[PATCH 0/7] perf,x86: PEBS/BTS buffer allocation changes

[PATCH 0/7] perf,x86: PEBS/BTS buffer allocation changes

[Peter Zijlstra]

Hi Stephane,

Your PEBS/BTS buffer patch failed a .config dependent build, which on its own
was rather easy to fix, but Ingo objected to the size of the patch and asked me
to rewrite in smaller increments. This patch series is the result.

What do you think?

[PATCH 1/7] perf, x86: Extract PEBS/BTS buffer free routines

[Peter Zijlstra]

[-- Attachment #1: perf-perf-event-improve-ds.patch --]
[-- Type: text/plain, Size: 1679 bytes --]

So that we may grow additional call-sites..

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
---
 arch/x86/kernel/cpu/perf_event_intel_ds.c |   30 +++++++++++++++++++++++++-----
 1 file changed, 25 insertions(+), 5 deletions(-)

Index: linux-2.6/arch/x86/kernel/cpu/perf_event_intel_ds.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ linux-2.6/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -74,6 +74,28 @@ static void fini_debug_store_on_cpu(int 
 	wrmsr_on_cpu(cpu, MSR_IA32_DS_AREA, 0, 0);
 }
 
+static void release_pebs_buffer(int cpu)
+{
+	struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
+
+	if (!ds || !x86_pmu.pebs)
+		return;
+
+	kfree((void *)(unsigned long)ds->pebs_buffer_base);
+	ds->pebs_buffer_base = 0;
+}
+
+static void release_bts_buffer(int cpu)
+{
+	struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
+
+	if (!ds || !x86_pmu.bts)
+		return;
+
+	kfree((void *)(unsigned long)ds->bts_buffer_base);
+	ds->bts_buffer_base = 0;
+}
+
 static void release_ds_buffers(void)
 {
 	int cpu;
@@ -82,7 +104,6 @@ static void release_ds_buffers(void)
 		return;
 
 	get_online_cpus();
-
 	for_each_online_cpu(cpu)
 		fini_debug_store_on_cpu(cpu);
 
@@ -92,13 +113,12 @@ static void release_ds_buffers(void)
 		if (!ds)
 			continue;
 
-		per_cpu(cpu_hw_events, cpu).ds = NULL;
+		release_pebs_buffer(cpu);
+		release_bts_buffer(cpu);
 
-		kfree((void *)(unsigned long)ds->pebs_buffer_base);
-		kfree((void *)(unsigned long)ds->bts_buffer_base);
+		per_cpu(cpu_hw_events, cpu).ds = NULL;
 		kfree(ds);
 	}
-
 	put_online_cpus();
 }
 

[PATCH 2/7] perf, x86: Extract PEBS/BTS allocation functions

[Peter Zijlstra]

[-- Attachment #1: perf-perf-event-improve-ds-2.patch --]
[-- Type: text/plain, Size: 3654 bytes --]

Mostly a cleanup.. it reduces code indentation and makes the code flow
of reserve_ds_buffers() clearer.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
---
 arch/x86/kernel/cpu/perf_event_intel_ds.c |   90 ++++++++++++++++++------------
 1 file changed, 56 insertions(+), 34 deletions(-)

Index: linux-2.6/arch/x86/kernel/cpu/perf_event_intel_ds.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ linux-2.6/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -74,6 +74,32 @@ static void fini_debug_store_on_cpu(int 
 	wrmsr_on_cpu(cpu, MSR_IA32_DS_AREA, 0, 0);
 }
 
+static int alloc_pebs_buffer(int cpu)
+{
+	struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
+	int max, thresh = 1; /* always use a single PEBS record */
+	void *buffer;
+
+	if (!x86_pmu.pebs)
+		return 0;
+
+	buffer = kzalloc(PEBS_BUFFER_SIZE, GFP_KERNEL);
+	if (unlikely(!buffer))
+		return -ENOMEM;
+
+	max = PEBS_BUFFER_SIZE / x86_pmu.pebs_record_size;
+
+	ds->pebs_buffer_base = (u64)(unsigned long)buffer;
+	ds->pebs_index = ds->pebs_buffer_base;
+	ds->pebs_absolute_maximum = ds->pebs_buffer_base +
+		max * x86_pmu.pebs_record_size;
+
+	ds->pebs_interrupt_threshold = ds->pebs_buffer_base +
+		thresh * x86_pmu.pebs_record_size;
+
+	return 0;
+}
+
 static void release_pebs_buffer(int cpu)
 {
 	struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
@@ -85,6 +111,32 @@ static void release_pebs_buffer(int cpu)
 	ds->pebs_buffer_base = 0;
 }
 
+static int alloc_bts_buffer(int cpu)
+{
+	struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
+	int max, thresh;
+	void *buffer;
+
+	if (!x86_pmu.bts)
+		return 0;
+
+	buffer = kzalloc(BTS_BUFFER_SIZE, GFP_KERNEL);
+	if (unlikely(!buffer))
+		return -ENOMEM;
+
+	max = BTS_BUFFER_SIZE / BTS_RECORD_SIZE;
+	thresh = max / 16;
+
+	ds->bts_buffer_base = (u64)(unsigned long)buffer;
+	ds->bts_index = ds->bts_buffer_base;
+	ds->bts_absolute_maximum = ds->bts_buffer_base +
+		max * BTS_RECORD_SIZE;
+	ds->bts_interrupt_threshold = ds->bts_absolute_maximum -
+		thresh * BTS_RECORD_SIZE;
+
+	return 0;
+}
+
 static void release_bts_buffer(int cpu)
 {
 	struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
@@ -133,8 +185,6 @@ static int reserve_ds_buffers(void)
 
 	for_each_possible_cpu(cpu) {
 		struct debug_store *ds;
-		void *buffer;
-		int max, thresh;
 
 		err = -ENOMEM;
 		ds = kzalloc(sizeof(*ds), GFP_KERNEL);
@@ -142,39 +192,11 @@ static int reserve_ds_buffers(void)
 			break;
 		per_cpu(cpu_hw_events, cpu).ds = ds;
 
