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Subject: Re: [RFC PATCH 16/23] watchdog/hardlockup: Add an HPET-based
 hardlockup detector
To: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>,
 Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@kernel.org>,
 "H. Peter Anvin" <hpa@zytor.com>
Cc: Andi Kleen <andi.kleen@intel.com>, Ashok Raj <ashok.raj@intel.com>,
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 "Ravi V. Shankar" <ravi.v.shankar@intel.com>, x86@kernel.org,
 sparclinux@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
 linux-kernel@vger.kernel.org, Jacob Pan <jacob.jun.pan@intel.com>,
 "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
 Don Zickus <dzickus@redhat.com>, Nicholas Piggin <npiggin@gmail.com>,
 Michael Ellerman <mpe@ellerman.id.au>,
 Frederic Weisbecker <frederic@kernel.org>,
 Alexei Starovoitov <ast@kernel.org>, Babu Moger <babu.moger@oracle.com>,
 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
 Masami Hiramatsu <mhiramat@kernel.org>, Peter Zijlstra
 <peterz@infradead.org>, Andrew Morton <akpm@linux-foundation.org>,
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 Colin Ian King <colin.king@canonical.com>,
 Byungchul Park <byungchul.park@lge.com>,
 "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
 "Luis R. Rodriguez" <mcgrof@kernel.org>, Waiman Long <longman@redhat.com>,
 Josh Poimboeuf <jpoimboe@redhat.com>, Davidlohr Bueso <dave@stgolabs.net>,
 Christoffer Dall <cdall@linaro.org>, Marc Zyngier <marc.zyngier@arm.com>,
 Kai-Heng Feng <kai.heng.feng@canonical.com>,
 Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
 David Rientjes <rientjes@google.com>, iommu@lists.linux-foundation.org
References: <1528851463-21140-1-git-send-email-ricardo.neri-calderon@linux.intel.com>
 <1528851463-21140-17-git-send-email-ricardo.neri-calderon@linux.intel.com>
From: Randy Dunlap <rdunlap@infradead.org>
Message-ID: <1e5bc136-4123-328a-2d2e-e6f2faef5bf4@infradead.org>
Date: Tue, 12 Jun 2018 22:23:47 -0700
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Hi,

On 06/12/2018 05:57 PM, Ricardo Neri wrote:
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index c40c7b7..6e79833 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -828,6 +828,16 @@ config HARDLOCKUP_DETECTOR_PERF
>  	bool
>  	select SOFTLOCKUP_DETECTOR
>  
> +config HARDLOCKUP_DETECTOR_HPET
> +	bool "Use HPET Timer for Hard Lockup Detection"
> +	select SOFTLOCKUP_DETECTOR
> +	select HARDLOCKUP_DETECTOR
> +	depends on HPET_TIMER && HPET
> +	help
> +	  Say y to enable a hardlockup detector that is driven by an High-Precision
> +	  Event Timer. In addition to selecting this option, the command-line
> +	  parameter nmi_watchdog option. See Documentation/admin-guide/kernel-parameters.rst

The "In addition ..." thing is a broken (incomplete) sentence.

> +
>  #
>  # Enables a timestamp based low pass filter to compensate for perf based
>  # hard lockup detection which runs too fast due to turbo modes.


-- 
~Randy