[PATCH V2 12/22] perf itrace: Add a heap for sorting Instruction Tracing queues

Adrian Hunter
2014-11-20T13:26:03Z

In order to process Instruction Tracing
data in time order, the queue with data
with the lowest timestamp must be
processed first. Provide a heap to
keep track of which queue that is.

As with the queues, a decoder does not have
to use the heap, but Intel BTS and Intel PT
will use it.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
tools/perf/util/itrace.c | 85 ++++++++++++++++++++++++++++++++++++++++++++++++
tools/perf/util/itrace.h | 29 +++++++++++++++++
2 files changed, 114 insertions(+)

diff --git a/tools/perf/util/itrace.c b/tools/perf/util/itrace.c
index c67bf10..b50d959 100644
--- a/tools/perf/util/itrace.c
+++ b/tools/perf/util/itrace.c
@@ -347,6 +347,91 @@ void itrace_queues__free(struct itrace_queues *queues)
queues->nr_queues = 0;
}

+static void itrace_heapify(struct itrace_heap_item *heap_array,
+ unsigned int pos, unsigned int queue_nr,
+ u64 ordinal)
+{
+ unsigned int parent;
+
+ while (pos) {
+ parent = (pos - 1) >> 1;
+ if (heap_array[parent].ordinal <= ordinal)
+ break;
+ heap_array[pos] = heap_array[parent];
+ pos = parent;
+ }
+ heap_array[pos].queue_nr = queue_nr;
+ heap_array[pos].ordinal = ordinal;
+}
+
+int itrace_heap__add(struct itrace_heap *heap, unsigned int queue_nr,
+ u64 ordinal)
+{
+ struct itrace_heap_item *heap_array;
+
+ if (queue_nr >= heap->heap_sz) {
+ unsigned int heap_sz = ITRACE_INIT_NR_QUEUES;
+
+ while (heap_sz <= queue_nr)
+ heap_sz <<= 1;
+ heap_array = realloc(heap->heap_array,
+ heap_sz * sizeof(struct itrace_heap_item));
+ if (!heap_array)
+ return -ENOMEM;
+ heap->heap_array = heap_array;
+ heap->heap_sz = heap_sz;
+ }
+
+ itrace_heapify(heap->heap_array, heap->heap_cnt++, queue_nr, ordinal);
+
+ return 0;
+}
+
+void itrace_heap__free(struct itrace_heap *heap)
+{
+ zfree(&heap->heap_array);
+ heap->heap_cnt = 0;
+ heap->heap_sz = 0;
+}
+
+void itrace_heap__pop(struct itrace_heap *heap)
+{
+ unsigned int pos, last, heap_cnt = heap->heap_cnt;
+ struct itrace_heap_item *heap_array;
+
+ if (!heap_cnt)
+ return;
+
+ heap->heap_cnt -= 1;
+
+ heap_array = heap->heap_array;
+
+ pos = 0;
+ while (1) {
+ unsigned int left, right;
+
+ left = (pos << 1) + 1;
+ if (left >= heap_cnt)
+ break;
+ right = left + 1;
+ if (right >= heap_cnt) {
+ heap_array[pos] = heap_array[left];
+ return;
+ }
+ if (heap_array[left].ordinal < heap_array[right].ordinal) {
+ heap_array[pos] = heap_array[left];
+ pos = left;
+ } else {
+ heap_array[pos] = heap_array[right];
+ pos = right;
+ }
+ }
+
+ last = heap_cnt - 1;
+ itrace_heapify(heap_array, pos, heap_array[last].queue_nr,
+ heap_array[last].ordinal);
+}
+
size_t itrace_record__info_priv_size(struct itrace_record *itr)
{
if (itr)
diff --git a/tools/perf/util/itrace.h b/tools/perf/util/itrace.h
index c357893..a7d4ad2 100644
--- a/tools/perf/util/itrace.h
+++ b/tools/perf/util/itrace.h
@@ -172,6 +172,29 @@ struct itrace_queues {
};

/**
+ * struct itrace_heap_item - element of struct itrace_heap.
+ * @queue_nr: queue number
+ * @ordinal: value used for sorting (lowest ordinal is top of the heap) expected
+ * to be a timestamp
+ */
+struct itrace_heap_item {
+ unsigned int queue_nr;
+ u64 ordinal;
+};
+
+/**
+ * struct itrace_heap - a heap suitable for sorting Instruction Tracing queues.
+ * @heap_array: the heap
+ * @heap_cnt: the number of elements in the heap
+ * @heap_sz: maximum number of elements (grows as needed)
+ */
+struct itrace_heap {
+ struct itrace_heap_item *heap_array;
+ unsigned int heap_cnt;
+ unsigned int heap_sz;
+};
+
+/**
* struct itrace_mmap - records an mmap of the itrace buffer.
* @base: address of mapped area
* @userpg: pointer to buffer's perf_event_mmap_page
@@ -280,6 +303,12 @@ void *itrace_buffer__get_data(struct itrace_buffer *buffer, int fd);
void itrace_buffer__put_data(struct itrace_buffer *buffer);
void itrace_buffer__drop_data(struct itrace_buffer *buffer);
void itrace_buffer__free(struct itrace_buffer *buffer);
+
+int itrace_heap__add(struct itrace_heap *heap, unsigned int queue_nr,
+ u64 ordinal);
+void itrace_heap__pop(struct itrace_heap *heap);
+void itrace_heap__free(struct itrace_heap *heap);
+
struct itrace_record *itrace_record__init(int *err);

int itrace_record__options(struct itrace_record *itr,
--
1.9.1