-		if (x86_pmu.bts) {
-			buffer = kzalloc(BTS_BUFFER_SIZE, GFP_KERNEL);
-			if (unlikely(!buffer))
-				break;
-
-			max = BTS_BUFFER_SIZE / BTS_RECORD_SIZE;
-			thresh = max / 16;
-
-			ds->bts_buffer_base = (u64)(unsigned long)buffer;
-			ds->bts_index = ds->bts_buffer_base;
-			ds->bts_absolute_maximum = ds->bts_buffer_base +
-				max * BTS_RECORD_SIZE;
-			ds->bts_interrupt_threshold = ds->bts_absolute_maximum -
-				thresh * BTS_RECORD_SIZE;
-		}
+		if (alloc_bts_buffer(cpu))
+			break;
 
-		if (x86_pmu.pebs) {
-			buffer = kzalloc(PEBS_BUFFER_SIZE, GFP_KERNEL);
-			if (unlikely(!buffer))
-				break;
-
-			max = PEBS_BUFFER_SIZE / x86_pmu.pebs_record_size;
-
-			ds->pebs_buffer_base = (u64)(unsigned long)buffer;
-			ds->pebs_index = ds->pebs_buffer_base;
-			ds->pebs_absolute_maximum = ds->pebs_buffer_base +
-				max * x86_pmu.pebs_record_size;
-			/*
-			 * Always use single record PEBS
-			 */
-			ds->pebs_interrupt_threshold = ds->pebs_buffer_base +
-				x86_pmu.pebs_record_size;
-		}
+		if (alloc_pebs_buffer(cpu))
+			break;
 
 		err = 0;
 	}

[PATCH 3/7] perf, x86: Extract DS alloc/free functions

[Peter Zijlstra]

[-- Attachment #1: perf-perf-event-improve-ds-4.patch --]
[-- Type: text/plain, Size: 1809 bytes --]

Again, mostly a cleanup to unclutter the reserve_ds_buffer() code.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
---
 arch/x86/kernel/cpu/perf_event_intel_ds.c |   40 +++++++++++++++++++-----------
 1 file changed, 26 insertions(+), 14 deletions(-)

Index: linux-2.6/arch/x86/kernel/cpu/perf_event_intel_ds.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ linux-2.6/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -148,6 +148,30 @@ static void release_bts_buffer(int cpu)
 	ds->bts_buffer_base = 0;
 }
 
+static int alloc_ds_buffer(int cpu)
+{
+	struct debug_store *ds;
+
+	ds = kzalloc(sizeof(*ds), GFP_KERNEL);
+	if (unlikely(!ds))
+		return -ENOMEM;
+
+	per_cpu(cpu_hw_events, cpu).ds = ds;
+
+	return 0;
+}
+
+static void release_ds_buffer(int cpu)
+{
+	struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
+
+	if (!ds)
+		return;
+
+	per_cpu(cpu_hw_events, cpu).ds = NULL;
+	kfree(ds);
+}
+
 static void release_ds_buffers(void)
 {
 	int cpu;
@@ -160,16 +184,9 @@ static void release_ds_buffers(void)
 		fini_debug_store_on_cpu(cpu);
 
 	for_each_possible_cpu(cpu) {
-		struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
-
-		if (!ds)
-			continue;
-
 		release_pebs_buffer(cpu);
 		release_bts_buffer(cpu);
-
-		per_cpu(cpu_hw_events, cpu).ds = NULL;
-		kfree(ds);
+		release_ds_buffer(cpu);
 	}
 	put_online_cpus();
 }
@@ -184,13 +201,8 @@ static int reserve_ds_buffers(void)
 	get_online_cpus();
 
 	for_each_possible_cpu(cpu) {
-		struct debug_store *ds;
-
-		err = -ENOMEM;
-		ds = kzalloc(sizeof(*ds), GFP_KERNEL);
-		if (unlikely(!ds))
+		if (alloc_ds_buffer(cpu))
 			break;
-		per_cpu(cpu_hw_events, cpu).ds = ds;
 
 		if (alloc_bts_buffer(cpu))
 			break;

[PATCH 4/7] perf, x86: Fixup the precise_ip computation

[Peter Zijlstra]

[-- Attachment #1: perf-perf-event-improve-ds-5.patch --]
[-- Type: text/plain, Size: 867 bytes --]

In case we don't have PEBS, the LBR fixup doesn't make sense.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
---
 arch/x86/kernel/cpu/perf_event.c |    9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

Index: linux-2.6/arch/x86/kernel/cpu/perf_event.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/cpu/perf_event.c
+++ linux-2.6/arch/x86/kernel/cpu/perf_event.c
@@ -497,12 +497,13 @@ static int x86_pmu_hw_config(struct perf
 		int precise = 0;
 
 		/* Support for constant skid */
-		if (x86_pmu.pebs)
+		if (x86_pmu.pebs) {
 			precise++;
 
-		/* Support for IP fixup */
-		if (x86_pmu.lbr_nr)
-			precise++;
+			/* Support for IP fixup */
+			if (x86_pmu.lbr_nr)
+				precise++;
+		}
 
 		if (event->attr.precise_ip > precise)
 			return -EOPNOTSUPP;

[PATCH 5/7] perf, x86: Less disastrous PEBS/BTS buffer allocation failure

[Peter Zijlstra]

[-- Attachment #1: perf-perf-event-improve-ds-3.patch --]
[-- Type: text/plain, Size: 4086 bytes --]

Currently PEBS/BTS buffers are allocated when we instantiate the first
event, when this fails everything fails.

This is a problem because esp. BTS tries to allocate a rather large
buffer (64K), which can easily fail.

This patches changes the logic such that when either buffer allocation
fails, we simply don't allow events that would use these facilities,
but continue functioning for all other events.

This logic comes from a much larger patch proposed by Stephane.

