When the Dispatch Trace Log data is collected along with other events
like sched tracepoint events, it needs to be correlated and present
interleaved along with these events. Perf events can be collected
parallely across the CPUs. Hence it needs to be ensured events/dtl
entries are processed in timestamp order.
An auxtrace_queue is created for each CPU. Data within each queue is in
increasing order of timestamp. Each auxtrace queue has a array/list of
auxtrace buffers. When processing the auxtrace buffer, the data is
mmapp'ed. All auxtrace queues is maintained in auxtrace heap. Each queue
has a queue number and a timestamp. The queues are sorted/added to head
based on the time stamp. So always the lowest timestamp (entries to be
processed first) is on top of the heap.
The auxtrace queue needs to be allocated and heap needs to be populated
in the sorted order of timestamp. The queue needs to be filled with data
only once via powerpc_vpadtl__update_queues() function.
powerpc_vpadtl__setup_queues() iterates through all the entries to
allocate and setup the auxtrace queue. To add to auxtrace heap, it is
required to fetch the timebase of first entry for each of the queue.
The first entry in the queue for VPA DTL PMU has the boot timebase,
frequency details which are needed to get timestamp which is required to
correlate with other events. The very next entry is the actual trace data
that provides timestamp for occurrence of DTL event. Formula used to get
the timestamp from dtl entry is:
((timbase from DTL entry - boot time) / frequency) * 1000000000
powerpc_vpadtl_decode() adds the boot time and frequency as part of
powerpc_vpadtl_queue structure so that it can be reused. Each of the
dtl_entry is of 48 bytes size. Sometimes it could happen that one buffer
is only partially processed (if the timestamp of occurrence of another
event is more than currently processed element in queue, it will move on
to next event). In order to keep track of position of buffer, additional
fields is added to powerpc_vpadtl_queue structure.
Signed-off-by: Athira Rajeev <atraj...@linux.ibm.com>
---
Changelog:
Addressed review comments from Adrian
- Moved time calculation to separate function
tools/perf/util/powerpc-vpadtl.c | 226 ++++++++++++++++++++++++++++++-
1 file changed, 223 insertions(+), 3 deletions(-)
diff --git a/tools/perf/util/powerpc-vpadtl.c b/tools/perf/util/powerpc-vpadtl.c
index 9098cbe00bfd..637abde60f44 100644
--- a/tools/perf/util/powerpc-vpadtl.c
+++ b/tools/perf/util/powerpc-vpadtl.c
@@ -10,6 +10,8 @@
#include "session.h"
#include "debug.h"
#include "powerpc-vpadtl.h"
+#include "sample.h"
+#include "tool.h"
/*
* Structure to save the auxtrace queue
@@ -38,6 +40,14 @@ struct powerpc_vpadtl_queue {
struct auxtrace_buffer *buffer;
struct thread *thread;
bool on_heap;
+ struct powerpc_vpadtl_entry *dtl;
+ u64 timestamp;
+ unsigned long pkt_len;
+ unsigned long buf_len;
+ u64 boot_tb;
+ u64 tb_freq;
+ unsigned int tb_buffer;
+ unsigned int size;
bool done;
pid_t pid;
pid_t tid;
@@ -112,6 +122,33 @@ static void powerpc_vpadtl_dump(struct powerpc_vpadtl *vpa
__maybe_unused,
}
}
+static unsigned long long powerpc_vpadtl_timestamp(struct powerpc_vpadtl_queue
*vpaq)
+{
+ struct powerpc_vpadtl_entry *record = vpaq->dtl;
+ double result, div;
+ double boot_freq;
+ unsigned long long boot_tb;
+ unsigned long long diff;
+ unsigned long long timestamp = 0;
+
+ /*
+ * Formula used to get timestamp that can be co-related with
+ * other perf events:
+ * ((timbase from DTL entry - boot time) / frequency) * 1000000000
+ */
+ if (record->timebase) {
+ boot_tb = vpaq->boot_tb;
+ boot_freq = vpaq->tb_freq;
+ diff = be64_to_cpu(record->timebase) - boot_tb;
+ div = diff / boot_freq;
+ result = div;
+ result = result * 1000000000;
+ timestamp = result;
+ }
+
+ return timestamp;
+}
+
static struct powerpc_vpadtl *session_to_vpa(struct perf_session *session)
{
return container_of(session->auxtrace, struct powerpc_vpadtl, auxtrace);
@@ -124,12 +161,195 @@ static void powerpc_vpadtl_dump_event(struct
powerpc_vpadtl *vpa, unsigned char
powerpc_vpadtl_dump(vpa, buf, len);
}
+static int powerpc_vpadtl_get_buffer(struct powerpc_vpadtl_queue *vpaq)
+{
+ struct auxtrace_buffer *buffer = vpaq->buffer;
+ struct auxtrace_queues *queues = &vpaq->vpa->queues;
+ struct auxtrace_queue *queue;
+
+ queue = &queues->queue_array[vpaq->queue_nr];
+ buffer = auxtrace_buffer__next(queue, buffer);
+
+ if (!buffer)
+ return 0;
+
+ vpaq->buffer = buffer;
+ vpaq->size = buffer->size;
+
+ /* If the aux_buffer doesn't have data associated, try to load it */
+ if (!buffer->data) {
+ /* get the file desc associated with the perf data file */
+ int fd = perf_data__fd(vpaq->vpa->session->data);
+
+ buffer->data = auxtrace_buffer__get_data(buffer, fd);
+ if (!buffer->data)
+ return -ENOMEM;
+ }
+
+ vpaq->buf_len = buffer->size;
+
+ if (buffer->size % dtl_entry_size)
+ vpaq->buf_len = buffer->size - (buffer->size % dtl_entry_size);
+
+ if (vpaq->tb_buffer != buffer->buffer_nr) {
+ vpaq->pkt_len = 0;
+ vpaq->tb_buffer = 0;
+ }
+
+ return 1;
+}
+
+/*
+ * The first entry in the queue for VPA DTL PMU has the boot timebase,
+ * frequency details which are needed to get timestamp which is required to
+ * correlate with other events. Save the boot_tb and tb_freq as part of
+ * powerpc_vpadtl_queue. The very next entry is the actual trace data to
+ * be returned.
