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Re: glibc -- ISO C11 threads Proposal
- From: Rich Felker <dalias at aerifal dot cx>
- To: Kevin Cox <kevincox at kevincox dot ca>
- Cc: Torvald Riegel <triegel at redhat dot com>, Carlos O'Donell <carlos at redhat dot com>, libc-alpha at sourceware dot org
- Date: Wed, 26 Mar 2014 21:56:42 -0400
- Subject: Re: glibc -- ISO C11 threads Proposal
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- References: <53260E7E dot 8070308 at kevincox dot ca> <1395771092 dot 19076 dot 1236 dot camel at triegel dot csb> <5331C7EA dot 6050407 at redhat dot com> <1395777699 dot 19076 dot 1469 dot camel at triegel dot csb> <20140325212732 dot GC26358 at brightrain dot aerifal dot cx> <53337E8B dot 50508 at kevincox dot ca>
On Wed, Mar 26, 2014 at 09:27:39PM -0400, Kevin Cox wrote:
> On 25/03/14 17:27, Rich Felker wrote:
> > On Tue, Mar 25, 2014 at 09:01:39PM +0100, Torvald Riegel wrote:
> >> On Tue, 2014-03-25 at 14:16 -0400, Carlos O'Donell wrote:
> >>
> >> We could also try to make some of the C11 types smaller (or at least not
> >> make them bigger) to reduce space overhead. (For example, for
> >> fine-granular locking.)
> >
> > I'm generally against making them bigger; the C11 synchronization
> > objects are MUCH weaker than the POSIX ones in terms of their
> > specifications/interface contracts, and there's no use for the space
> > we already have. Making them larger just makes it more expensive to
> > have synchronization objects as part of other objects, which forces
> > developers to choose between bloat and coarse-grained locking.
> >
> > So IMO the question to ask is whether to keep the sizes the same, or
> > make them smaller. Making them smaller would require new mtx/cond
> > implementations for C11 but might have some other benefits too,
> > including performance.
> >
>
> I think for this project it is best to leave them as the pthread ones.
> Since I will be removing the translation functions we will be free to
> "upgrade" them in the future if desired.
So in that case, the object sizes (for ABI purposes) will match the
pthread ones. Is that ok with everyone?
Rich