Suggested-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
---
 arch/x86/kernel/cpu/perf_event.c          |    5 +-
 arch/x86/kernel/cpu/perf_event_intel_ds.c |   58 ++++++++++++++++++++++--------
 2 files changed, 47 insertions(+), 16 deletions(-)

Index: linux-2.6/arch/x86/kernel/cpu/perf_event.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/cpu/perf_event.c
+++ linux-2.6/arch/x86/kernel/cpu/perf_event.c
@@ -238,6 +238,7 @@ struct x86_pmu {
 	 * Intel DebugStore bits
 	 */
 	int		bts, pebs;
+	int		bts_active, pebs_active;
 	int		pebs_record_size;
 	void		(*drain_pebs)(struct pt_regs *regs);
 	struct event_constraint *pebs_constraints;
@@ -478,7 +479,7 @@ static int x86_setup_perfctr(struct perf
 	if ((attr->config == PERF_COUNT_HW_BRANCH_INSTRUCTIONS) &&
 	    (hwc->sample_period == 1)) {
 		/* BTS is not supported by this architecture. */
-		if (!x86_pmu.bts)
+		if (!x86_pmu.bts_active)
 			return -EOPNOTSUPP;
 
 		/* BTS is currently only allowed for user-mode. */
@@ -497,7 +498,7 @@ static int x86_pmu_hw_config(struct perf
 		int precise = 0;
 
 		/* Support for constant skid */
-		if (x86_pmu.pebs) {
+		if (x86_pmu.pebs_active) {
 			precise++;
 
 			/* Support for IP fixup */
Index: linux-2.6/arch/x86/kernel/cpu/perf_event_intel_ds.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ linux-2.6/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -193,36 +193,66 @@ static void release_ds_buffers(void)
 
 static int reserve_ds_buffers(void)
 {
-	int cpu, err = 0;
+	int bts_err = 0, pebs_err = 0;
+	int cpu;
+
+	x86_pmu.bts_active = 0;
+	x86_pmu.pebs_active = 0;
 
 	if (!x86_pmu.bts && !x86_pmu.pebs)
 		return 0;
 
+	if (!x86_pmu.bts)
+		bts_err = 1;
+
+	if (!x86_pmu.pebs)
+		pebs_err = 1;
+
 	get_online_cpus();
 
 	for_each_possible_cpu(cpu) {
-		if (alloc_ds_buffer(cpu))
-			break;
+		if (alloc_ds_buffer(cpu)) {
+			bts_err = 1;
+			pebs_err = 1;
+		}
 
-		if (alloc_bts_buffer(cpu))
-			break;
+		if (!bts_err && alloc_bts_buffer(cpu))
+			bts_err = 1;
+
+		if (!pebs_err && alloc_pebs_buffer(cpu))
+			pebs_err = 1;
 
-		if (alloc_pebs_buffer(cpu))
+		if (bts_err && pebs_err)
 			break;
+	}
+
+	if (bts_err) {
+		for_each_possible_cpu(cpu)
+			release_bts_buffer(cpu);
+	}
 
-		err = 0;
+	if (pebs_err) {
+		for_each_possible_cpu(cpu)
+			release_pebs_buffer(cpu);
 	}
 
-	if (err)
-		release_ds_buffers();
-	else {
+	if (bts_err && pebs_err) {
+		for_each_possible_cpu(cpu)
+			release_ds_buffer(cpu);
+	} else {
+		if (x86_pmu.bts && !bts_err)
+			x86_pmu.bts_active = 1;
+
+		if (x86_pmu.pebs && !pebs_err)
+			x86_pmu.pebs_active = 1;
+
 		for_each_online_cpu(cpu)
 			init_debug_store_on_cpu(cpu);
 	}
 
 	put_online_cpus();
 
-	return err;
+	return 0;
 }
 
 /*
@@ -287,7 +317,7 @@ static int intel_pmu_drain_bts_buffer(vo
 	if (!event)
 		return 0;
 
-	if (!ds)
+	if (!x86_pmu.bts_active)
 		return 0;
 
 	at  = (struct bts_record *)(unsigned long)ds->bts_buffer_base;
@@ -557,7 +587,7 @@ static void intel_pmu_drain_pebs_core(st
 	struct pebs_record_core *at, *top;
 	int n;
 
-	if (!ds || !x86_pmu.pebs)
+	if (!x86_pmu.pebs_active)
 		return;
 
 	at  = (struct pebs_record_core *)(unsigned long)ds->pebs_buffer_base;
@@ -599,7 +629,7 @@ static void intel_pmu_drain_pebs_nhm(str
 	u64 status = 0;
 	int bit, n;
 
-	if (!ds || !x86_pmu.pebs)
+	if (!x86_pmu.pebs_active)
 		return;
 
 	at  = (struct pebs_record_nhm *)(unsigned long)ds->pebs_buffer_base;

[PATCH 6/7] perf, x86: Clean up reserve_ds_buffers() signature

[Peter Zijlstra]

[-- Attachment #1: perf-perf-event-improve-ds-6.patch --]
[-- Type: text/plain, Size: 2154 bytes --]

Now that reserve_ds_buffers() never fails, change it to return
void and remove all code dealing with the error return.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
---
 arch/x86/kernel/cpu/perf_event.c          |    9 +++------
 arch/x86/kernel/cpu/perf_event_intel_ds.c |    9 +++------
 2 files changed, 6 insertions(+), 12 deletions(-)

Index: linux-2.6/arch/x86/kernel/cpu/perf_event.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/cpu/perf_event.c
+++ linux-2.6/arch/x86/kernel/cpu/perf_event.c
@@ -382,7 +382,7 @@ static void release_pmc_hardware(void) {
 
