linux-kernel - Re: [RFC] Userspace RCU: (ab)using futexes to save cpu cycles and energy

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Date:	Mon, 28 Sep 2009 09:11:03 +0200
From:	Michael Schnell <mschnell@...ino.de>
To:	linux-kernel@...r.kernel.org
Subject: Re: [RFC] Userspace RCU: (ab)using futexes to save cpu cycles and
 energy

Mathieu Desnoyers wrote:
> 
> The mutex code (and usual futex users) use futex to implement mutual
> exclusion.  My goal is to send a wakeup signal to a thread waiting for
> work to perform when adding such work. But without any mutual exclusion.

Why is that different ?

if you use a normal FUTEX like pthread_mutex_...() and have the thread
block right at the start (by blocking the *UTEX before creating the
thread). Now you can wake the thread by unblocking the *UTEX.

-Michael

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