From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: Futex manpages out of date Date: Mon, 18 Jan 2010 18:03:34 +0100 Message-ID: <1263834214.4283.623.camel@laptop> References: <4B509EA1.8060509@us.ibm.com> <1263575484.4244.445.camel@laptop> <20100118164000.GK2249@machine.or.cz> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20100118164000.GK2249-DDGJ70k9y3lX+M3pkMnKjw@public.gmane.org> Sender: linux-man-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Petr Baudis Cc: drepper-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, Darren Hart , Michael Kerrisk , linux-man-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Thomas Gleixner , Ingo Molnar , Eric Dumazet , Dinakar Guniguntala , John Stultz , John Kacur List-Id: linux-man@vger.kernel.org On Mon, 2010-01-18 at 17:40 +0100, Petr Baudis wrote: > On Fri, Jan 15, 2010 at 06:11:24PM +0100, Peter Zijlstra wrote: > > On Fri, 2010-01-15 at 08:58 -0800, Darren Hart wrote: > > > The futex man-pages (2,7) from version 3.15-1 and at least a few earlier > > > versions are considerably out of date with respect to the current > > > implementation. They don't document newer op codes, such as: > > > > > > FUTEX_WAIT_BITSET > > > FUTEX_WAKE_BITSET > > > FUTEX_WAKE_OP > > > FUTEX_LOCK_PI > > > FUTEX_UNLOCK_PI > > > FUTEX_WAIT_REQUEUE_PI > > > FUTEX_CMP_REQUEUE_PI > > > > > > These new wait op codes now use absolute timeouts, while the original > > > FUTEX_WAIT uses a relative timeout. Lastly, and most importantly, glibc > > > has removed the futex() wrapper to syscall(SYS_futex, ...). With that in > > > mind, would people prefer that we simply remove the futex man-pages > > > (2,7)? > > > > A readable text about the interaction between the futex value and the > > various futex ops and how to build proper locking primitives with them > > would be helpful I think, however doing that in the form of a locking > > library (as has been suggested at KS) seems plenty fine to me. > > > > Readable code is much better than rambling English at conveying this > > stuff. > > http://people.redhat.com/drepper/futex.pdf is pretty good description, > unfortunately also outdated by now. Perhaps it would be interesting to > convert this into some kind of wiki form with Ulrich's permission? People keep saying that, but I found it highly unreadable. -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html