 #endif
 
-static int reserve_ds_buffers(void);
+static void reserve_ds_buffers(void);
 static void release_ds_buffers(void);
 
 static void hw_perf_event_destroy(struct perf_event *event)
@@ -546,11 +546,8 @@ static int __x86_pmu_event_init(struct p
 		if (atomic_read(&active_events) == 0) {
 			if (!reserve_pmc_hardware())
 				err = -EBUSY;
-			else {
-				err = reserve_ds_buffers();
-				if (err)
-					release_pmc_hardware();
-			}
+			else
+				reserve_ds_buffers();
 		}
 		if (!err)
 			atomic_inc(&active_events);
Index: linux-2.6/arch/x86/kernel/cpu/perf_event_intel_ds.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ linux-2.6/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -191,7 +191,7 @@ static void release_ds_buffers(void)
 	put_online_cpus();
 }
 
-static int reserve_ds_buffers(void)
+static void reserve_ds_buffers(void)
 {
 	int bts_err = 0, pebs_err = 0;
 	int cpu;
@@ -200,7 +200,7 @@ static int reserve_ds_buffers(void)
 	x86_pmu.pebs_active = 0;
 
 	if (!x86_pmu.bts && !x86_pmu.pebs)
-		return 0;
+		return;
 
 	if (!x86_pmu.bts)
 		bts_err = 1;
@@ -251,8 +251,6 @@ static int reserve_ds_buffers(void)
 	}
 
 	put_online_cpus();
-
-	return 0;
 }
 
 /*
@@ -714,9 +712,8 @@ static void intel_ds_init(void)
 
 #else /* CONFIG_CPU_SUP_INTEL */
 
-static int reserve_ds_buffers(void)
+static void reserve_ds_buffers(void)
 {
-	return 0;
 }
 
 static void release_ds_buffers(void)

[PATCH 7/7] perf, x86: Use NUMA aware allocations for PEBS/BTS/DS allocations

[Peter Zijlstra]

[-- Attachment #1: perf-perf-event-improve-ds-7.patch --]
[-- Type: text/plain, Size: 1867 bytes --]

For performance reasons its best to use NODE local memory for per-cpu buffers.

This logic comes from a much larger patch proposed by Stephane.

Suggested-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
---
 arch/x86/kernel/cpu/perf_event_intel_ds.c |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

Index: linux-2.6/arch/x86/kernel/cpu/perf_event_intel_ds.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ linux-2.6/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -77,13 +77,14 @@ static void fini_debug_store_on_cpu(int 
 static int alloc_pebs_buffer(int cpu)
 {
 	struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
+	int node = cpu_to_node(cpu);
 	int max, thresh = 1; /* always use a single PEBS record */
 	void *buffer;
 
 	if (!x86_pmu.pebs)
 		return 0;
 
-	buffer = kzalloc(PEBS_BUFFER_SIZE, GFP_KERNEL);
+	buffer = kmalloc_node(PEBS_BUFFER_SIZE, GFP_KERNEL | __GFP_ZERO, node);
 	if (unlikely(!buffer))
 		return -ENOMEM;
 
@@ -114,13 +115,14 @@ static void release_pebs_buffer(int cpu)
 static int alloc_bts_buffer(int cpu)
 {
 	struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
+	int node = cpu_to_node(cpu);
 	int max, thresh;
 	void *buffer;
 
 	if (!x86_pmu.bts)
 		return 0;
 
-	buffer = kzalloc(BTS_BUFFER_SIZE, GFP_KERNEL);
+	buffer = kmalloc_node(BTS_BUFFER_SIZE, GFP_KERNEL | __GFP_ZERO, node);
 	if (unlikely(!buffer))
 		return -ENOMEM;
 
@@ -150,9 +152,10 @@ static void release_bts_buffer(int cpu)
 
 static int alloc_ds_buffer(int cpu)
 {
+	int node = cpu_to_node(cpu);
 	struct debug_store *ds;
 
-	ds = kzalloc(sizeof(*ds), GFP_KERNEL);
+	ds = kmalloc_node(sizeof(*ds), GFP_KERNEL | __GFP_ZERO, node);
 	if (unlikely(!ds))
 		return -ENOMEM;
 

Re: [PATCH 0/7] perf,x86: PEBS/BTS buffer allocation changes

[Peter Zijlstra]

On Tue, 2010-10-19 at 15:42 +0200, Peter Zijlstra wrote:
> Hi Stephane,
> 
> Your PEBS/BTS buffer patch failed a .config dependent build, which on its own
> was rather easy to fix, but Ingo objected to the size of the patch and asked me
> to rewrite in smaller increments. This patch series is the result.
> 
> What do you think?

Stephane, can I get an ack/review tag for this?

Re: [PATCH 0/7] perf,x86: PEBS/BTS buffer allocation changes

[Stephane Eranian]

On Thu, Oct 21, 2010 at 1:35 PM, Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:
> On Tue, 2010-10-19 at 15:42 +0200, Peter Zijlstra wrote:
>> Hi Stephane,
>>
>> Your PEBS/BTS buffer patch failed a .config dependent build, which on its own
>> was rather easy to fix, but Ingo objected to the size of the patch and asked me
>> to rewrite in smaller increments. This patch series is the result.
>>
>> What do you think?
>
> Stephane, can I get an ack/review tag for this?
>
At first glance, it looks okay, I will take a closer look this afternoon
and get back to you.

Re: [PATCH 0/7] perf,x86: PEBS/BTS buffer allocation changes

[Stephane Eranian]

Works ok for me.

Acked-by: Stephane Eranian <eranian@google.com>


On Thu, Oct 21, 2010 at 1:35 PM, Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:
> On Tue, 2010-10-19 at 15:42 +0200, Peter Zijlstra wrote:
>> Hi Stephane,
>>
>> Your PEBS/BTS buffer patch failed a .config dependent build, which on its own
>> was rather easy to fix, but Ingo objected to the size of the patch and asked me
>> to rewrite in smaller increments. This patch series is the result.
>>
>> What do you think?
>
> Stephane, can I get an ack/review tag for this?
>
>

Re: [PATCH 0/7] perf,x86: PEBS/BTS buffer allocation changes

[Peter Zijlstra]

On Thu, 2010-10-21 at 16:30 +0200, Stephane Eranian wrote:
> Works ok for me.

Thanks! Will send this and your two group time accounting patches to
Ingo later today.

