From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
To: Matthew Fornero <matthew.fornero@domain.hid>
Cc: xenomai@xenomai.org
Subject: Re: [Xenomai-help] Busy Loop Hang
Date: Thu, 04 Dec 2008 11:11:58 +0100 [thread overview]
Message-ID: <4937ACEE.9060302@domain.hid> (raw)
In-Reply-To: <843a47610812031439g309ec9b5h898e636327c841cf@domain.hid>
Matthew Fornero wrote:
> Hello,
>
> I've created the following test case to illustrate linux and any tasks
> in the secondary domain hanging while executing a busy loop on one CPU
> in an SMP system.
>
> Xenomai 2.4.5, Linux 2.6.26.5, x86_64
> Tests on quad-core AMD Opteron and dual-core Intel Core 2
> kernel booted with isolcpus=1-31
>
> Task 1 (busy loop): Priority 99, CPU 1
> polls rt_timer_tsc until a timeout value is reached (1 ms)
> increments a counter (master counter)
> updates a global variable for the elapsed time
> every four minutes, goes to sleep with rt_task_sleep
This will not work. You can not prevent linux from working during 4
minutes and hope that it continue to work normally. For a minimal
perturbation of Linux, I would advise to suspend real-time activities
every 1/HZ seconds.
--
Gilles.
prev parent reply other threads:[~2008-12-04 10:11 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-03 22:39 [Xenomai-help] Busy Loop Hang Matthew Fornero
2008-12-04 10:11 ` Gilles Chanteperdrix [this message]
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