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Date: Fri, 9 Jan 2015 13:48:24 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>, linux-kernel@vger.kernel.org,
        Robert Richter <rric@kernel.org>,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Mike Galbraith <efault@gmx.de>, Paul Mackerras <paulus@samba.org>,
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        kan.liang@intel.com, adrian.hunter@intel.com,
        markus.t.metzger@intel.com, mathieu.poirier@linaro.org,
        acme@infradead.org
Subject: Re: [PATCH v8 12/14] x86: perf: intel_pt: Intel PT PMU driver
Message-ID: <20150109124824.GL3337@twins.programming.kicks-ass.net>
References: <1415972627-37514-1-git-send-email-alexander.shishkin@linux.intel.com>
 <1415972627-37514-13-git-send-email-alexander.shishkin@linux.intel.com>
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On Fri, Nov 14, 2014 at 03:43:45PM +0200, Alexander Shishkin wrote:
> +static void pt_event_stop(struct perf_event *event, int mode)
> +{
> +	struct pt *pt = this_cpu_ptr(&pt_ctx);
> +
> +	ACCESS_ONCE(pt->handle_nmi) = 0;

Why is this needed? Will the hardware still generate interrupts if you
stop the PT thing?