Re: [PATCH 0/7] perf,x86: PEBS/BTS buffer allocation changes

[Stephane Eranian]

On Thu, Oct 21, 2010 at 4:34 PM, Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:
> On Thu, 2010-10-21 at 16:30 +0200, Stephane Eranian wrote:
>> Works ok for me.
>
> Thanks! Will send this and your two group time accounting patches to
> Ingo later today.
>
Ok, once you do that, I will post a 2nd version of my patch to get
time_enabled, time_running working in samples. I got the shadow
approach to work. But I need the reverted event_sched_in() first.

[tip:perf/urgent] perf, x86: Extract PEBS/BTS buffer free routines

[tip-bot for Peter Zijlstra]

Commit-ID:  b39f88acd7d989b6b247ba87c480fc24ed71d9c5
Gitweb:     http://git.kernel.org/tip/b39f88acd7d989b6b247ba87c480fc24ed71d9c5
Author:     Peter Zijlstra <a.p.zijlstra@chello.nl>
AuthorDate: Tue, 19 Oct 2010 14:08:29 +0200
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 22 Oct 2010 14:18:24 +0200

perf, x86: Extract PEBS/BTS buffer free routines

So that we may grow additional call-sites..

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Stephane Eranian <eranian@google.com>
LKML-Reference: <20101019134808.196793164@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/kernel/cpu/perf_event_intel_ds.c |   30 ++++++++++++++++++++++++----
 1 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c
index 4977f9c..1bc1351 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -74,6 +74,28 @@ static void fini_debug_store_on_cpu(int cpu)
 	wrmsr_on_cpu(cpu, MSR_IA32_DS_AREA, 0, 0);
 }
 
+static void release_pebs_buffer(int cpu)
+{
+	struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
+
+	if (!ds || !x86_pmu.pebs)
+		return;
+
+	kfree((void *)(unsigned long)ds->pebs_buffer_base);
+	ds->pebs_buffer_base = 0;
+}
+
+static void release_bts_buffer(int cpu)
+{
+	struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
+
+	if (!ds || !x86_pmu.bts)
+		return;
+
+	kfree((void *)(unsigned long)ds->bts_buffer_base);
+	ds->bts_buffer_base = 0;
+}
+
 static void release_ds_buffers(void)
 {
 	int cpu;
@@ -82,7 +104,6 @@ static void release_ds_buffers(void)
 		return;
 
 	get_online_cpus();
-
 	for_each_online_cpu(cpu)
 		fini_debug_store_on_cpu(cpu);
 
@@ -92,13 +113,12 @@ static void release_ds_buffers(void)
 		if (!ds)
 			continue;
 
-		per_cpu(cpu_hw_events, cpu).ds = NULL;
+		release_pebs_buffer(cpu);
+		release_bts_buffer(cpu);
 
-		kfree((void *)(unsigned long)ds->pebs_buffer_base);
-		kfree((void *)(unsigned long)ds->bts_buffer_base);
+		per_cpu(cpu_hw_events, cpu).ds = NULL;
 		kfree(ds);
 	}
-
 	put_online_cpus();
 }
 

[tip:perf/urgent] perf, x86: Extract PEBS/BTS allocation functions

[tip-bot for Peter Zijlstra]

Commit-ID:  5ee25c87318fa3722026fd77089fa7ba0db8d447
Gitweb:     http://git.kernel.org/tip/5ee25c87318fa3722026fd77089fa7ba0db8d447
Author:     Peter Zijlstra <a.p.zijlstra@chello.nl>
AuthorDate: Tue, 19 Oct 2010 14:15:04 +0200
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 22 Oct 2010 14:18:25 +0200

perf, x86: Extract PEBS/BTS allocation functions

Mostly a cleanup.. it reduces code indentation and makes the code flow
of reserve_ds_buffers() clearer.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Stephane Eranian <eranian@google.com>
LKML-Reference: <20101019134808.253453452@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/kernel/cpu/perf_event_intel_ds.c |   92 ++++++++++++++++++-----------
 1 files changed, 57 insertions(+), 35 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c
index 1bc1351..14d98bd 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -74,6 +74,32 @@ static void fini_debug_store_on_cpu(int cpu)
 	wrmsr_on_cpu(cpu, MSR_IA32_DS_AREA, 0, 0);
 }
 
+static int alloc_pebs_buffer(int cpu)
+{
+	struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
+	int max, thresh = 1; /* always use a single PEBS record */
+	void *buffer;
+
+	if (!x86_pmu.pebs)
+		return 0;
+
+	buffer = kzalloc(PEBS_BUFFER_SIZE, GFP_KERNEL);
+	if (unlikely(!buffer))
+		return -ENOMEM;
+
+	max = PEBS_BUFFER_SIZE / x86_pmu.pebs_record_size;
+
+	ds->pebs_buffer_base = (u64)(unsigned long)buffer;
+	ds->pebs_index = ds->pebs_buffer_base;
+	ds->pebs_absolute_maximum = ds->pebs_buffer_base +
+		max * x86_pmu.pebs_record_size;
+
+	ds->pebs_interrupt_threshold = ds->pebs_buffer_base +
+		thresh * x86_pmu.pebs_record_size;
+
+	return 0;
+}
+
 static void release_pebs_buffer(int cpu)
 {
 	struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
@@ -85,6 +111,32 @@ static void release_pebs_buffer(int cpu)
 	ds->pebs_buffer_base = 0;
 }
 
+static int alloc_bts_buffer(int cpu)
+{
+	struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
+	int max, thresh;
+	void *buffer;
+
+	if (!x86_pmu.bts)
+		return 0;
+
+	buffer = kzalloc(BTS_BUFFER_SIZE, GFP_KERNEL);
+	if (unlikely(!buffer))
+		return -ENOMEM;
+
+	max = BTS_BUFFER_SIZE / BTS_RECORD_SIZE;
+	thresh = max / 16;
+
+	ds->bts_buffer_base = (u64)(unsigned long)buffer;
+	ds->bts_index = ds->bts_buffer_base;
+	ds->bts_absolute_maximum = ds->bts_buffer_base +
+		max * BTS_RECORD_SIZE;
+	ds->bts_interrupt_threshold = ds->bts_absolute_maximum -
+		thresh * BTS_RECORD_SIZE;
+
+	return 0;
+}
+
 static void release_bts_buffer(int cpu)
 {
 	struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
@@ -133,8 +185,6 @@ static int reserve_ds_buffers(void)
 
 	for_each_possible_cpu(cpu) {
 		struct debug_store *ds;
-		void *buffer;
-		int max, thresh;
 
 		err = -ENOMEM;
 		ds = kzalloc(sizeof(*ds), GFP_KERNEL);
@@ -142,39 +192,11 @@ static int reserve_ds_buffers(void)
 			break;
 		per_cpu(cpu_hw_events, cpu).ds = ds;
 
-		if (x86_pmu.bts) {
-			buffer = kzalloc(BTS_BUFFER_SIZE, GFP_KERNEL);
-			if (unlikely(!buffer))
-				break;
-
-			max = BTS_BUFFER_SIZE / BTS_RECORD_SIZE;
-			thresh = max / 16;
-
-			ds->bts_buffer_base = (u64)(unsigned long)buffer;
-			ds->bts_index = ds->bts_buffer_base;
-			ds->bts_absolute_maximum = ds->bts_buffer_base +
-				max * BTS_RECORD_SIZE;
-			ds->bts_interrupt_threshold = ds->bts_absolute_maximum -
-				thresh * BTS_RECORD_SIZE;
-		}
+		if (alloc_bts_buffer(cpu))
+			break;
 
-		if (x86_pmu.pebs) {
-			buffer = kzalloc(PEBS_BUFFER_SIZE, GFP_KERNEL);
-			if (unlikely(!buffer))
-				break;
-
-			max = PEBS_BUFFER_SIZE / x86_pmu.pebs_record_size;
-
-			ds->pebs_buffer_base = (u64)(unsigned long)buffer;
-			ds->pebs_index = ds->pebs_buffer_base;
-			ds->pebs_absolute_maximum = ds->pebs_buffer_base +
-				max * x86_pmu.pebs_record_size;
-			/*
-			 * Always use single record PEBS
-			 */
-			ds->pebs_interrupt_threshold = ds->pebs_buffer_base +
-				x86_pmu.pebs_record_size;
-		}
+		if (alloc_pebs_buffer(cpu))
+			break;
 
 		err = 0;
 	}

[tip:perf/urgent] perf, x86: Extract DS alloc/free functions

[tip-bot for Peter Zijlstra]

Commit-ID:  65af94baca56beb3514d6cfce782634db9cf676d
Gitweb:     http://git.kernel.org/tip/65af94baca56beb3514d6cfce782634db9cf676d
Author:     Peter Zijlstra <a.p.zijlstra@chello.nl>
AuthorDate: Tue, 19 Oct 2010 14:37:23 +0200
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 22 Oct 2010 14:18:25 +0200

perf, x86: Extract DS alloc/free functions

Again, mostly a cleanup to unclutter the reserve_ds_buffer() code.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Stephane Eranian <eranian@google.com>
LKML-Reference: <20101019134808.304495776@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/kernel/cpu/perf_event_intel_ds.c |   40 ++++++++++++++++++----------
 1 files changed, 26 insertions(+), 14 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c
index 14d98bd..3c86f4d 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -148,6 +148,30 @@ static void release_bts_buffer(int cpu)
 	ds->bts_buffer_base = 0;
 }
 
+static int alloc_ds_buffer(int cpu)
+{
+	struct debug_store *ds;
+
+	ds = kzalloc(sizeof(*ds), GFP_KERNEL);
+	if (unlikely(!ds))
+		return -ENOMEM;
+
+	per_cpu(cpu_hw_events, cpu).ds = ds;
+
+	return 0;
+}
+
+static void release_ds_buffer(int cpu)
+{
+	struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
+
+	if (!ds)
+		return;
+
+	per_cpu(cpu_hw_events, cpu).ds = NULL;
+	kfree(ds);
+}
+
 static void release_ds_buffers(void)
 {
 	int cpu;
@@ -160,16 +184,9 @@ static void release_ds_buffers(void)
 		fini_debug_store_on_cpu(cpu);
 
 	for_each_possible_cpu(cpu) {
-		struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
-
-		if (!ds)
-			continue;
-
 		release_pebs_buffer(cpu);
 		release_bts_buffer(cpu);
-
-		per_cpu(cpu_hw_events, cpu).ds = NULL;
-		kfree(ds);
+		release_ds_buffer(cpu);
 	}
 	put_online_cpus();
 }
@@ -184,13 +201,8 @@ static int reserve_ds_buffers(void)
 	get_online_cpus();
 
 	for_each_possible_cpu(cpu) {
-		struct debug_store *ds;
-
-		err = -ENOMEM;
-		ds = kzalloc(sizeof(*ds), GFP_KERNEL);
-		if (unlikely(!ds))
+		if (alloc_ds_buffer(cpu))
 			break;
-		per_cpu(cpu_hw_events, cpu).ds = ds;
 
 		if (alloc_bts_buffer(cpu))
 			break;

[tip:perf/urgent] perf, x86: Fixup the precise_ip computation

[tip-bot for Peter Zijlstra]

Commit-ID:  5553be2620ac901c21a25657bd5b59f73254e6d5
Gitweb:     http://git.kernel.org/tip/5553be2620ac901c21a25657bd5b59f73254e6d5
Author:     Peter Zijlstra <a.p.zijlstra@chello.nl>
AuthorDate: Tue, 19 Oct 2010 14:38:11 +0200
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 22 Oct 2010 14:18:25 +0200

perf, x86: Fixup the precise_ip computation

In case we don't have PEBS, the LBR fixup doesn't make sense.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Stephane Eranian <eranian@google.com>
LKML-Reference: <20101019134808.354429461@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/kernel/cpu/perf_event.c |    9 +++++----
 1 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index fe73c18..f369c53 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -497,12 +497,13 @@ static int x86_pmu_hw_config(struct perf_event *event)
 		int precise = 0;
 
