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Commit 2da33146 authored by Kan Liang's avatar Kan Liang Committed by Ingo Molnar
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perf/x86/intel/uncore: Introduce customized event_read() for client IMC uncore 



There are two free-running counters for client IMC uncore. The
customized event_init() function hard codes their index to
'UNCORE_PMC_IDX_FIXED' and 'UNCORE_PMC_IDX_FIXED + 1'.
To support the index 'UNCORE_PMC_IDX_FIXED + 1', the generic
uncore_perf_event_update is obscurely hacked.
The code quality issue will bring problems when a new counter index is
introduced into the generic code, for example, a new index for
free-running counter.

Introducing a customized event_read() function for client IMC uncore.
The customized function is copied from previous generic
uncore_pmu_event_read().
The index 'UNCORE_PMC_IDX_FIXED + 1' will be isolated for client IMC
uncore only.

Signed-off-by: default avatarKan Liang <kan.liang@intel.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: acme@kernel.org
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/1525371913-10597-1-git-send-email-kan.liang@intel.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent c52b5c5f

arch/x86/events/intel/uncore_snb.c

+31 −2
Original line number Diff line number Diff line
@@ -450,6 +450,35 @@ static void snb_uncore_imc_event_start(struct perf_event *event, int flags) 
		uncore_pmu_start_hrtimer(box);

}



static void snb_uncore_imc_event_read(struct perf_event *event)

{

	struct intel_uncore_box *box = uncore_event_to_box(event);

	u64 prev_count, new_count, delta;

	int shift;



	/*

	 * There are two free running counters in IMC.

	 * The index for the second one is hardcoded to

	 * UNCORE_PMC_IDX_FIXED + 1.

	 */

	if (event->hw.idx >= UNCORE_PMC_IDX_FIXED)

		shift = 64 - uncore_fixed_ctr_bits(box);

	else

		shift = 64 - uncore_perf_ctr_bits(box);



	/* the hrtimer might modify the previous event value */

again:

	prev_count = local64_read(&event->hw.prev_count);

	new_count = uncore_read_counter(box, event);

	if (local64_xchg(&event->hw.prev_count, new_count) != prev_count)

		goto again;



	delta = (new_count << shift) - (prev_count << shift);

	delta >>= shift;



	local64_add(delta, &event->count);

}



static void snb_uncore_imc_event_stop(struct perf_event *event, int flags)

{

	struct intel_uncore_box *box = uncore_event_to_box(event);
@@ -472,7 +501,7 @@ static void snb_uncore_imc_event_stop(struct perf_event *event, int flags) 
		 * Drain the remaining delta count out of a event

		 * that we are disabling:

		 */

		uncore_perf_event_update(box, event);

		snb_uncore_imc_event_read(event);

		hwc->state |= PERF_HES_UPTODATE;

	}

}
@@ -534,7 +563,7 @@ static struct pmu snb_uncore_imc_pmu = { 
	.del		= snb_uncore_imc_event_del,

	.start		= snb_uncore_imc_event_start,

	.stop		= snb_uncore_imc_event_stop,

	.read		= uncore_pmu_event_read,

	.read		= snb_uncore_imc_event_read,

};



static struct intel_uncore_ops snb_uncore_imc_ops = {