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Date:   Mon, 23 Jul 2018 10:28:41 +0100
From:   Alan Cox <gnomes@lxorguk.ukuu.org.uk>
To:     Pavel Tatashin <pasha.tatashin@oracle.com>
Cc:     Thomas Gleixner <tglx@linutronix.de>, peterz@infradead.org,
        Steven Sistare <steven.sistare@oracle.com>,
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        Heiko Carstens <heiko.carstens@de.ibm.com>,
        John Stultz <john.stultz@linaro.org>, sboyd@codeaurora.org,
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        mingo@redhat.com, hpa@zytor.com, douly.fnst@cn.fujitsu.com,
        prarit@redhat.com, feng.tang@intel.com,
        Petr Mladek <pmladek@suse.com>, linux-s390@vger.kernel.org,
        boris.ostrovsky@oracle.com, jgross@suse.com, pbonzini@redhat.com
Subject: Re: [PATCH v14 20/25] x86/tsc: calibrate tsc only once
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> >> If we determined tsc early in boot using one of the quick methods:
> >> from cpuid/msr/quick_pit, can we assume that frequencies of all other
> >> CPUs will be determined the same way? Or do we still have to fallback

Not on 32bit at least. You can have a mixed slot 1 SMP system such as
an ASUS BP6 with cores at say 300 and 450MHz.

Now whether you'll find any such system in the world today is another
question.

Alan