From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
To: "Jens Köhler" <jenskxxx@googlemail.com>
Cc: xenomai@xenomai.org
Subject: Re: [Xenomai] Xenomai and normal linux application - Wait time with select() not reliable
Date: Mon, 03 Dec 2012 10:26:53 +0100 [thread overview]
Message-ID: <50BC705D.2040407@xenomai.org> (raw)
In-Reply-To: <CAL7_A_VBCVX9o4_m4DEH7iDAf423UiowDGy+FhD_VZLcfonq9g@mail.gmail.com>
On 12/03/2012 08:59 AM, Jens Köhler wrote:
> Hello,
>
> I found following additionaly out:
> One of the Xenomai tasks writes cyclically to a shared linux memory
> (its not a Xenomai shared memory). Write and read access is controlled
> by Linux semaphores. If shared memory writing is out-commented is
> there never a delay problem.
If you expect a task using a Linux semaphore to have bounded latencies,
you misunderstood the way Xenomai works.
>
> I found following explanation about Xenomai in internet. Could it
> reason for problem?
>
> "If an interrupt arrives while a Xenomai thread executes in secondary
> mode, it is not forwarded to Linux! The mechanism works as follows:
> When a Xenomai thread is executed in secondary mode, the interrupt
> shield domain is activated All Linux interrupts are stalled, until the
> Xenomai thread completes execution. The interrupts will be served
> again when Linux goes back to execute in background mode."
The interrupt shield no longer exists.
--
Gilles.
next prev parent reply other threads:[~2012-12-03 9:26 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-03 13:30 [Xenomai] Xenomai and normal linux application - Wait time with select() not reliable Jens Köhler
2012-07-03 21:53 ` Gilles Chanteperdrix
2012-07-04 8:36 ` Jens Köhler
2012-07-04 8:45 ` Gilles Chanteperdrix
2012-07-04 10:06 ` Philippe Gerum
2012-07-04 11:45 ` Jens Köhler
2012-07-04 12:04 ` Gilles Chanteperdrix
[not found] ` <CAL7_A_VQe-KGBoYq034hT=6CdJJPpwEQTs1EgDQ=325WjOfUzw@mail.gmail.com>
2012-07-04 12:57 ` Gilles Chanteperdrix
2012-07-04 13:10 ` Jens Köhler
2012-07-04 13:17 ` Jens Köhler
2012-07-04 13:22 ` Gilles Chanteperdrix
[not found] ` <CAL7_A_WTJUeWNTTra2t9veiyWMxC5VtpotocMHGPdU1v7QAxKA@mail.gmail.com>
[not found] ` <4FF44C52.6050809@xenomai.org>
[not found] ` <CAL7_A_VUC8JD9yeMnLt2iJQ0ex_at3QMhiL3cQ5CHPFh0rcJRA@mail.gmail.com>
[not found] ` <4FF585C4.1000708@xenomai.org>
2012-11-19 13:29 ` Jens Köhler
2012-11-19 13:42 ` Gilles Chanteperdrix
2012-12-03 7:59 ` Jens Köhler
2012-12-03 9:26 ` Gilles Chanteperdrix [this message]
2012-12-04 10:09 ` Jens Köhler
[not found] ` <CAL7_A_XHtj19V3gnog7_Hoer6UGxRJfoFwT0sgzQvhtARB3b9A@mail.gmail.com>
2013-01-21 12:09 ` Gilles Chanteperdrix
[not found] ` <CAL7_A_Wkjj1mTeDcEfDzPKFkQhiYeChPgC=ggVkedxqy=yaLng@mail.gmail.com>
2013-01-21 18:48 ` Gilles Chanteperdrix
2012-07-04 13:33 ` Philippe Gerum
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