Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754526AbbKXOqD (ORCPT ); Tue, 24 Nov 2015 09:46:03 -0500 Received: from casper.infradead.org ([85.118.1.10]:55270 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753319AbbKXOqA (ORCPT ); Tue, 24 Nov 2015 09:46:00 -0500 Date: Tue, 24 Nov 2015 12:45:51 -0200 From: Arnaldo Carvalho de Melo To: Namhyung Kim Cc: Frederic Weisbecker , Ingo Molnar , linux-kernel@vger.kernel.org, Andi Kleen , David Ahern , Jiri Olsa , Kan Liang , Peter Zijlstra Subject: Re: [PATCH 34/37] perf hists browser: Support flat callchains Message-ID: <20151124144551.GB30441@redhat.com> References: <1447955603-24895-1-git-send-email-acme@kernel.org> <1447955603-24895-35-git-send-email-acme@kernel.org> <20151123151647.GD3587@lerouge> <20151124052708.GB2636@sejong> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151124052708.GB2636@sejong> X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.5.20 (2009-12-10) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2814 Lines: 67 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 > > [...] > > > > > +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 majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/