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* [RESEND PATCH V7 1/8] perf/x86/intel/uncore: Customized event_read() for client IMC uncore
@ 2018-05-03 18:25 kan.liang
  2018-05-03 18:25 ` [RESEND PATCH V7 2/8] perf/x86/intel/uncore: Correct fixed counter index check for NHM kan.liang
                   ` (7 more replies)
  0 siblings, 8 replies; 16+ messages in thread
From: kan.liang @ 2018-05-03 18:25 UTC (permalink / raw)
  To: peterz, tglx, mingo, linux-kernel; +Cc: acme, eranian, ak, Kan Liang

From: Kan Liang <kan.liang@intel.com>

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.

Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Kan Liang <kan.liang@intel.com>
---

Changes since V6
- Refine changelog

 arch/x86/events/intel/uncore_snb.c | 33 +++++++++++++++++++++++++++++++--
 1 file changed, 31 insertions(+), 2 deletions(-)

diff --git a/arch/x86/events/intel/uncore_snb.c b/arch/x86/events/intel/uncore_snb.c
index aee5e84..df53521 100644
--- a/arch/x86/events/intel/uncore_snb.c
+++ b/arch/x86/events/intel/uncore_snb.c
@@ -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 = {
-- 
2.7.4

^ permalink raw reply related	[flat|nested] 16+ messages in thread

end of thread, other threads:[~2018-05-31 12:33 UTC | newest]

Thread overview: 16+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-05-03 18:25 [RESEND PATCH V7 1/8] perf/x86/intel/uncore: Customized event_read() for client IMC uncore kan.liang
2018-05-03 18:25 ` [RESEND PATCH V7 2/8] perf/x86/intel/uncore: Correct fixed counter index check for NHM kan.liang
2018-05-31 12:30   ` [tip:perf/core] " tip-bot for Kan Liang
2018-05-03 18:25 ` [RESEND PATCH V7 3/8] perf/x86/intel/uncore: Correct fixed counter index check in generic code kan.liang
2018-05-31 12:31   ` [tip:perf/core] " tip-bot for Kan Liang
2018-05-03 18:25 ` [RESEND PATCH V7 4/8] perf/x86/intel/uncore: Add new data structures for free running counters kan.liang
2018-05-31 12:31   ` [tip:perf/core] " tip-bot for Kan Liang
2018-05-03 18:25 ` [RESEND PATCH V7 5/8] perf/x86/intel/uncore: Add infrastructure for free running counter kan.liang
2018-05-31 12:32   ` [tip:perf/core] perf/x86/intel/uncore: Add infrastructure for free running counters tip-bot for Kan Liang
2018-05-03 18:25 ` [RESEND PATCH V7 6/8] perf/x86/intel/uncore: Support IIO free-running counters on SKX kan.liang
2018-05-31 12:32   ` [tip:perf/core] " tip-bot for Kan Liang
2018-05-03 18:25 ` [RESEND PATCH V7 7/8] perf/x86/intel/uncore: Expose uncore_pmu_event functions kan.liang
2018-05-31 12:33   ` [tip:perf/core] perf/x86/intel/uncore: Expose uncore_pmu_event*() functions tip-bot for Kan Liang
2018-05-03 18:25 ` [RESEND PATCH V7 8/8] perf/x86/intel/uncore: Clean up client IMC uncore kan.liang
2018-05-31 12:33   ` [tip:perf/core] " tip-bot for Kan Liang
2018-05-31 12:30 ` [tip:perf/core] perf/x86/intel/uncore: Introduce customized event_read() for " tip-bot for Kan Liang

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