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From: Dave Hansen <dave.hansen@intel.com>
To: Peter Zijlstra <peterz@infradead.org>, gratian.crisan@ni.com
Cc: Thomas Gleixner <tglx@linutronix.de>,
	linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
	"H . Peter Anvin" <hpa@zytor.com>,
	x86@kernel.org, Borislav Petkov <bp@alien8.de>,
	Josh Cartwright <joshc@ni.com>,
	gratian@gmail.com
Subject: Re: [RFC PATCH] tsc: synchronize TSCs on buggy Intel Xeon E5 CPUs with offset error
Date: Fri, 13 Nov 2015 13:13:29 -0800	[thread overview]
Message-ID: <56465279.2010502@intel.com> (raw)
In-Reply-To: <20151109220232.GO17308@twins.programming.kicks-ass.net>

On 11/09/2015 02:02 PM, Peter Zijlstra wrote:
> On Mon, Nov 09, 2015 at 01:59:02PM -0600, gratian.crisan@ni.com wrote:
>> The Intel Xeon E5 processor family suffers from errata[1] BT81:
> 
>> +#ifdef CONFIG_X86_TSC
>> +	/*
>> +	 * Xeon E5 BT81 errata: TSC is not affected by warm reset.
>> +	 * The TSC registers for CPUs other than CPU0 are not cleared by a warm
>> +	 * reset resulting in a constant offset error.
>> +	 */
>> +	if ((c->x86 == 6) && (c->x86_model == 0x3f))
>> +		set_cpu_bug(c, X86_BUG_TSC_OFFSET);
>> +#endif
> 
> That's hardly a family, that's just one, Haswell server.

How did you come up with that x86_model?  The document you linked to
claimes that "Extended Model" is 0010b and "Model Number" is 1101b, so
the x86_model you are looking for should be 0x2d.


  parent reply	other threads:[~2015-11-13 21:13 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-09 19:59 [RFC PATCH] tsc: synchronize TSCs on buggy Intel Xeon E5 CPUs with offset error gratian.crisan
2015-11-09 22:02 ` Peter Zijlstra
     [not found]   ` <CAKA=qzarnUUmZb7DQE+u0Dei3F+FQNoL2bak_-dV9D9+3L=itQ@mail.gmail.com>
2015-11-10 18:27     ` Josh Hunt
2015-11-10 19:47       ` Gratian Crisan
2015-11-10 20:41         ` Josh Hunt
2015-11-11 15:41           ` Gratian Crisan
2015-11-13 20:43             ` Peter Zijlstra
2015-11-17 16:38               ` Gratian Crisan
2015-11-19 19:04               ` Gratian Crisan
2015-11-13 21:13   ` Dave Hansen [this message]
2015-11-17 16:49     ` Gratian Crisan

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