From: Tom Evans <tom_usenet@optusnet.com.au>
To: Lowell Gilbert <kludge@be-well.ilk.org>, xenomai@xenomai.org
Subject: Re: [Xenomai] interrupt service
Date: Fri, 27 Feb 2015 18:15:14 +1100 [thread overview]
Message-ID: <54F01982.20902@optusnet.com.au> (raw)
In-Reply-To: <44wq34cmfh.fsf@lowell-desk.lan>
On 27/02/15 09:55, Lowell Gilbert wrote:
> There isn't any useful Linux activity happening there. I just need to
> keep it from interfering much with the *other* CPU.
You may wish to check this where I remember a problem that may be related:
https://community.freescale.com/thread/328465
Points to:
http://www.arm.com/files/pdf/cachecoherencywhitepaper_6june2011.pdf
Contains:
Measurements taken on a dual core Cortex-A9 at 1GHz
with a 256K L2 cache showed that cache flushing can
take of the order of 100us.
If one core flushes the L2 cache and the other core has a miss and goes to try
and read from the L2, then I think it can be stalled for all that period. I
seem to remember from when I read this that a cache flush can stall the other
core even when it doesn't need to access L2.
A driver on the Linux core could lock the whole system up.
Tom
next prev parent reply other threads:[~2015-02-27 7:15 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-18 22:03 [Xenomai] interrupt service Lowell Gilbert
2015-02-18 22:08 ` Gilles Chanteperdrix
2015-02-19 4:44 ` Lowell Gilbert
2015-02-19 21:06 ` Lowell Gilbert
2015-02-20 19:38 ` Lowell Gilbert
2015-02-20 22:57 ` Gilles Chanteperdrix
2015-02-24 23:01 ` Lowell Gilbert
2015-02-24 23:34 ` Gilles Chanteperdrix
2015-02-25 16:22 ` Lowell Gilbert
2015-02-25 17:34 ` Philippe Gerum
2015-02-25 18:35 ` Philippe Gerum
2015-02-25 20:41 ` Lowell Gilbert
2015-02-25 21:02 ` Lowell Gilbert
2015-02-26 11:19 ` Philippe Gerum
2015-02-26 16:38 ` Lowell Gilbert
2015-02-26 17:26 ` Gilles Chanteperdrix
2015-02-26 17:56 ` Philippe Gerum
2015-02-26 19:25 ` Lowell Gilbert
2015-02-26 20:11 ` Gilles Chanteperdrix
2015-02-26 21:58 ` Lowell Gilbert
2015-02-26 22:37 ` Gilles Chanteperdrix
2015-02-26 23:12 ` Lowell Gilbert
2015-02-26 23:09 ` Philippe Gerum
2015-03-06 22:57 ` Lowell Gilbert
2015-03-06 22:58 ` Lowell Gilbert
2015-03-08 15:52 ` Gilles Chanteperdrix
2015-03-09 13:28 ` Lowell Gilbert
2015-02-26 20:24 ` Philippe Gerum
2015-02-26 22:55 ` Lowell Gilbert
2015-02-26 23:17 ` Daniele Nicolodi
2015-02-26 23:21 ` Philippe Gerum
2015-02-27 7:15 ` Tom Evans [this message]
2015-02-25 8:30 ` Philippe Gerum
2015-02-25 9:36 ` Philippe Gerum
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=54F01982.20902@optusnet.com.au \
--to=tom_usenet@optusnet.com.au \
--cc=kludge@be-well.ilk.org \
--cc=xenomai@xenomai.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.