[PATCH v3 08/23] perf: Add AUX record

Alexander Shishkin
2014-08-11T05:29:57Z

When there's new data in the AUX space, output a record indicating its
offset and size and weather it was truncated to fix in the ring buffer.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
---
include/uapi/linux/perf_event.h | 16 ++++++++++++++++
kernel/events/core.c | 39 +++++++++++++++++++++++++++++++++++++++
kernel/events/internal.h | 3 +++
kernel/events/ring_buffer.c | 1 +
4 files changed, 59 insertions(+)

diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index 7e0967c0f5..c022c3d756 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -733,6 +733,22 @@ enum perf_event_type {
*/
PERF_RECORD_MMAP2 = 10,

+ /*
+ * Records that new data landed in the AUX buffer part.
+ *
+ * struct {
+ * struct perf_event_header header;
+ *
+ * u64 aux_offset;
+ * u64 aux_size;
+ * u8 truncated;
+ * u8 reserved[7];
+ * u64 id;
+ * u64 stream_id;
+ * };
+ */
+ PERF_RECORD_AUX = 11,
+
PERF_RECORD_MAX, /* non-ABI */
};

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 848f2af576..25aad70812 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -5443,6 +5443,45 @@ void perf_event_mmap(struct vm_area_struct *vma)
perf_event_mmap_event(&mmap_event);
}

+void perf_event_aux_event(struct perf_event *event, unsigned long head,
+ unsigned long size, bool truncated)
+{
+ struct perf_output_handle handle;
+ struct perf_sample_data sample;
+ struct perf_aux_event {
+ struct perf_event_header header;
+ u64 offset;
+ u64 size;
+ u8 truncated;
+ u8 reserved[7];
+ u64 id;
+ u64 stream_id;
+ } rec = {
+ .header = {
+ .type = PERF_RECORD_AUX,
+ .misc = 0,
+ .size = sizeof(rec),
+ },
+ .offset = head,
+ .size = size,
+ .truncated = truncated,
+ .id = primary_event_id(event),
+ .stream_id = event->id,
+ };
+ int ret;
+
+ perf_event_header__init_id(&rec.header, &sample, event);
+ ret = perf_output_begin(&handle, event, rec.header.size);
+
+ if (ret)
+ return;
+
+ perf_output_put(&handle, rec);
+ perf_event__output_id_sample(event, &handle, &sample);
+
+ perf_output_end(&handle);
+}
+
/*
* IRQ throttle logging
*/
diff --git a/kernel/events/internal.h b/kernel/events/internal.h
index b8f6c193ea..c6b2987afe 100644
--- a/kernel/events/internal.h
+++ b/kernel/events/internal.h
@@ -64,6 +64,9 @@ static inline bool rb_has_aux(struct ring_buffer *rb)
return !!rb->aux_nr_pages;
}

+void perf_event_aux_event(struct perf_event *event, unsigned long head,
+ unsigned long size, bool truncated);
+
extern void
perf_event_header__init_id(struct perf_event_header *header,
struct perf_sample_data *data,
diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index feee52077f..598c02a555 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -293,6 +293,7 @@ void perf_aux_output_end(struct perf_output_handle *handle, unsigned long size,
struct ring_buffer *rb = handle->rb;

local_add(size, &rb->aux_head);
+ perf_event_aux_event(handle->event, aux_head, size, truncated);

smp_wmb();
rb->user_page->aux_head = local_read(&rb->aux_head);
--
2.1.0.rc1