465 lines
10 KiB
C
465 lines
10 KiB
C
/*
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* Copyright (C) 2009-2010, Frederic Weisbecker <fweisbec@gmail.com>
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*
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* Handle the callchains from the stream in an ad-hoc radix tree and then
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* sort them in an rbtree.
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*
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* Using a radix for code path provides a fast retrieval and factorizes
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* memory use. Also that lets us use the paths in a hierarchical graph view.
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*
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*/
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#include <stdlib.h>
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#include <stdio.h>
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#include <stdbool.h>
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#include <errno.h>
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#include <math.h>
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#include "util.h"
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#include "callchain.h"
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bool ip_callchain__valid(struct ip_callchain *chain, const event_t *event)
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{
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unsigned int chain_size = event->header.size;
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chain_size -= (unsigned long)&event->ip.__more_data - (unsigned long)event;
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return chain->nr * sizeof(u64) <= chain_size;
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}
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#define chain_for_each_child(child, parent) \
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list_for_each_entry(child, &parent->children, brothers)
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#define chain_for_each_child_safe(child, next, parent) \
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list_for_each_entry_safe(child, next, &parent->children, brothers)
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static void
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rb_insert_callchain(struct rb_root *root, struct callchain_node *chain,
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enum chain_mode mode)
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{
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struct rb_node **p = &root->rb_node;
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struct rb_node *parent = NULL;
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struct callchain_node *rnode;
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u64 chain_cumul = cumul_hits(chain);
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while (*p) {
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u64 rnode_cumul;
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parent = *p;
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rnode = rb_entry(parent, struct callchain_node, rb_node);
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rnode_cumul = cumul_hits(rnode);
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switch (mode) {
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case CHAIN_FLAT:
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if (rnode->hit < chain->hit)
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p = &(*p)->rb_left;
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else
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p = &(*p)->rb_right;
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break;
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case CHAIN_GRAPH_ABS: /* Falldown */
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case CHAIN_GRAPH_REL:
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if (rnode_cumul < chain_cumul)
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p = &(*p)->rb_left;
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else
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p = &(*p)->rb_right;
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break;
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case CHAIN_NONE:
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default:
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break;
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}
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}
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rb_link_node(&chain->rb_node, parent, p);
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rb_insert_color(&chain->rb_node, root);
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}
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static void
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__sort_chain_flat(struct rb_root *rb_root, struct callchain_node *node,
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u64 min_hit)
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{
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struct callchain_node *child;
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chain_for_each_child(child, node)
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__sort_chain_flat(rb_root, child, min_hit);
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if (node->hit && node->hit >= min_hit)
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rb_insert_callchain(rb_root, node, CHAIN_FLAT);
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}
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/*
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* Once we get every callchains from the stream, we can now
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* sort them by hit
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*/
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static void
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sort_chain_flat(struct rb_root *rb_root, struct callchain_root *root,
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u64 min_hit, struct callchain_param *param __used)
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{
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__sort_chain_flat(rb_root, &root->node, min_hit);
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}
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static void __sort_chain_graph_abs(struct callchain_node *node,
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u64 min_hit)
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{
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struct callchain_node *child;
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node->rb_root = RB_ROOT;
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chain_for_each_child(child, node) {
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__sort_chain_graph_abs(child, min_hit);
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if (cumul_hits(child) >= min_hit)
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rb_insert_callchain(&node->rb_root, child,
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CHAIN_GRAPH_ABS);
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}
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}
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static void
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sort_chain_graph_abs(struct rb_root *rb_root, struct callchain_root *chain_root,
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u64 min_hit, struct callchain_param *param __used)
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{
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__sort_chain_graph_abs(&chain_root->node, min_hit);
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rb_root->rb_node = chain_root->node.rb_root.rb_node;
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}
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static void __sort_chain_graph_rel(struct callchain_node *node,
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double min_percent)
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{
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struct callchain_node *child;
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u64 min_hit;
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node->rb_root = RB_ROOT;
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min_hit = ceil(node->children_hit * min_percent);
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chain_for_each_child(child, node) {
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__sort_chain_graph_rel(child, min_percent);
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if (cumul_hits(child) >= min_hit)
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rb_insert_callchain(&node->rb_root, child,
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CHAIN_GRAPH_REL);
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}
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}
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static void
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sort_chain_graph_rel(struct rb_root *rb_root, struct callchain_root *chain_root,
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u64 min_hit __used, struct callchain_param *param)
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{
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__sort_chain_graph_rel(&chain_root->node, param->min_percent / 100.0);
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rb_root->rb_node = chain_root->node.rb_root.rb_node;
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}
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int register_callchain_param(struct callchain_param *param)
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{
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switch (param->mode) {
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case CHAIN_GRAPH_ABS:
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param->sort = sort_chain_graph_abs;
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break;
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case CHAIN_GRAPH_REL:
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param->sort = sort_chain_graph_rel;
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break;
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case CHAIN_FLAT:
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param->sort = sort_chain_flat;
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break;
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case CHAIN_NONE:
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default:
