From: "Luis Claudio R. Goncalves" <lclaudio@uudg.org>
To: Christian Meier <chmeie@gmx.com>
Cc: linux-rt-users@vger.kernel.org
Subject: Re: Different priorities for different softirqs
Date: Wed, 21 Mar 2012 10:08:24 -0300 [thread overview]
Message-ID: <20120321130824.GC6028@uudg.org> (raw)
In-Reply-To: <013401cd0763$1bd93970$538bac50$@gmx.com>
On Wed, Mar 21, 2012 at 02:04:10PM +0100, Christian Meier wrote:
| Hi,
|
| On https://rt.wiki.kernel.org/articles/r/t/_/RT_PREEMPT_HOWTO_6bc9.html I
| noticed that there are different softirq kthreads for every softirq. So they
| could be prioritized differently.
| In my rt-patched kernels 3.2.11-rt20 and 3.0.24-rt42 I can only see one
| ksoftirqd instance per cpu.
|
| I did not find any hints in kernel/softirq.c where each of those kthreads is
| generated. I only see ksoftirqd.
|
| >From RT_PREEMPT_HOWTO_6bc9.html:
| ...
| 2 ? S 0:00 [softirq-high/0]
| 3 ? S 0:00 [softirq-timer/0]
| 4 ? S 0:00 [softirq-net-tx/]
| 5 ? S 0:00 [softirq-net-rx/]
| 6 ? S 0:00 [softirq-block/0]
| 7 ? S 0:00 [softirq-tasklet]
| 8 ? S 0:00 [softirq-hrtreal]
| 9 ? S 0:00 [softirq-hrtmono]
| ...
|
| How can I get these softirq different threads? Did I miss a configuration
| option?
The examples there are from older kernels (probably 2.6.18 and 2.6.23).
Several changes happened since then, to the kernels and even to the general
model of the RT patch. Among these changes, more than once softirqs have
been folded inside ksoftirqd and later unfolded. As of now, they are folded
and it seems to have helped to minimize a performance loss someone (tglx?)
observed in the early 3.0.x-rt days.
Luis
--
[ Luis Claudio R. Goncalves Bass - Gospel - RT ]
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next prev parent reply other threads:[~2012-03-21 13:11 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-21 13:04 Different priorities for different softirqs Christian Meier
2012-03-21 13:08 ` Luis Claudio R. Goncalves [this message]
2012-03-21 13:59 ` Steven Rostedt
2012-03-21 15:00 ` John Kacur
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