineer


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