From: Andi Kleen <ak@suse.de>
To: Jiri Slaby <jirislaby@gmail.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: FP in kernelspace
Date: 30 Jul 2006 19:32:50 +0200 [thread overview]
Message-ID: <p733bcj3sn1.fsf@verdi.suse.de> (raw)
In-Reply-To: <44CC97A4.8050207@gmail.com>
Jiri Slaby <jirislaby@gmail.com> writes:
> I have a driver written for 2.4 + RT patches with FP support. I want
> it to work in 2.6. How to implement FP? Has anybody developped some
> "protocol" between KS and US yet? If not, could somebody point me, how
> to do it the best -- with low latency.
> The device doesn't generate irqs
Doesn't sound like something that should be supported for mainline
then.
> So 2 questions are:
> 1) howto FP in kernel
You can use kernel_fpu_begin()/_end() around the FP code in the
kernel, but the real time people will probably hate you for it because
it disables preemption.
> 3) any way to have faster ticks (up to 5000Hz)?
There are plenty of interval timers in various hardware in a typical
system that can be used. e.g. RTC is a common choice. Drawback is
that you might conflict with other users, especially in user space.
But please don't try to submit such a hack.
-Andi
next prev parent reply other threads:[~2006-07-30 17:32 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-07-30 11:28 FP in kernelspace Jiri Slaby
2006-07-30 11:31 ` Jiri Slaby
2006-07-30 14:32 ` Arjan van de Ven
2006-07-30 14:40 ` Avi Kivity
2006-07-30 14:54 ` Arjan van de Ven
2006-07-30 15:09 ` Jiri Slaby
2006-07-30 15:20 ` Arjan van de Ven
2006-07-30 15:23 ` Avi Kivity
2006-07-30 15:21 ` Avi Kivity
2006-07-30 17:34 ` Andi Kleen
2006-07-30 18:11 ` Avi Kivity
2006-07-30 18:15 ` Andi Kleen
2006-07-30 18:30 ` Avi Kivity
2006-07-30 18:17 ` Jan Engelhardt
2006-07-30 17:33 ` Andi Kleen
2006-07-30 18:18 ` Jan Engelhardt
2006-07-30 18:28 ` Avi Kivity
2006-07-30 23:11 ` Jan Engelhardt
2006-07-30 17:32 ` Andi Kleen [this message]
2006-07-31 0:33 ` Steven Rostedt
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