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To: Andi Kleen <ak@suse.de>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86_64: sync_tsc fix the race (so we can boot)
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From: ebiederm@xmission.com (Eric W. Biederman)
Date: Fri, 29 Jul 2005 09:52:40 -0600
In-Reply-To: <20050729074419.GB3726@bragg.suse.de> (Andi Kleen's message of
 "Fri, 29 Jul 2005 09:44:19 +0200")
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Andi Kleen <ak@suse.de> writes:

> There are some style problems, but that can be fixed later.
>
> How did you track that nasty it down? 

I had a consistent reproducer.  

I ruled out hangs in the tsc sync code itself,
  by implementing timeouts in all of the loops.

I looked for differences with the ia64 code.

I noticed that sometimes the machine would reboot
and not just hang.

I implemented smp_call_function_single since that was what the ia64
code did.  It worked and all of my pieces of evidence just fell
together.

Eric