From: Lee Revell <rlrevell@joe-job.com>
To: "HOLTZ, CORBIN L. (JSC-ER) (LM)" <corbin.l.holtz1@jsc.nasa.gov>
Cc: "'linux-kernel@vger.kernel.org'" <linux-kernel@vger.kernel.org>
Subject: Re: Disable kscand/Normal?
Date: Thu, 26 Aug 2004 14:03:15 -0400 [thread overview]
Message-ID: <1093543394.5678.64.camel@krustophenia.net> (raw)
In-Reply-To: <A850C6B3EB02F044907B475259FFF56501724A18@jsc-mail08.jsc.nasa.gov>
On Wed, 2004-08-25 at 23:54, HOLTZ, CORBIN L. (JSC-ER) (LM) wrote:
> I'm currenty
> building a realtime visualization system for a Space Shuttle landing
> simulator at NASA. I'm using a small network of 5 Pentium 4 computers
> running RedHat's 2.4.20-31.9 kernel. I'm easily running 60 frames/second on
> my systems, but I'm having a problem because the kscand/Normal thread comes
> in every 25 seconds and causes me to drop a frame (very annoying). I've
> looked into the kernel source and found where the kscand threads are
> spawned. I also see where the 25 second period is coming from. What I'm
> wondering is what would happen if I disabled the kscand/Normal thread? I've
> got plenty of memory, and my process is the only thing running on the
> system. Would I eventually see problems, or would I be OK since I'm not
> running low on memory? What if I modified the kernel to allow me to
> temporarily disable the thread while my application is running (using a
> /proc file or something similar)?
You should also look into Ingo Molnar's voluntary preemption patches for
a more general way to do soft and even hard realtime with Linux. Con's
suggestion will probably solve the kscand problem but the voluntary
preemption patches provide a more general way to deal with real time
constraints. Check the LKML archives for the past few months, there has
been a lot of work in this area lately.
Lee
prev parent reply other threads:[~2004-08-26 18:18 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-08-26 3:54 Disable kscand/Normal? HOLTZ, CORBIN L. (JSC-ER) (LM)
2004-08-26 5:32 ` Con Kolivas
2004-08-26 18:03 ` Lee Revell [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1093543394.5678.64.camel@krustophenia.net \
--to=rlrevell@joe-job.com \
--cc=corbin.l.holtz1@jsc.nasa.gov \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox