Re: [PATCH v2 2/4] perf: Add function to enable perf events in kernel with ring buffer

[Alexander Shishkin]

Takao Indoh  writes:

> On 2015/09/08 18:32, Alexander Shishkin wrote:
>> Takao Indoh  writes:
>> 
>>> perf_event_create_kernel_counter is used to enable perf events in kernel
>>> without buffer for logging its events. This patch add new fucntion which
>>> enable perf events with ring buffer. Intel PT logger uses this to enable
>>> Intel PT and some associated events with its log buffer.
>> 
>> Have you seen [1] and related patches? I haven't gotten around to
>> updating them yet, but hopefully it's going to happen soon.
>> 
>> The problem is that for such api to work, this memory needs to be
>> accounted, especially when you start handling event inheritance. For
>> system crash dump it doesn't really matter, but I also need a similar
>> api for per-task core dumps, for example.
>
> I have not seen this, I'll check it. You or someone else are working on
> api for process core dump?

Yes, I am. I'll make sure to include you in the next round of patches.

Regards,
--
Alex
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Re: [PATCH v2 2/4] perf: Add function to enable perf events in kernel with ring buffer

[Alexander Shishkin]

Takao Indoh  writes:

> On 2015/09/08 18:32, Alexander Shishkin wrote:
>> Takao Indoh  writes:
>> 
>>> perf_event_create_kernel_counter is used to enable perf events in kernel
>>> without buffer for logging its events. This patch add new fucntion which
>>> enable perf events with ring buffer. Intel PT logger uses this to enable
>>> Intel PT and some associated events with its log buffer.
>> 
>> Have you seen [1] and related patches? I haven't gotten around to
>> updating them yet, but hopefully it's going to happen soon.
>> 
>> The problem is that for such api to work, this memory needs to be
>> accounted, especially when you start handling event inheritance. For
>> system crash dump it doesn't really matter, but I also need a similar
>> api for per-task core dumps, for example.
>
> I have not seen this, I'll check it. You or someone else are working on
> api for process core dump?

Yes, I am. I'll make sure to include you in the next round of patches.

Regards,
--
Alex
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
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Re: [PATCH v2 2/4] perf: Add function to enable perf events in kernel with ring buffer

[Takao Indoh]

On 2015/09/08 18:32, Alexander Shishkin wrote:
> Takao Indoh  writes:
> 
>> perf_event_create_kernel_counter is used to enable perf events in kernel
>> without buffer for logging its events. This patch add new fucntion which
>> enable perf events with ring buffer. Intel PT logger uses this to enable
>> Intel PT and some associated events with its log buffer.
> 
> Have you seen [1] and related patches? I haven't gotten around to
> updating them yet, but hopefully it's going to happen soon.
> 
> The problem is that for such api to work, this memory needs to be
> accounted, especially when you start handling event inheritance. For
> system crash dump it doesn't really matter, but I also need a similar
> api for per-task core dumps, for example.

I have not seen this, I'll check it. You or someone else are working on
api for process core dump?

Thanks,
Takao Indoh

> 
> [1] https://lkml.org/lkml/2014/10/13/290
> 
> Thanks,
> --
> Alex
> 


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Re: [PATCH v2 2/4] perf: Add function to enable perf events in kernel with ring buffer

[Alexander Shishkin]

Takao Indoh  writes:

> perf_event_create_kernel_counter is used to enable perf events in kernel
> without buffer for logging its events. This patch add new fucntion which
> enable perf events with ring buffer. Intel PT logger uses this to enable
> Intel PT and some associated events with its log buffer.

Have you seen [1] and related patches? I haven't gotten around to
updating them yet, but hopefully it's going to happen soon.

The problem is that for such api to work, this memory needs to be
accounted, especially when you start handling event inheritance. For
system crash dump it doesn't really matter, but I also need a similar
api for per-task core dumps, for example.

[1] https://lkml.org/lkml/2014/10/13/290

Thanks,
--
Alex
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH v2 2/4] perf: Add function to enable perf events in kernel with ring buffer

[Alexander Shishkin]

Takao Indoh  writes:

> perf_event_create_kernel_counter is used to enable perf events in kernel
> without buffer for logging its events. This patch add new fucntion which
> enable perf events with ring buffer. Intel PT logger uses this to enable
> Intel PT and some associated events with its log buffer.

Have you seen [1] and related patches? I haven't gotten around to
updating them yet, but hopefully it's going to happen soon.

The problem is that for such api to work, this memory needs to be
accounted, especially when you start handling event inheritance. For
system crash dump it doesn't really matter, but I also need a similar
api for per-task core dumps, for example.

[1] https://lkml.org/lkml/2014/10/13/290

Thanks,
--
Alex
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH v2 2/4] perf: Add function to enable perf events in kernel with ring buffer

[Takao Indoh]

On 2015/09/08 18:32, Alexander Shishkin wrote:
> Takao Indoh  writes:
> 
>> perf_event_create_kernel_counter is used to enable perf events in kernel
>> without buffer for logging its events. This patch add new fucntion which
>> enable perf events with ring buffer. Intel PT logger uses this to enable
>> Intel PT and some associated events with its log buffer.
> 
> Have you seen [1] and related patches? I haven't gotten around to
> updating them yet, but hopefully it's going to happen soon.
> 
> The problem is that for such api to work, this memory needs to be
> accounted, especially when you start handling event inheritance. For
> system crash dump it doesn't really matter, but I also need a similar
> api for per-task core dumps, for example.

I have not seen this, I'll check it. You or someone else are working on
api for process core dump?

Thanks,
Takao Indoh

> 
> [1] https://lkml.org/lkml/2014/10/13/290
> 
> Thanks,
> --
> Alex
> 


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
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Please read the FAQ at  http://www.tux.org/lkml/

[PATCH v2 2/4] perf: Add function to enable perf events in kernel with ring buffer

[Takao Indoh]

perf_event_create_kernel_counter is used to enable perf events in kernel
without buffer for logging its events. This patch add new fucntion which
enable perf events with ring buffer. Intel PT logger uses this to enable
Intel PT and some associated events with its log buffer.

Signed-off-by: Takao Indoh 
---
 include/linux/perf_event.h |   10 ++
 kernel/events/core.c   |   70 ---
 2 files changed, 75 insertions(+), 5 deletions(-)

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 2027809..34ada8c 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -657,6 +657,16 @@ perf_event_create_kernel_counter(struct perf_event_attr 
*attr,
struct task_struct *task,
perf_overflow_handler_t callback,
void *context);
+extern struct perf_event *
+perf_event_create_kernel_counter_with_buffer(struct perf_event_attr *attr,
+   int cpu,
+   struct task_struct *task,
+   perf_overflow_handler_t callback,
+   void *context,
+   int flags,
+   int nr_pages,
+   int nr_pages_aux,
+   struct perf_event *output_event);
 extern void perf_pmu_migrate_context(struct pmu *pmu,
int src_cpu, int dst_cpu);
 extern u64 perf_event_read_value(struct perf_event *event,
diff --git a/kernel/events/core.c b/kernel/events/core.c
index ae16867..c9d8a59 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -8356,21 +8356,33 @@ err_fd:
 }
 
 /**
- * perf_event_create_kernel_counter
+ * perf_event_create_kernel_counter_with_buffer
  *
  * @attr: attributes of the counter to create
  * @cpu: cpu in which the counter is bound
  * @task: task to profile (NULL for percpu)
+ * @overflow_handler: handler for overflow event
+ * @context: target context
+ * @flags: flags of ring buffer
+ * @nr_pages: size (number of pages) of buffer
+ * @nr_pages_aux: size (number of pages) of aux buffer
+ * @output_event: event to be attached
  */
 struct perf_event *
-perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
-struct task_struct *task,
-perf_overflow_handler_t overflow_handler,
-void *context)
+perf_event_create_kernel_counter_with_buffer(struct perf_event_attr *attr,
+   int cpu,
+   struct task_struct *task,
+   perf_overflow_handler_t overflow_handler,
+   void *context,
+   int flags,
+   int nr_pages,
+   int nr_pages_aux,
+   struct perf_event *output_event)
 {
struct perf_event_context *ctx;
struct perf_event *event;
int err;
+   struct ring_buffer *rb = NULL;
 
/*
 * Get the target context (task or percpu):
@@ -8383,6 +8395,31 @@ perf_event_create_kernel_counter(struct perf_event_attr 
*attr, int cpu,
goto err;
}
 
+   if (output_event) {
+   err = perf_event_set_output(event, output_event);
+   if (err)
+   goto err_free;
+   } else if (nr_pages) {
+   rb = rb_alloc(nr_pages,
+ event->attr.watermark ? event->attr.wakeup_watermark : 0,
+ event->cpu, flags);
+
+   if (!rb) {
+   err = -ENOMEM;
+   goto err_free;
+   }
+
+   ring_buffer_attach(event, rb);
+
+   if (nr_pages_aux) {
+   err = rb_alloc_aux(rb, event, 0, nr_pages_aux,
+  event->attr.aux_watermark, flags);
+
+   if (err)
+   goto err_free;
+   }
+   }
+
/* Mark owner so we could distinguish it from user events. */
event->owner = EVENT_OWNER_KERNEL;
 
@@ -8411,10 +8448,33 @@ perf_event_create_kernel_counter(struct perf_event_attr 
*attr, int cpu,
return event;
 
 err_free:
+   if (rb && rb->aux_pages)
+   rb_free_aux(rb);
+   if (rb)
+   rb_free(rb);
free_event(event);
 err:
return ERR_PTR(err);
 }
+EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter_with_buffer);
+
+/**
+ * perf_event_create_kernel_counter
+ *
+ * @attr: attributes of the counter to create
+ * @cpu: cpu in which the counter is bound
+ * @task: task to profile (NULL for percpu)
+ */
+struct perf_event *

[PATCH v2 2/4] perf: Add function to enable perf events in kernel with ring buffer

[Takao Indoh]

perf_event_create_kernel_counter is used to enable perf events in kernel
without buffer for logging its events. This patch add new fucntion which
enable perf events with ring buffer. Intel PT logger uses this to enable
Intel PT and some associated events with its log buffer.

Signed-off-by: Takao Indoh 
---
 include/linux/perf_event.h |   10 ++
 kernel/events/core.c   |   70 ---
 2 files changed, 75 insertions(+), 5 deletions(-)

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 2027809..34ada8c 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -657,6 +657,16 @@ perf_event_create_kernel_counter(struct perf_event_attr 
*attr,
struct task_struct *task,
perf_overflow_handler_t callback,
void *context);
+extern struct perf_event *
+perf_event_create_kernel_counter_with_buffer(struct perf_event_attr *attr,
+   int cpu,
+   struct task_struct *task,
+   perf_overflow_handler_t callback,
+   void *context,
+   int flags,
+   int nr_pages,
+   int nr_pages_aux,
+   struct perf_event *output_event);
 extern void perf_pmu_migrate_context(struct pmu *pmu,
int src_cpu, int dst_cpu);
 extern u64 perf_event_read_value(struct perf_event *event,
diff --git a/kernel/events/core.c b/kernel/events/core.c
index ae16867..c9d8a59 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -8356,21 +8356,33 @@ err_fd:
 }
 
 /**
- * perf_event_create_kernel_counter
+ * perf_event_create_kernel_counter_with_buffer
  *
  * @attr: attributes of the counter to create
  * @cpu: cpu in which the counter is bound
  * @task: task to profile (NULL for percpu)
+ * @overflow_handler: handler for overflow event
+ * @context: target context
+ * @flags: flags of ring buffer
+ * @nr_pages: size (number of pages) of buffer
+ * @nr_pages_aux: size (number of pages) of aux buffer
+ * @output_event: event to be attached
  */
 struct perf_event *
-perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
-struct task_struct *task,
-perf_overflow_handler_t overflow_handler,
-void *context)
+perf_event_create_kernel_counter_with_buffer(struct perf_event_attr *attr,
+   int cpu,
+   struct task_struct *task,
+   perf_overflow_handler_t overflow_handler,
+   void *context,
+   int flags,
+   int nr_pages,
+   int nr_pages_aux,
+   struct perf_event *output_event)
 {
struct perf_event_context *ctx;
struct perf_event *event;
int err;
+   struct ring_buffer *rb = NULL;
 
/*
 * Get the target context (task or percpu):
@@ -8383,6 +8395,31 @@ perf_event_create_kernel_counter(struct perf_event_attr 
*attr, int cpu,
goto err;
}
 
+   if (output_event) {
+   err = perf_event_set_output(event, output_event);
+   if (err)
+   goto err_free;
+   } else if (nr_pages) {
+   rb = rb_alloc(nr_pages,
+ event->attr.watermark ? event->attr.wakeup_watermark : 0,
+ event->cpu, flags);
+
+   if (!rb) {
+   err = -ENOMEM;
+   goto err_free;
+   }
+
+   ring_buffer_attach(event, rb);
+
+   if (nr_pages_aux) {
+   err = rb_alloc_aux(rb, event, 0, nr_pages_aux,
+  event->attr.aux_watermark, flags);
+
+   if (err)
+   goto err_free;
+   }
+   }
+
/* Mark owner so we could distinguish it from user events. */
event->owner = EVENT_OWNER_KERNEL;
 
@@ -8411,10 +8448,33 @@ perf_event_create_kernel_counter(struct perf_event_attr 
*attr, int cpu,
return event;
 
 err_free:
+   if (rb && rb->aux_pages)
+   rb_free_aux(rb);
+   if (rb)
+   rb_free(rb);
free_event(event);
 err:
return ERR_PTR(err);
 }
+EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter_with_buffer);
+
+/**
+ * perf_event_create_kernel_counter
+ *
+ * @attr: attributes of the counter to create
+ * @cpu: cpu in which the counter is bound
+ * @task: task to profile (NULL for percpu)
+ */
+struct perf_event *