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Date: Fri, 19 Aug 2016 16:09:28 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Clark Williams <williams@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>, Jon Masters <jcm@redhat.com>,
        Daniel Wagner <wagi@monom.org>, Carsten Emde <C.Emde@osadl.org>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Subject: Re: [PATCH v2 0/4] tracing: Add Hardware Latency detector tracer
Message-ID: <20160819140928.GK10121@twins.programming.kicks-ass.net>
References: <20160810135356.265780824@goodmis.org>
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On Wed, Aug 10, 2016 at 09:53:56AM -0400, Steven Rostedt wrote:
> Changes since v1:
> 
>  . Added checks for CONFIG_GENERIC_SCHED_CLOCK, and if that is set,
>    only nmi_counts will be recorded when an NMI is triggered, but not
>    the time in NMI, because the generic sched_clock is not NMI safe.
>    (suggested by Sebastian Andrzej Siewior)

So any of the platforms using GENERIC_SCHED_CLOCK _have_ NMIs ?

In any case, for those you could probably use ktime_get_mono_fast_ns().