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From: Andi Kleen <andi@firstfloor.org>
To: acme@kernel.org
Cc: jolsa@kernel.org, linux-kernel@vger.kernel.org,
	eranian@google.com, namhyung@kernel.org, peterz@infradead.org,
	mingo@kernel.org, Andi Kleen <ak@linux.intel.com>
Subject: [PATCH 5/9] x86, perf: Support sysfs files depending on SMT status
Date: Fri,  7 Aug 2015 18:06:21 -0700	[thread overview]
Message-ID: <1438995985-13631-6-git-send-email-andi@firstfloor.org> (raw)
In-Reply-To: <1438995985-13631-1-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.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
---
 arch/x86/kernel/cpu/perf_event.c | 34 ++++++++++++++++++++++++++++++++++
 arch/x86/kernel/cpu/perf_event.h | 10 ++++++++++
 include/linux/perf_event.h       |  7 +++++++
 3 files changed, 51 insertions(+)

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 8bac4bb..a1313ed 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -1590,6 +1590,40 @@ ssize_t events_sysfs_show(struct device *dev, struct device_attribute *attr,
 	return x86_pmu.events_sysfs_show(page, config);
 }
 
+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);
+	bool ht_on = false;
+	int cpu;
+
+	/*
+	 * Report conditional events depending on Hyper-Threading.
+	 *
+	 * Check all online CPUs if any have a thread sibling,
+	 * as perf may measure any of them.
+	 *
+	 * 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.
+	 */
+	for_each_online_cpu (cpu) {
+		ht_on = cpumask_weight(topology_sibling_cpumask(cpu)) > 1;
+		if (ht_on)
+			break;
+	}
+
+	return sprintf(page, "%s",
+			ht_on ?
+			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/kernel/cpu/perf_event.h b/arch/x86/kernel/cpu/perf_event.h
index 5edf6d8..3df86d9 100644
--- a/arch/x86/kernel/cpu/perf_event.h
+++ b/arch/x86/kernel/cpu/perf_event.h
@@ -664,6 +664,14 @@ 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)
@@ -923,6 +931,8 @@ int knc_pmu_init(void);
 
 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);
 
 static inline int is_ht_workaround_enabled(void)
 {
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 2027809..5e9ee24 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1068,6 +1068,13 @@ 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);
 
-- 
2.4.3


  parent reply	other threads:[~2015-08-08  1:06 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-08-08  1:06 Add top down metrics to perf stat Andi Kleen
2015-08-08  1:06 ` [PATCH 1/9] perf, tools: Dont stop PMU parsing on alias parse error Andi Kleen
2015-08-11 13:07   ` Jiri Olsa
2015-08-11 13:14     ` Andi Kleen
2015-08-11 13:24       ` Jiri Olsa
2015-08-11 13:40         ` Andi Kleen
2015-08-11 14:39           ` Jiri Olsa
2015-08-11 16:59             ` Andi Kleen
2015-08-08  1:06 ` [PATCH 2/9] perf, tools, stat: Support up-scaling of events Andi Kleen
2015-08-11 13:25   ` Jiri Olsa
2015-08-11 13:38     ` Andi Kleen
2015-08-11 13:54       ` Jiri Olsa
2015-08-11 17:00         ` Andi Kleen
2015-08-11 17:13           ` Jiri Olsa
2015-08-11 17:17             ` Andi Kleen
2015-08-08  1:06 ` [PATCH 3/9] perf, tools, stat: Basic support for TopDown in perf stat Andi Kleen
2015-08-08  1:06 ` [PATCH 4/9] perf, tools, stat: Add computation of TopDown formulas Andi Kleen
2015-08-08  1:06 ` Andi Kleen [this message]
2015-08-08  1:06 ` [PATCH 6/9] x86, perf: Add Top Down events to Intel Core Andi Kleen
2015-08-08  1:06 ` [PATCH 7/9] x86, perf: Add Top Down events to Intel Atom Andi Kleen
2015-08-08  1:06 ` [PATCH 8/9] perf, tools, stat: Add extra output of counter values with -v Andi Kleen
2015-08-08  1:06 ` [PATCH 9/9] perf, tools, stat: Force --per-core mode for .agg-per-core aliases Andi Kleen

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