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Date:   Tue, 19 Jun 2018 22:01:15 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Thomas Gleixner <tglx@linutronix.de>
Cc:     Pavel Tatashin <pasha.tatashin@oracle.com>,
        steven.sistare@oracle.com, daniel.m.jordan@oracle.com,
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        heiko.carstens@de.ibm.com, john.stultz@linaro.org,
        sboyd@codeaurora.org, x86@kernel.org, linux-kernel@vger.kernel.org,
        mingo@redhat.com, hpa@zytor.com, douly.fnst@cn.fujitsu.com,
        prarit@redhat.com, feng.tang@intel.com, pmladek@suse.com,
        gnomes@lxorguk.ukuu.org.uk
Subject: Re: [PATCH v10 1/7] x86/tsc: remove tsc_disabled flag
Message-ID: <20180619200115.GH2494@hirez.programming.kicks-ass.net>
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 <alpine.DEB.2.21.1806191928040.10546@nanos.tec.linutronix.de>
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On Tue, Jun 19, 2018 at 09:12:45PM +0200, Thomas Gleixner wrote:
> On Tue, 19 Jun 2018, Peter Zijlstra wrote:
> > It does not; there is TSC usage even if you boot with notsc on. See how
> > it does not clear X86_FEATURE_TSC for instance.
> 
> Well, kinda. There is some stuff in the apic calibration which uses TSC
> independent of tsc_disabled, but that's about it.

Still, that precludes booting on hardware without TSC, so what's the
point of having notsc? I'm all for killing the thing.