 		/* Support for constant skid */
-		if (x86_pmu.pebs)
+		if (x86_pmu.pebs) {
 			precise++;
 
-		/* Support for IP fixup */
-		if (x86_pmu.lbr_nr)
-			precise++;
+			/* Support for IP fixup */
+			if (x86_pmu.lbr_nr)
+				precise++;
+		}
 
 		if (event->attr.precise_ip > precise)
 			return -EOPNOTSUPP;

[tip:perf/urgent] perf, x86: Less disastrous PEBS/BTS buffer allocation failure

[tip-bot for Peter Zijlstra]

Commit-ID:  6809b6ea73f7291f2e495d40397f1172c9caa77e
Gitweb:     http://git.kernel.org/tip/6809b6ea73f7291f2e495d40397f1172c9caa77e
Author:     Peter Zijlstra <a.p.zijlstra@chello.nl>
AuthorDate: Tue, 19 Oct 2010 14:22:50 +0200
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 22 Oct 2010 14:18:26 +0200

perf, x86: Less disastrous PEBS/BTS buffer allocation failure

Currently PEBS/BTS buffers are allocated when we instantiate the first
event, when this fails everything fails.

This is a problem because esp. BTS tries to allocate a rather large
buffer (64K), which can easily fail.

This patch changes the logic such that when either buffer allocation
fails, we simply don't allow events that would use these facilities,
but continue functioning for all other events.

This logic comes from a much larger patch proposed by Stephane.

Suggested-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Stephane Eranian <eranian@google.com>
LKML-Reference: <20101019134808.354429461@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/kernel/cpu/perf_event.c          |    5 +-
 arch/x86/kernel/cpu/perf_event_intel_ds.c |   58 ++++++++++++++++++++++-------
 2 files changed, 47 insertions(+), 16 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index f369c53..61e78f6 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -238,6 +238,7 @@ struct x86_pmu {
 	 * Intel DebugStore bits
 	 */
 	int		bts, pebs;
+	int		bts_active, pebs_active;
 	int		pebs_record_size;
 	void		(*drain_pebs)(struct pt_regs *regs);
 	struct event_constraint *pebs_constraints;
@@ -478,7 +479,7 @@ static int x86_setup_perfctr(struct perf_event *event)
 	if ((attr->config == PERF_COUNT_HW_BRANCH_INSTRUCTIONS) &&
 	    (hwc->sample_period == 1)) {
 		/* BTS is not supported by this architecture. */
-		if (!x86_pmu.bts)
+		if (!x86_pmu.bts_active)
 			return -EOPNOTSUPP;
 
 		/* BTS is currently only allowed for user-mode. */
@@ -497,7 +498,7 @@ static int x86_pmu_hw_config(struct perf_event *event)
 		int precise = 0;
 
 		/* Support for constant skid */
-		if (x86_pmu.pebs) {
+		if (x86_pmu.pebs_active) {
 			precise++;
 
 			/* Support for IP fixup */
diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c
index 3c86f4d..05c7db6 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -193,36 +193,66 @@ static void release_ds_buffers(void)
 
 static int reserve_ds_buffers(void)
 {
-	int cpu, err = 0;
+	int bts_err = 0, pebs_err = 0;
+	int cpu;
+
+	x86_pmu.bts_active = 0;
+	x86_pmu.pebs_active = 0;
 
 	if (!x86_pmu.bts && !x86_pmu.pebs)
 		return 0;
 
+	if (!x86_pmu.bts)
+		bts_err = 1;
+
+	if (!x86_pmu.pebs)
+		pebs_err = 1;
+
 	get_online_cpus();
 
 	for_each_possible_cpu(cpu) {
-		if (alloc_ds_buffer(cpu))
-			break;
+		if (alloc_ds_buffer(cpu)) {
+			bts_err = 1;
+			pebs_err = 1;
+		}
 
-		if (alloc_bts_buffer(cpu))
-			break;
+		if (!bts_err && alloc_bts_buffer(cpu))
+			bts_err = 1;
+
+		if (!pebs_err && alloc_pebs_buffer(cpu))
+			pebs_err = 1;
 
-		if (alloc_pebs_buffer(cpu))
+		if (bts_err && pebs_err)
 			break;
+	}
+
+	if (bts_err) {
+		for_each_possible_cpu(cpu)
+			release_bts_buffer(cpu);
+	}
 
-		err = 0;
+	if (pebs_err) {
+		for_each_possible_cpu(cpu)
+			release_pebs_buffer(cpu);
 	}
 
-	if (err)
-		release_ds_buffers();
-	else {
+	if (bts_err && pebs_err) {
+		for_each_possible_cpu(cpu)
+			release_ds_buffer(cpu);
+	} else {
+		if (x86_pmu.bts && !bts_err)
+			x86_pmu.bts_active = 1;
+
+		if (x86_pmu.pebs && !pebs_err)
+			x86_pmu.pebs_active = 1;
+
 		for_each_online_cpu(cpu)
 			init_debug_store_on_cpu(cpu);
 	}
 
 	put_online_cpus();
 
-	return err;
+	return 0;
 }
 
 /*
@@ -287,7 +317,7 @@ static int intel_pmu_drain_bts_buffer(void)
 	if (!event)
 		return 0;
 
-	if (!ds)
+	if (!x86_pmu.bts_active)
 		return 0;
 
 	at  = (struct bts_record *)(unsigned long)ds->bts_buffer_base;
@@ -557,7 +587,7 @@ static void intel_pmu_drain_pebs_core(struct pt_regs *iregs)
 	struct pebs_record_core *at, *top;
 	int n;
 
