Date: Sun, 1 Jun 2008 23:57:59 +0200 From: Ed Schouten <ed@80386.nl> To: Julian Elischer <julian@elischer.org> Cc: arch@freebsd.org Subject: Re: all mutexes -> read-write locks? Message-ID: <20080601215759.GN64397@hoeg.nl> In-Reply-To: <483EE7D5.5050408@elischer.org> References: <483EE7D5.5050408@elischer.org>
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--JjsO4Ft8DCMnlCnY Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hello Julian, * Julian Elischer <julian@elischer.org> wrote: > it has been mentioned several times that through the evolution of the > locking primitives it has come to be that mutexes and exclusively =20 > acquired reader-writer locks are almost the same in terms of overhead > and that it might be a good move to define all mutexes to be > actually just that. > > this would allow people to slowly go through the system, catching low > hanging fruit by converting some of the mutex operations to reader > acquisitions wherever a writer is not required, thus reducing general =20 > system contention. > > Is there any thought on this? Last I heard jhb had confirmed that it > was feasible.. If this is going to be done, could we have mtx_* macro's pointing to the proper read/write ops? I know, it's just names, but I think most novice FreeBSD kernel hackers will almost instantaneously figure out what 'mtx' stands for. Why not make read/write locking a fundamental part of 'mtx' itself, if it doesn't introduce much overhead? --=20 Ed Schouten <ed@80386.nl> WWW: http://80386.nl/ --JjsO4Ft8DCMnlCnY Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (FreeBSD) iEYEARECAAYFAkhDG2cACgkQ52SDGA2eCwUz2gCdHhsGROTLMI2oy36oYY0279QY 5OYAn1CCk4Zu//F6gCqWSlRQswz56w+E =gmMW -----END PGP SIGNATURE----- --JjsO4Ft8DCMnlCnY--
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