Subject: Re: [CPUISOL] CPU isolation extensions
From: Daniel Walker <dwalker@mvista.com>
To: Max Krasnyanskiy <maxk@qualcomm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>, linux-kernel@vger.kernel.org,
       Ingo Molnar <mingo@elte.hu>, Steven Rostedt <srostedt@redhat.com>,
       Gregory Haskins <ghaskins@novell.com>, Paul Jackson <pj@sgi.com>
In-Reply-To: <479E1FD4.5040606@qualcomm.com>
References: <1201493382-29804-1-git-send-email-maxk@qualcomm.com>
	 <1201511305.6149.30.camel@lappy>  <479E1FD4.5040606@qualcomm.com>
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Date: Mon, 28 Jan 2008 15:41:45 -0800
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On Mon, 2008-01-28 at 10:32 -0800, Max Krasnyanskiy wrote:
> Just this patches. RT patches cannot achieve what I needed. Even RTAI/Xenomai can't do that.
> For example I have separate tasks with hard deadlines that must be enforced in 50usec kind 
> of range and basically no idle time whatsoever. Just to give more background it's a wireless
> basestation with SW MAC/Scheduler. Another requirement is for the SW to know precise timing
> because SW. For example there is no way we can do predictable 1-2 usec sleeps. 
> So I wrote a user-space engine that does all this, it requires full control of the CPU ie minimal
> overhead from the kernel, just IPIs for memory management and that's basically it. When my legal 
> department lets me I'll do a presentation on this stuff at Linux RT conference or something. 

What kind of hardware are you doing this on? Also I should note there is
HRT (High resolution timers) which provided microsecond level
granularity ..

Daniel

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