From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: "Koehrer Mathias (ETAS/ESS2)" <mathias.koehrer@etas.com>
Cc: "linux-rt-users@vger.kernel.org" <linux-rt-users@vger.kernel.org>,
Frederic Weisbecker <fweisbec@gmail.com>
Subject: Re: CONFIG_NO_HZ_FULL in x86 (32bit)?
Date: Fri, 11 Oct 2013 14:32:49 +0200 [thread overview]
Message-ID: <20131011123249.GG6983@linutronix.de> (raw)
In-Reply-To: <F9467A784CC48947B1D879F07370839E1E0364DC@fe20099s.ecn.etasgroup.com>
* Koehrer Mathias (ETAS/ESS2) | 2013-10-11 08:32:50 [+0000]:
>Hi all,
Hi Mathias,
>I found out that with the RT_PREEMPT patch for kernel 3.10 there is the cool feature rcu_nocbs (offload RCU callback processing) available which allows to free cores to run single real time user space applications on it.
>This feature depends on CONFIG_NO_HZ_FULL, however this is not available for x86 (32 bit).
>My question is now: Is there a way to get the rcu_nocbs running together with NO_HZ_FULL on a 32bit x86?
I *think* this is because VIRT_CPU_ACCOUNTING_GEN accounts everything in
nsec instead of jiffies and this could be very expensive on 32bit archs
doing 64bit math.
Frederic, is this everything or is there more to it?
>Thanks for any feedback
>
>Best regards
>
>Mathias
Sebastian
next prev parent reply other threads:[~2013-10-11 12:32 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-11 8:32 CONFIG_NO_HZ_FULL in x86 (32bit)? Koehrer Mathias (ETAS/ESS2)
2013-10-11 12:32 ` Sebastian Andrzej Siewior [this message]
2013-10-11 13:58 ` Frederic Weisbecker
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