Date: Wed, 28 Sep 2005 10:33:12 -0700 (PDT)
From: Christoph Lameter <clameter@engr.sgi.com>
To: Simon White <s_a_white@email.com>
cc: linux-kernel@vger.kernel.org
Subject: Re: Best Kernel Timers?
In-Reply-To: <20050928093602.DFA0B8401C@ws1-5.us4.outblaze.com>
Message-ID: <Pine.LNX.4.62.0509281031340.14338@schroedinger.engr.sgi.com>
References: <20050928093602.DFA0B8401C@ws1-5.us4.outblaze.com>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1122
Lines: 25

On Wed, 28 Sep 2005, Simon White wrote:

> Now as an alternative it is again desired that a version (although
> wont perfectly work) be available to a vanilla 2.6 kernel (possibly
> 2.4) with similiar limitations as before.  Its a shame the posix
> calls appear to not be supported in kernel for drivers so I have
> wrapped the calls for semaphores/mutexs/threads to kernel
> equivalents.

They are supported. See drivers/char/mmtimer.c for an example 
implementation.

> However I have no idea what to do for the timers.  Is there
> something suitable inkernel that would provide an async callback
> to pre-empt a realtime thread and provide better resolution than
> HZ a far amount of the time?  Or do I have to run a seperate lower
> priority busy waiting thread to wakeup the realtime one?

Yes. Provide an implementation for a posix clock like done in the mmtimer 
driver.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/