Message-ID: <1460440715.3839.101.camel@gmail.com>
Subject: Re: [PATCH RFC v0 00/12] Cyclic Scheduler Against RTC
From: Mike Galbraith <umgwanakikbuti@gmail.com>
To: "Bill Huey (hui)" <bill.huey@gmail.com>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Steven Rostedt <rostedt@goodmis.org>, linux-kernel@vger.kernel.org
Cc: Dario Faggioli <raistlin@linux.it>,
        Alessandro Zummo <a.zummo@towertech.it>,
        Thomas Gleixner <tglx@linutronix.de>,
        KY Srinivasan <kys@microsoft.com>,
        Amir Frenkel <frenkel.amir@gmail.com>, Bdale Garbee <bdale@gag.com>
Date: Tue, 12 Apr 2016 07:58:35 +0200
In-Reply-To: <1460438960-32060-1-git-send-email-bill.huey@gmail.com>
References: <1460438960-32060-1-git-send-email-bill.huey@gmail.com>
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On Mon, 2016-04-11 at 22:29 -0700, Bill Huey (hui) wrote:
> Hi,
> 
> This a crude cyclic scheduler implementation. It uses SCHED_FIFO tasks
> and runs them according to a map pattern specified by a 64 bit mask. Each
> bit corresponds to an entry into an 64 entry array of
> 'struct task_struct'. This works single core CPU 0 only for now.
> 
> Threads are 'admitted' to this map by an extension to the ioctl() via the
> of (rtc) real-time clock interface. The bit pattern then determines when
> the task will run or activate next.
> 
> The /dev/rtc interface is choosen for this purpose because of its
> accessibilty to userspace. For example, the mplayer program already use
> it as a timer source and could possibly benefit from being sync to a
> vertical retrace interrupt during decoding. Could be an OpenGL program
> needing precisely scheduler support for those same handling vertical
> retrace interrupts, low latency audio and timely handling of touch
> events amognst other uses.

Sounds like you want SGI's frame rate scheduler.

	-Mike