Em Tue, Nov 24, 2015 at 02:27:08PM +0900, Namhyung Kim escreveu: > On Mon, Nov 23, 2015 at 04:16:48PM +0100, Frederic Weisbecker wrote: > > On Thu, Nov 19, 2015 at 02:53:20PM -0300, Arnaldo Carvalho de Melo wrote: > > > From: Namhyung Kim <[email protected]> > > [...] > > > > > +int callchain_node__make_parent_list(struct callchain_node *node) > > > +{ > > > + struct callchain_node *parent = node->parent; > > > + struct callchain_list *chain, *new; > > > + LIST_HEAD(head); > > > + > > > + while (parent) { > > > + list_for_each_entry_reverse(chain, &parent->val, list) { > > > + new = malloc(sizeof(*new)); > > > + if (new == NULL) > > > + goto out; > > > + *new = *chain; > > > + new->has_children = false; > > > + list_add_tail(&new->list, &head); > > > + } > > > + parent = parent->parent; > > > + } > > > + > > > + list_for_each_entry_safe_reverse(chain, new, &head, list) > > > + list_move_tail(&chain->list, &node->parent_val); > > > + > > > + if (!list_empty(&node->parent_val)) { > > > + chain = list_first_entry(&node->parent_val, struct > > > callchain_list, list); > > > + chain->has_children = rb_prev(&node->rb_node) || > > > rb_next(&node->rb_node); > > > + > > > + chain = list_first_entry(&node->val, struct callchain_list, > > > list); > > > + chain->has_children = false; > > > > I'm a bit puzzled with this, can't we rewind through the parents on > > printing or adding > > to the flat rbtree instead of having this parent_val field? > > Yes, this code is to simplify things on parent nodes. Maybe we could > go up to parents and print the callchain list there as you said. > > However, problem I think is how to handle 'has_children' information > on parents. That info controls folding status of each callchain. As > the info is in the struct callchain_list and flat or folded callchain > mode require the info should be in the top-most entry, I cannot share > entries in parent nodes. > > Thus I simply copied callchain lists in parents to leaf nodes. Yes, > it will consume some memory but can simplify the code.
I haven't done any measuring, but I'm noticing that 'perf top -g' is showing more warnings about not being able to process events fast enough and so ends up losing events, I tried with --max-stack 16 and it helped, this is just a heads up. Perhaps my workstation workloads are gettning deeper callchains over time, but perhaps this is the cost of processing callchains that is increasing, I need to stop and try to quantify this. We really need to look at reducing the overhead of processing callchains. - Arnaldo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