+ */
+static int powerpc_vpadtl_decode(struct powerpc_vpadtl_queue *vpaq)
+{
+ int ret;
+ char *buf;
+ struct boottb_freq *boottb;
+
+ ret = powerpc_vpadtl_get_buffer(vpaq);
+ if (ret <= 0)
+ return ret;
+
+ boottb = (struct boottb_freq *)vpaq->buffer->data;
+ if (boottb->timebase == 0) {
+ vpaq->boot_tb = boottb->boot_tb;
+ vpaq->tb_freq = boottb->tb_freq;
+ vpaq->pkt_len += dtl_entry_size;
+ }
+
+ buf = vpaq->buffer->data;
+ buf += vpaq->pkt_len;
+ vpaq->dtl = (struct powerpc_vpadtl_entry *)buf;
+
+ vpaq->tb_buffer = vpaq->buffer->buffer_nr;
+ vpaq->buffer = NULL;
+ vpaq->buf_len = 0;
+
+ return 1;
+}
+
+static struct powerpc_vpadtl_queue *powerpc_vpadtl__alloc_queue(struct
powerpc_vpadtl *vpa,
+ unsigned int queue_nr)
+{
+ struct powerpc_vpadtl_queue *vpaq;
+
+ vpaq = zalloc(sizeof(*vpaq));
+ if (!vpaq)
+ return NULL;
+
+ vpaq->vpa = vpa;
+ vpaq->queue_nr = queue_nr;
+
+ return vpaq;
+}
+
+/*
+ * When the Dispatch Trace Log data is collected along with other events
+ * like sched tracepoint events, it needs to be correlated and present
+ * interleaved along with these events. Perf events can be collected
+ * parallely across the CPUs.
+ *
+ * An auxtrace_queue is created for each CPU. Data within each queue is in
+ * increasing order of timestamp. Allocate and setup auxtrace queues here.
+ * All auxtrace queues is maintained in auxtrace heap in the increasing order
+ * of timestamp. So always the lowest timestamp (entries to be processed first)
+ * is on top of the heap.
+ *
+ * To add to auxtrace heap, fetch the timestamp from first DTL entry
+ * for each of the queue.
+ */
+static int powerpc_vpadtl__setup_queue(struct powerpc_vpadtl *vpa,
+ struct auxtrace_queue *queue,
+ unsigned int queue_nr)
+{
+ struct powerpc_vpadtl_queue *vpaq = queue->priv;
+
+ if (list_empty(&queue->head) || vpaq)
+ return 0;
+
+ vpaq = powerpc_vpadtl__alloc_queue(vpa, queue_nr);
+ if (!vpaq)
+ return -ENOMEM;
+
+ queue->priv = vpaq;
+
+ if (queue->cpu != -1)
+ vpaq->cpu = queue->cpu;
+
+ if (!vpaq->on_heap) {
+ int ret;
+retry:
+ ret = powerpc_vpadtl_decode(vpaq);
+ if (!ret)
+ return 0;
+
+ if (ret < 0)
+ goto retry;
+
+ vpaq->timestamp = powerpc_vpadtl_timestamp(vpaq);
+
+ ret = auxtrace_heap__add(&vpa->heap, queue_nr, vpaq->timestamp);
+ if (ret)
+ return ret;
+ vpaq->on_heap = true;
+ }
+
+ return 0;
+}
+
+static int powerpc_vpadtl__setup_queues(struct powerpc_vpadtl *vpa)
+{
+ unsigned int i;
+ int ret;
+
+ for (i = 0; i < vpa->queues.nr_queues; i++) {
+ ret = powerpc_vpadtl__setup_queue(vpa,
&vpa->queues.queue_array[i], i);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static int powerpc_vpadtl__update_queues(struct powerpc_vpadtl *vpa)
+{
+ if (vpa->queues.new_data) {
+ vpa->queues.new_data = false;
+ return powerpc_vpadtl__setup_queues(vpa);
+ }
+
+ return 0;
+}
+
static int powerpc_vpadtl_process_event(struct perf_session *session
__maybe_unused,
union perf_event *event __maybe_unused,
- struct perf_sample *sample __maybe_unused,
- const struct perf_tool *tool __maybe_unused)
+ struct perf_sample *sample,
+ const struct perf_tool *tool)
{
- return 0;
+ struct powerpc_vpadtl *vpa = session_to_vpa(session);
+ int err = 0;
+
+ if (dump_trace)
+ return 0;
+
+ if (!tool->ordered_events) {
+ pr_err("VPA requires ordered events\n");
+ return -EINVAL;
+ }
+
+ if (sample->time) {
+ err = powerpc_vpadtl__update_queues(vpa);
+ if (err)
+ return err;
+ }
+
+ return err;
}
/*
--
2.47.1