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return -1;
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}
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return 0;
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}
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/*
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* Create a child for a parent. If inherit_children, then the new child
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* will become the new parent of it's parent children
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*/
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static struct callchain_node *
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create_child(struct callchain_node *parent, bool inherit_children)
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{
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struct callchain_node *new;
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new = zalloc(sizeof(*new));
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if (!new) {
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perror("not enough memory to create child for code path tree");
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return NULL;
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}
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new->parent = parent;
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INIT_LIST_HEAD(&new->children);
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INIT_LIST_HEAD(&new->val);
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if (inherit_children) {
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struct callchain_node *next;
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list_splice(&parent->children, &new->children);
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INIT_LIST_HEAD(&parent->children);
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chain_for_each_child(next, new)
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next->parent = new;
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}
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list_add_tail(&new->brothers, &parent->children);
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return new;
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}
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struct resolved_ip {
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u64 ip;
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struct map_symbol ms;
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};
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struct resolved_chain {
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u64 nr;
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struct resolved_ip ips[0];
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};
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/*
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* Fill the node with callchain values
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*/
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static void
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fill_node(struct callchain_node *node, struct resolved_chain *chain, int start)
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{
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unsigned int i;
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for (i = start; i < chain->nr; i++) {
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struct callchain_list *call;
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call = zalloc(sizeof(*call));
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if (!call) {
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perror("not enough memory for the code path tree");
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return;
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}
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call->ip = chain->ips[i].ip;
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call->ms = chain->ips[i].ms;
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list_add_tail(&call->list, &node->val);
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}
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node->val_nr = chain->nr - start;
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if (!node->val_nr)
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pr_warning("Warning: empty node in callchain tree\n");
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}
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static void
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add_child(struct callchain_node *parent, struct resolved_chain *chain,
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int start, u64 period)
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{
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struct callchain_node *new;
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new = create_child(parent, false);
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fill_node(new, chain, start);
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new->children_hit = 0;
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new->hit = period;
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}
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/*
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* Split the parent in two parts (a new child is created) and
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* give a part of its callchain to the created child.
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* Then create another child to host the given callchain of new branch
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*/
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static void
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split_add_child(struct callchain_node *parent, struct resolved_chain *chain,
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struct callchain_list *to_split, int idx_parents, int idx_local,
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u64 period)
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{
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struct callchain_node *new;
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struct list_head *old_tail;
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unsigned int idx_total = idx_parents + idx_local;
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/* split */
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new = create_child(parent, true);
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/* split the callchain and move a part to the new child */
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old_tail = parent->val.prev;
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list_del_range(&to_split->list, old_tail);
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new->val.next = &to_split->list;
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new->val.prev = old_tail;
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to_split->list.prev = &new->val;
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old_tail->next = &new->val;
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/* split the hits */
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new->hit = parent->hit;
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new->children_hit = parent->children_hit;
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parent->children_hit = cumul_hits(new);
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new->val_nr = parent->val_nr - idx_local;
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parent->val_nr = idx_local;
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/* create a new child for the new branch if any */
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if (idx_total < chain->nr) {
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parent->hit = 0;
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add_child(parent, chain, idx_total, period);
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parent->children_hit += period;
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} else {
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parent->hit = period;
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}
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}
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static int
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append_chain(struct callchain_node *root, struct resolved_chain *chain,
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unsigned int start, u64 period);
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static void
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append_chain_children(struct callchain_node *root, struct resolved_chain *chain,
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unsigned int start, u64 period)
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{
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struct callchain_node *rnode;
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/* lookup in childrens */
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chain_for_each_child(rnode, root) {
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unsigned int ret = append_chain(rnode, chain, start, period);
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if (!ret)
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goto inc_children_hit;
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}
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/* nothing in children, add to the current node */
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add_child(root, chain, start, period);
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inc_children_hit:
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root->children_hit += period;
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}
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static int
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append_chain(struct callchain_node *root, struct resolved_chain *chain,
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unsigned int start, u64 period)
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{
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struct callchain_list *cnode;
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unsigned int i = start;
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bool found = false;
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/*
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* Lookup in the current node
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* If we have a symbol, then compare the start to match
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* anywhere inside a function.