-	if (!ds || !x86_pmu.pebs)
+	if (!x86_pmu.pebs_active)
 		return;
 
 	at  = (struct pebs_record_core *)(unsigned long)ds->pebs_buffer_base;
@@ -599,7 +629,7 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs)
 	u64 status = 0;
 	int bit, n;
 
-	if (!ds || !x86_pmu.pebs)
+	if (!x86_pmu.pebs_active)
 		return;
 
 	at  = (struct pebs_record_nhm *)(unsigned long)ds->pebs_buffer_base;

[tip:perf/urgent] perf, x86: Clean up reserve_ds_buffers() signature

[tip-bot for Peter Zijlstra]

Commit-ID:  f80c9e304b8e8062230b0cda2c2fdd586149c771
Gitweb:     http://git.kernel.org/tip/f80c9e304b8e8062230b0cda2c2fdd586149c771
Author:     Peter Zijlstra <a.p.zijlstra@chello.nl>
AuthorDate: Tue, 19 Oct 2010 14:50:02 +0200
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 22 Oct 2010 14:18:26 +0200

perf, x86: Clean up reserve_ds_buffers() signature

Now that reserve_ds_buffers() never fails, change it to return
void and remove all code dealing with the error return.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Stephane Eranian <eranian@google.com>
LKML-Reference: <20101019134808.462621937@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/kernel/cpu/perf_event.c          |    9 +++------
 arch/x86/kernel/cpu/perf_event_intel_ds.c |    9 +++------
 2 files changed, 6 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 61e78f6..a333bf9 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -382,7 +382,7 @@ static void release_pmc_hardware(void) {}
 
 #endif
 
-static int reserve_ds_buffers(void);
+static void reserve_ds_buffers(void);
 static void release_ds_buffers(void);
 
 static void hw_perf_event_destroy(struct perf_event *event)
@@ -546,11 +546,8 @@ static int __x86_pmu_event_init(struct perf_event *event)
 		if (atomic_read(&active_events) == 0) {
 			if (!reserve_pmc_hardware())
 				err = -EBUSY;
-			else {
-				err = reserve_ds_buffers();
-				if (err)
-					release_pmc_hardware();
-			}
+			else
+				reserve_ds_buffers();
 		}
 		if (!err)
 			atomic_inc(&active_events);
diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c
index 05c7db6..8a7f81c 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -191,7 +191,7 @@ static void release_ds_buffers(void)
 	put_online_cpus();
 }
 
-static int reserve_ds_buffers(void)
+static void reserve_ds_buffers(void)
 {
 	int bts_err = 0, pebs_err = 0;
 	int cpu;
@@ -200,7 +200,7 @@ static int reserve_ds_buffers(void)
 	x86_pmu.pebs_active = 0;
 
 	if (!x86_pmu.bts && !x86_pmu.pebs)
-		return 0;
+		return;
 
 	if (!x86_pmu.bts)
 		bts_err = 1;
@@ -251,8 +251,6 @@ static int reserve_ds_buffers(void)
 	}
 
 	put_online_cpus();
-
-	return 0;
 }
 
 /*
@@ -714,9 +712,8 @@ static void intel_ds_init(void)
 
 #else /* CONFIG_CPU_SUP_INTEL */
 
-static int reserve_ds_buffers(void)
+static void reserve_ds_buffers(void)
 {
-	return 0;
 }
 
 static void release_ds_buffers(void)

[tip:perf/urgent] perf, x86: Use NUMA aware allocations for PEBS/BTS/DS allocations

[tip-bot for Peter Zijlstra]

Commit-ID:  96681fc3c9e7d1f89ab64e5eec40b6467c97680f
Gitweb:     http://git.kernel.org/tip/96681fc3c9e7d1f89ab64e5eec40b6467c97680f
Author:     Peter Zijlstra <a.p.zijlstra@chello.nl>
AuthorDate: Tue, 19 Oct 2010 14:55:33 +0200
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 22 Oct 2010 14:18:26 +0200

perf, x86: Use NUMA aware allocations for PEBS/BTS/DS allocations

For performance reasons its best to use memory node local memory for
per-cpu buffers.

This logic comes from a much larger patch proposed by Stephane.

Suggested-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Stephane Eranian <eranian@google.com>
LKML-Reference: <20101019134808.514465326@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/kernel/cpu/perf_event_intel_ds.c |    9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c
index 8a7f81c..b7dcd9f 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -77,13 +77,14 @@ static void fini_debug_store_on_cpu(int cpu)
 static int alloc_pebs_buffer(int cpu)
 {
 	struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
+	int node = cpu_to_node(cpu);
 	int max, thresh = 1; /* always use a single PEBS record */
 	void *buffer;
 
 	if (!x86_pmu.pebs)
 		return 0;
 
-	buffer = kzalloc(PEBS_BUFFER_SIZE, GFP_KERNEL);
+	buffer = kmalloc_node(PEBS_BUFFER_SIZE, GFP_KERNEL | __GFP_ZERO, node);
 	if (unlikely(!buffer))
 		return -ENOMEM;
 
@@ -114,13 +115,14 @@ static void release_pebs_buffer(int cpu)
 static int alloc_bts_buffer(int cpu)
 {
 	struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
+	int node = cpu_to_node(cpu);
 	int max, thresh;
 	void *buffer;
 
 	if (!x86_pmu.bts)
 		return 0;
 
-	buffer = kzalloc(BTS_BUFFER_SIZE, GFP_KERNEL);
+	buffer = kmalloc_node(BTS_BUFFER_SIZE, GFP_KERNEL | __GFP_ZERO, node);
 	if (unlikely(!buffer))
 		return -ENOMEM;
 
@@ -150,9 +152,10 @@ static void release_bts_buffer(int cpu)
 
 static int alloc_ds_buffer(int cpu)
 {
+	int node = cpu_to_node(cpu);
 	struct debug_store *ds;
 
-	ds = kzalloc(sizeof(*ds), GFP_KERNEL);
+	ds = kmalloc_node(sizeof(*ds), GFP_KERNEL | __GFP_ZERO, node);
 	if (unlikely(!ds))
 		return -ENOMEM;