return 0;
}
+static int lbr_callchain_add_stitched_lbr_ip(struct thread *thread,
+ struct callchain_cursor *cursor)
+{
+ struct lbr_stitch *lbr_stitch = thread->lbr_stitch;
+ struct callchain_cursor_node *cnode;
+ struct stitch_list *stitch_node;
+ int err;
+
+ list_for_each_entry(stitch_node, &lbr_stitch->lists, node) {
+ cnode = &stitch_node->cursor;
+
+ err = callchain_cursor_append(cursor, cnode->ip,
+ &cnode->ms,
+ cnode->branch,
+ &cnode->branch_flags,
+ cnode->nr_loop_iter,
+ cnode->iter_cycles,
+ cnode->branch_from,
+ cnode->srcline);
+ if (err)
+ return err;
+ }
+ return 0;
+}
+
+static struct stitch_list *get_stitch_node(struct thread *thread)
+{
+ struct lbr_stitch *lbr_stitch = thread->lbr_stitch;
+ struct stitch_list *stitch_node;
+
+ if (!list_empty(&lbr_stitch->free_lists)) {
+ stitch_node = list_first_entry(&lbr_stitch->free_lists,
+ struct stitch_list, node);
+ list_del(&stitch_node->node);
+
+ return stitch_node;
+ }
+
+ return malloc(sizeof(struct stitch_list));
+}
+
+static bool has_stitched_lbr(struct thread *thread,
+ struct perf_sample *cur,
+ struct perf_sample *prev,
+ unsigned int max_lbr,
+ bool callee)
+{
+ struct branch_stack *cur_stack = cur->branch_stack;
+ struct branch_entry *cur_entries = perf_sample__branch_entries(cur);
+ struct branch_stack *prev_stack = prev->branch_stack;
+ struct branch_entry *prev_entries = perf_sample__branch_entries(prev);
+ struct lbr_stitch *lbr_stitch = thread->lbr_stitch;
+ int i, j, nr_identical_branches = 0;
+ struct stitch_list *stitch_node;
+ u64 cur_base, distance;
+
+ if (!cur_stack || !prev_stack)
+ return false;
+
+ /* Find the physical index of the base-of-stack for current sample. */
+ cur_base = max_lbr - cur_stack->nr + cur_stack->hw_idx + 1;
+
+ distance = (prev_stack->hw_idx > cur_base) ? (prev_stack->hw_idx - cur_base) :
+ (max_lbr + prev_stack->hw_idx - cur_base);
+ /* Previous sample has shorter stack. Nothing can be stitched. */
+ if (distance + 1 > prev_stack->nr)
+ return false;
+
+ /*
+ * Check if there are identical LBRs between two samples.
+ * Identicall LBRs must have same from, to and flags values. Also,
+ * they have to be saved in the same LBR registers (same physical
+ * index).
+ *
+ * Starts from the base-of-stack of current sample.
+ */
+ for (i = distance, j = cur_stack->nr - 1; (i >= 0) && (j >= 0); i--, j--) {
+ if ((prev_entries[i].from != cur_entries[j].from) ||
+ (prev_entries[i].to != cur_entries[j].to) ||
+ (prev_entries[i].flags.value != cur_entries[j].flags.value))
+ break;
+ nr_identical_branches++;
+ }
+
+ if (!nr_identical_branches)
+ return false;
+
+ /*
+ * Save the LBRs between the base-of-stack of previous sample
+ * and the base-of-stack of current sample into lbr_stitch->lists.
+ * These LBRs will be stitched later.
+ */
+ for (i = prev_stack->nr - 1; i > (int)distance; i--) {
+
+ if (!lbr_stitch->prev_lbr_cursor[i].valid)
+ continue;
+
+ stitch_node = get_stitch_node(thread);
+ if (!stitch_node)
+ return false;
+
+ memcpy(&stitch_node->cursor, &lbr_stitch->prev_lbr_cursor[i],
+ sizeof(struct callchain_cursor_node));
+
+ if (callee)
+ list_add(&stitch_node->node, &lbr_stitch->lists);
+ else
+ list_add_tail(&stitch_node->node, &lbr_stitch->lists);
+ }
+
+ return true;
+}
+
static bool alloc_lbr_stitch(struct thread *thread, unsigned int max_lbr)
{
if (thread->lbr_stitch)
if (!thread->lbr_stitch->prev_lbr_cursor)
goto free_lbr_stitch;
+ INIT_LIST_HEAD(&thread->lbr_stitch->lists);
+ INIT_LIST_HEAD(&thread->lbr_stitch->free_lists);
+
return true;
free_lbr_stitch:
int max_stack,
unsigned int max_lbr)
{
+ bool callee = (callchain_param.order == ORDER_CALLEE);
struct ip_callchain *chain = sample->callchain;
int chain_nr = min(max_stack, (int)chain->nr), i;
struct lbr_stitch *lbr_stitch;
+ bool stitched_lbr = false;
u64 branch_from = 0;
int err;
(max_lbr > 0) && alloc_lbr_stitch(thread, max_lbr)) {
lbr_stitch = thread->lbr_stitch;
+ stitched_lbr = has_stitched_lbr(thread, sample,
+ &lbr_stitch->prev_sample,
+ max_lbr, callee);
+
+ if (!stitched_lbr && !list_empty(&lbr_stitch->lists)) {
+ list_replace_init(&lbr_stitch->lists,
+ &lbr_stitch->free_lists);
+ }
memcpy(&lbr_stitch->prev_sample, sample, sizeof(*sample));
}
- if (callchain_param.order == ORDER_CALLEE) {
+ if (callee) {
/* Add kernel ip */
err = lbr_callchain_add_kernel_ip(thread, cursor, sample,
parent, root_al, branch_from,
if (err)
goto error;
+ if (stitched_lbr) {
+ err = lbr_callchain_add_stitched_lbr_ip(thread, cursor);
+ if (err)
+ goto error;
+ }
+
} else {
+ if (stitched_lbr) {
+ err = lbr_callchain_add_stitched_lbr_ip(thread, cursor);
+ if (err)
+ goto error;
+ }
err = lbr_callchain_add_lbr_ip(thread, cursor, sample, parent,
root_al, &branch_from, false);
if (err)
projects / users / dwmw2 / linux.git / commitdiff