Date: Mon, 29 Jun 2009 09:20:47 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Luming Yu <luming.yu@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>, suresh.b.siddha@intel.com,
       venkatesh.pallipadi@intel.com, Thomas Gleixner <tglx@linutronix.de>,
       "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [RFC patch] Use IPI_shortcut for lapic timer broadcast
Message-ID: <20090629072047.GB20225@elte.hu>
References: <3877989d0906282347i311eb14bp80a7c80878219c31@mail.gmail.com>
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* Luming Yu <luming.yu@gmail.com> wrote:

> Hello,
> 
> We need to use IPI shortcut to send lapic timer broadcast
> to avoid the latency of sending IPI one bye one on systems with many
> logical processors when NO_HZ is disabled.
> Without this patch,I have seen upstream kernel with RHEL 5 kernel
> config boot hang .

hm, that might be a valid optimization - but why does the lack of 
this optimization result in a hang?

	Ingo
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