[Pkg-db-devel] Bug#520926: Bug#520926: should be built with --enable-posixmutexes --with-mutex=POSIX/pthreads

[John Morrissey]

On Fri, Apr 10, 2009 at 12:57:40PM +0200, Florian Weimer wrote:
> * John Morrissey:
> > tl;dr summary: It seems BerkeleyDB should be built with:
> >
> > 	--enable-posixmutexes --with-mutex=POSIX/pthreads
> >
> > on NPTL Linux systems, since native POSIX mutexes substantially
> > lower context switches, at least with OpenLDAP's slapd.
> 
> Wasn't it the other way round for previous versions?  Anyway, I think
> this is the way to go, but we can't do it on all architectures because
> some of them are still not NPTL-enabled.  We also should get it right
> early because changing the mutex algorithm changes the database
> environment layout in a way which cannot detected by Berkeley DB.
> 
> If you think it's not too late for that, we can make the change now,
> or with the release of version 4.8.

Hm, I'm really not sure I'm the one to answer that question (if it's indeed
me you're asking it of). I've already backported and forked libdb4.7
locally, so I filed this bug mostly as an FYI that this is a change you
might want to make to the Debian packaging, since it seems to result in more
optimal outcomes on NPTL systems.

john
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