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*/
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list_for_each_entry(cnode, &root->val, list) {
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struct symbol *sym;
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if (i == chain->nr)
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break;
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sym = chain->ips[i].ms.sym;
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if (cnode->ms.sym && sym) {
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if (cnode->ms.sym->start != sym->start)
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break;
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} else if (cnode->ip != chain->ips[i].ip)
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break;
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if (!found)
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found = true;
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i++;
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}
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/* matches not, relay on the parent */
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if (!found)
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return -1;
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/* we match only a part of the node. Split it and add the new chain */
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if (i - start < root->val_nr) {
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split_add_child(root, chain, cnode, start, i - start, period);
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return 0;
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}
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/* we match 100% of the path, increment the hit */
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if (i - start == root->val_nr && i == chain->nr) {
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root->hit += period;
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return 0;
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}
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/* We match the node and still have a part remaining */
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append_chain_children(root, chain, i, period);
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return 0;
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}
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static void filter_context(struct ip_callchain *old, struct resolved_chain *new,
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struct map_symbol *syms)
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{
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int i, j = 0;
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for (i = 0; i < (int)old->nr; i++) {
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if (old->ips[i] >= PERF_CONTEXT_MAX)
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continue;
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new->ips[j].ip = old->ips[i];
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new->ips[j].ms = syms[i];
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j++;
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}
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new->nr = j;
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}
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int callchain_append(struct callchain_root *root, struct ip_callchain *chain,
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struct map_symbol *syms, u64 period)
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{
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struct resolved_chain *filtered;
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if (!chain->nr)
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return 0;
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filtered = zalloc(sizeof(*filtered) +
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chain->nr * sizeof(struct resolved_ip));
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if (!filtered)
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return -ENOMEM;
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filter_context(chain, filtered, syms);
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if (!filtered->nr)
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goto end;
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append_chain_children(&root->node, filtered, 0, period);
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if (filtered->nr > root->max_depth)
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root->max_depth = filtered->nr;
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end:
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free(filtered);
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return 0;
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}
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static int
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merge_chain_branch(struct callchain_node *dst, struct callchain_node *src,
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struct resolved_chain *chain)
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{
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struct callchain_node *child, *next_child;
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struct callchain_list *list, *next_list;
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int old_pos = chain->nr;
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int err = 0;
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list_for_each_entry_safe(list, next_list, &src->val, list) {
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chain->ips[chain->nr].ip = list->ip;
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chain->ips[chain->nr].ms = list->ms;
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chain->nr++;
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list_del(&list->list);
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free(list);
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}
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if (src->hit)
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append_chain_children(dst, chain, 0, src->hit);
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chain_for_each_child_safe(child, next_child, src) {
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err = merge_chain_branch(dst, child, chain);
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if (err)
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break;
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list_del(&child->brothers);
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free(child);
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}
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chain->nr = old_pos;
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return err;
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}
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int callchain_merge(struct callchain_root *dst, struct callchain_root *src)
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{
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struct resolved_chain *chain;
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int err;
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chain = malloc(sizeof(*chain) +
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src->max_depth * sizeof(struct resolved_ip));
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if (!chain)
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return -ENOMEM;
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chain->nr = 0;
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err = merge_chain_branch(&dst->node, &src->node, chain);
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free(chain);
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return err;
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}
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