From: Joachim Achtzehnter <joachima@netacquire.com>
To: unlisted-recipients:; (no To-header on input)
Cc: linux-rt-users@vger.kernel.org
Subject: Re: Using patch-2.6.33.7.2-rt30 increases latency and CPU usage?
Date: Wed, 09 May 2012 15:13:07 -0700 [thread overview]
Message-ID: <4FAAEBF3.10907@netacquire.com> (raw)
In-Reply-To: <joepd0$e4f$1@dough.gmane.org>
Grant Edwards wrote:
> I've been loaned a clue by somebody on the OSADL mailing list: the RT
> patches are for improving _user_space_ reponse, and may do so at the
> expense of both CPU usage and interrupt latency.
The RT patches improve *worst case* latency. They are primarily intended
for applications that must *always* meet their deadlines, not merely
most of the time. In return you tend to get increased average latency as
well as reduced throughput.
> As a result, I'm better off without the RT patch if what I care
> about is interrupt latency.
Yes, if you only care about *typical* interrupt latency but don't mind
the occasional long delay.
Joachim
--
joachima@netacquire.com http://www.netacquire.com
next prev parent reply other threads:[~2012-05-09 22:55 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-09 21:18 Using patch-2.6.33.7.2-rt30 increases latency and CPU usage? Grant Edwards
2012-05-09 22:00 ` Grant Edwards
2012-05-09 22:13 ` Joachim Achtzehnter [this message]
2012-05-09 23:18 ` Grant Edwards
2012-05-10 9:46 ` Remy Bohmer
2012-05-10 13:53 ` Grant Edwards
2012-05-11 13:42 ` Remy Bohmer
2012-05-11 13:56 ` Grant Edwards
2012-05-11 18:46 ` Tim Sander
2012-05-15 17:33 ` Steven Rostedt
2012-05-15 22:58 ` Grant Edwards
2012-05-15 23:06 ` Steven Rostedt
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=4FAAEBF3.10907@netacquire.com \
--to=joachima@netacquire.com \
--cc=linux-rt-users@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;
as well as URLs for NNTP newsgroup(s).