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
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