From: Peter Zijlstra <peterz@infradead.org>
To: Dou Liyang <douly.fnst@cn.fujitsu.com>
Cc: Pasha Tatashin <pasha.tatashin@oracle.com>,
linux@armlinux.org.uk, schwidefsky@de.ibm.com,
heiko.carstens@de.ibm.com, john.stultz@linaro.org,
sboyd@codeaurora.org, x86@kernel.org,
linux-kernel@vger.kernel.org, mingo@redhat.com,
tglx@linutronix.de, hpa@zytor.com
Subject: Re: [PATCH v6 1/4] sched/clock: interface to allow timestamps early in boot
Date: Wed, 27 Sep 2017 20:05:48 +0200 [thread overview]
Message-ID: <20170927180548.GM17526@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <4a62156c-ea0f-749f-e21b-37919dfda1df@cn.fujitsu.com>
On Wed, Sep 27, 2017 at 09:52:36PM +0800, Dou Liyang wrote:
> We do not want to do that. Because, we use "notsc" to support Dynamic
> Reconfiguration[1].
>
> AFAIK, this feature enables hot-add system board which contains CPUs
> and memories. But the CPUs in different board may have different TSCs
> which are not consistent with the TSC from the existing CPUs. If we hot-add
> a board directly, the machine may happen the inconsistency of
> TSC.
>
> We make our effort to specify the same TSC value as existing one through
> hardware and firmware, but it is hard. So we recommend to specify
> "notsc" option in command line for users who want to use Dynamic
> Reconfiguration.
Oh gawd, that's horrific. And in my book a good reason to kill that
option.
next prev parent reply other threads:[~2017-09-27 18:06 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-30 18:03 [PATCH v6 0/4] Early boot time stamps for x86 Pavel Tatashin
2017-08-30 18:03 ` [PATCH v6 1/4] sched/clock: interface to allow timestamps early in boot Pavel Tatashin
2017-09-27 12:58 ` Peter Zijlstra
2017-09-27 13:10 ` Peter Zijlstra
2017-09-27 13:16 ` Pasha Tatashin
2017-09-27 13:52 ` Dou Liyang
2017-09-27 17:13 ` Pasha Tatashin
2017-09-27 18:05 ` Peter Zijlstra [this message]
2017-09-27 18:09 ` Peter Zijlstra
2017-09-28 10:03 ` Dou Liyang
2017-09-28 11:58 ` Peter Zijlstra
2017-09-28 12:12 ` Thomas Gleixner
2017-09-28 13:11 ` Pasha Tatashin
2017-09-29 15:00 ` Dou Liyang
2017-10-18 10:01 ` Dou Liyang
2017-10-18 13:38 ` Pavel Tatashin
2017-10-09 16:34 ` Pavel Tatashin
2017-10-18 21:01 ` Thomas Gleixner
2017-09-27 14:45 ` Russell King - ARM Linux
2017-09-27 17:10 ` Pasha Tatashin
2017-09-27 18:11 ` Peter Zijlstra
2017-08-30 18:03 ` [PATCH v6 2/4] time: sync read_boot_clock64() with persistent clock Pavel Tatashin
2017-08-30 18:03 ` [PATCH v6 3/4] x86/time: read_boot_clock64() implementation Pavel Tatashin
2017-08-30 18:03 ` [PATCH v6 4/4] x86/tsc: use tsc early Pavel Tatashin
[not found] ` <CALBSrqBKsojGGpe85GOg7jda-SJHLrR=pS-Pg-xa0SUg7j3OQA@mail.gmail.com>
2017-08-30 21:21 ` Fenghua Yu
2017-08-30 21:32 ` Pasha Tatashin
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