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From: Andi Kleen <andi@firstfloor.org>
To: acme@kernel.org
Cc: peterz@infradead.org, jolsa@kernel.org,
	linux-kernel@vger.kernel.org, mingo@kernel.org,
	Andi Kleen <ak@linux.intel.com>
Subject: [PATCH 2/8] perf/x86: Support sysfs files depending on SMT status
Date: Thu, 19 May 2016 17:09:56 -0700
Message-ID: <1463703002-19686-3-git-send-email-andi@firstfloor.org> (raw)
In-Reply-To: <1463703002-19686-1-git-send-email-andi@firstfloor.org>

From: Andi Kleen <ak@linux.intel.com>

Add a way to show different sysfs events attributes depending on
HyperThreading is on or off. This is difficult to determine
early at boot, so we just do it dynamically when the sysfs
attribute is read.

v2:
Compute HT status only once in CPU online/offline hooks.
v3: Use topology_max_smt_threads()
v4: Change formatting. Avoid duplicated prototype.
Signed-off-by: Andi Kleen <ak@linux.intel.com>

squash! perf/x86: Support sysfs files depending on SMT status
---
 arch/x86/events/core.c       | 23 +++++++++++++++++++++++
 arch/x86/events/perf_event.h | 10 ++++++++++
 include/linux/perf_event.h   |  7 +++++++
 3 files changed, 40 insertions(+)

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 5e5e76a52f58..383657368452 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -1622,6 +1622,29 @@ ssize_t events_sysfs_show(struct device *dev, struct device_attribute *attr, cha
 }
 EXPORT_SYMBOL_GPL(events_sysfs_show);
 
+ssize_t events_ht_sysfs_show(struct device *dev, struct device_attribute *attr,
+			  char *page)
+{
+	struct perf_pmu_events_ht_attr *pmu_attr =
+		container_of(attr, struct perf_pmu_events_ht_attr, attr);
+
+	/*
+	 * Report conditional events depending on Hyper-Threading.
+	 *
+	 * This is overly conservative as usually the HT special
+	 * handling is not needed if the other CPU thread is idle.
+	 *
+	 * Note this does not (cannot) handle the case when thread
+	 * siblings are invisible, for example with virtualization
+	 * if they are owned by some other guest.  The user tool
+	 * has to re-read when a thread sibling gets onlined later.
+	 */
+	return sprintf(page, "%s",
+			topology_max_smt_threads() > 1 ?
+			pmu_attr->event_str_ht :
+			pmu_attr->event_str_noht);
+}
+
 EVENT_ATTR(cpu-cycles,			CPU_CYCLES		);
 EVENT_ATTR(instructions,		INSTRUCTIONS		);
 EVENT_ATTR(cache-references,		CACHE_REFERENCES	);
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index 8bd764df815d..e2d7285a2dac 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -668,6 +668,14 @@ static struct perf_pmu_events_attr event_attr_##v = {			\
 	.event_str	= str,						\
 };
 
+#define EVENT_ATTR_STR_HT(_name, v, noht, ht)				\
+static struct perf_pmu_events_ht_attr event_attr_##v = {		\
+	.attr		= __ATTR(_name, 0444, events_ht_sysfs_show, NULL),\
+	.id		= 0,						\
+	.event_str_noht	= noht,						\
+	.event_str_ht	= ht,						\
+}
+
 extern struct x86_pmu x86_pmu __read_mostly;
 
 static inline bool x86_pmu_has_lbr_callstack(void)
@@ -803,6 +811,8 @@ struct attribute **merge_attr(struct attribute **a, struct attribute **b);
 
 ssize_t events_sysfs_show(struct device *dev, struct device_attribute *attr,
 			  char *page);
+ssize_t events_ht_sysfs_show(struct device *dev, struct device_attribute *attr,
+			  char *page);
 
 #ifdef CONFIG_CPU_SUP_AMD
 
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 9e1c3ada91c4..43e5a345fa8a 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1304,6 +1304,13 @@ struct perf_pmu_events_attr {
 	const char *event_str;
 };
 
+struct perf_pmu_events_ht_attr {
+	struct device_attribute			attr;
+	u64 					id;
+	const char				*event_str_ht;
+	const char				*event_str_noht;
+};
+
 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
 			      char *page);
 
-- 
2.5.5

  parent reply index

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-20  0:09 Add top down metrics to perf stat Andi Kleen
2016-05-20  0:09 ` [PATCH 1/8] x86/topology: Add topology_max_smt_threads() Andi Kleen
2016-06-03 10:52   ` [tip:perf/core] " tip-bot for Andi Kleen
2016-05-20  0:09 ` Andi Kleen [this message]
2016-06-03 10:53   ` [tip:perf/core] perf/x86: Support sysfs files depending on SMT status tip-bot for Andi Kleen
2016-05-20  0:09 ` [PATCH 3/8] perf/x86/intel: Add Top Down events to Intel Core Andi Kleen
2016-06-03 10:53   ` [tip:perf/core] perf/x86/intel: Add topdown " tip-bot for Andi Kleen
2016-05-20  0:09 ` [PATCH 4/8] perf/x86/intel: Add Top Down events to Intel Atom Andi Kleen
2016-06-03 10:53   ` [tip:perf/core] perf/x86/intel: Add topdown " tip-bot for Andi Kleen
2016-05-20  0:09 ` [PATCH 5/8] perf/x86/intel: Use new topology_max_smt_threads() in HT leak workaround Andi Kleen
2016-06-03 10:54   ` [tip:perf/core] " tip-bot for Andi Kleen
2016-05-20  0:10 ` [PATCH 6/8] perf stat: Avoid fractional digits for integer scales Andi Kleen
2016-05-23 14:36   ` Arnaldo Carvalho de Melo
2016-05-20  0:10 ` [PATCH 7/8] perf stat: Basic support for TopDown in perf stat Andi Kleen
2016-05-23 14:40   ` Arnaldo Carvalho de Melo
2016-05-20  0:10 ` [PATCH 8/8] perf stat: Add computation of TopDown formulas Andi Kleen
  -- strict thread matches above, loose matches on Subject: below --
2016-05-14  1:44 Add top down metrics to perf stat Andi Kleen
2016-05-14  1:44 ` [PATCH 2/8] perf/x86: Support sysfs files depending on SMT status Andi Kleen

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