534 lines
12 KiB
C
534 lines
12 KiB
C
/*
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* Copyright (C) 2009-2011, 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 "hist.h"
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#include "util.h"
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#include "callchain.h"
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__thread struct callchain_cursor callchain_cursor;
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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 = callchain_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 = callchain_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 rb_node *n;
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struct callchain_node *child;
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n = rb_first(&node->rb_root_in);
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while (n) {
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child = rb_entry(n, struct callchain_node, rb_node_in);
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n = rb_next(n);
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__sort_chain_flat(rb_root, child, min_hit);
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}
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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 __maybe_unused)
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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 rb_node *n;
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struct callchain_node *child;
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node->rb_root = RB_ROOT;
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n = rb_first(&node->rb_root_in);
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while (n) {
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child = rb_entry(n, struct callchain_node, rb_node_in);
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n = rb_next(n);
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__sort_chain_graph_abs(child, min_hit);
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if (callchain_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 __maybe_unused)
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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 rb_node *n;
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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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n = rb_first(&node->rb_root_in);
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while (n) {
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child = rb_entry(n, struct callchain_node, rb_node_in);
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n = rb_next(n);
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__sort_chain_graph_rel(child, min_percent);
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if (callchain_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 __maybe_unused, 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 callchain_register_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->val);
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if (inherit_children) {
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struct rb_node *n;
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struct callchain_node *child;
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new->rb_root_in = parent->rb_root_in;
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parent->rb_root_in = RB_ROOT;
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n = rb_first(&new->rb_root_in);
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while (n) {
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child = rb_entry(n, struct callchain_node, rb_node_in);
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child->parent = new;
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n = rb_next(n);
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}
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/* make it the first child */
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rb_link_node(&new->rb_node_in, NULL, &parent->rb_root_in.rb_node);
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rb_insert_color(&new->rb_node_in, &parent->rb_root_in);
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}
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return new;
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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 callchain_cursor *cursor)
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{
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struct callchain_cursor_node *cursor_node;
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node->val_nr = cursor->nr - cursor->pos;
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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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cursor_node = callchain_cursor_current(cursor);
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while (cursor_node) {
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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 = cursor_node->ip;
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call->ms.sym = cursor_node->sym;
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call->ms.map = cursor_node->map;
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list_add_tail(&call->list, &node->val);
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callchain_cursor_advance(cursor);
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cursor_node = callchain_cursor_current(cursor);
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}
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}
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static struct callchain_node *
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add_child(struct callchain_node *parent,
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struct callchain_cursor *cursor,
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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, cursor);
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new->children_hit = 0;
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new->hit = period;
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return new;
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}
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static s64 match_chain(struct callchain_cursor_node *node,
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struct callchain_list *cnode)
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{
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struct symbol *sym = node->sym;
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if (cnode->ms.sym && sym &&
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callchain_param.key == CCKEY_FUNCTION)
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return cnode->ms.sym->start - sym->start;
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else
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return cnode->ip - node->ip;
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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,
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struct callchain_cursor *cursor,
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struct callchain_list *to_split,
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u64 idx_parents, u64 idx_local, 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 = callchain_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 < cursor->nr) {
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struct callchain_node *first;
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struct callchain_list *cnode;
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struct callchain_cursor_node *node;
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struct rb_node *p, **pp;
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parent->hit = 0;
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parent->children_hit += period;
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node = callchain_cursor_current(cursor);
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new = add_child(parent, cursor, period);
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/*
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* This is second child since we moved parent's children
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* to new (first) child above.
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*/
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p = parent->rb_root_in.rb_node;
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first = rb_entry(p, struct callchain_node, rb_node_in);
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cnode = list_first_entry(&first->val, struct callchain_list,
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list);
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if (match_chain(node, cnode) < 0)
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pp = &p->rb_left;
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else
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pp = &p->rb_right;
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rb_link_node(&new->rb_node_in, p, pp);
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rb_insert_color(&new->rb_node_in, &parent->rb_root_in);
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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,
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struct callchain_cursor *cursor,
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u64 period);
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static void
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append_chain_children(struct callchain_node *root,
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struct callchain_cursor *cursor,
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u64 period)
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{
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struct callchain_node *rnode;
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struct callchain_cursor_node *node;
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struct rb_node **p = &root->rb_root_in.rb_node;
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struct rb_node *parent = NULL;
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node = callchain_cursor_current(cursor);
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if (!node)
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return;
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/* lookup in childrens */
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while (*p) {
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s64 ret;
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struct callchain_list *cnode;
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parent = *p;
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rnode = rb_entry(parent, struct callchain_node, rb_node_in);
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cnode = list_first_entry(&rnode->val, struct callchain_list,
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list);
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/* just check first entry */
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ret = match_chain(node, cnode);
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if (ret == 0) {
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append_chain(rnode, cursor, period);
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goto inc_children_hit;
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}
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if (ret < 0)
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p = &parent->rb_left;
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else
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p = &parent->rb_right;
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}
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/* nothing in children, add to the current node */
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rnode = add_child(root, cursor, period);
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rb_link_node(&rnode->rb_node_in, parent, p);
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rb_insert_color(&rnode->rb_node_in, &root->rb_root_in);
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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,
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struct callchain_cursor *cursor,
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u64 period)
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{
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struct callchain_cursor_node *curr_snap = cursor->curr;
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struct callchain_list *cnode;
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u64 start = cursor->pos;
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bool found = false;
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u64 matches;
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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, unless function
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* mode is disabled.
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*/
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list_for_each_entry(cnode, &root->val, list) {
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struct callchain_cursor_node *node;
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node = callchain_cursor_current(cursor);
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if (!node)
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break;
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if (match_chain(node, cnode) != 0)
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break;
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found = true;
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callchain_cursor_advance(cursor);
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}
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/* matches not, relay no the parent */
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if (!found) {
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cursor->curr = curr_snap;
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cursor->pos = start;
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return -1;
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}
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matches = cursor->pos - start;
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/* we match only a part of the node. Split it and add the new chain */
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if (matches < root->val_nr) {
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split_add_child(root, cursor, cnode, start, matches, 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 (matches == root->val_nr && cursor->pos == cursor->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, cursor, period);
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return 0;
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}
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int callchain_append(struct callchain_root *root,
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struct callchain_cursor *cursor,
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u64 period)
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{
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if (!cursor->nr)
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return 0;
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callchain_cursor_commit(cursor);
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append_chain_children(&root->node, cursor, period);
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if (cursor->nr > root->max_depth)
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root->max_depth = cursor->nr;
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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_cursor *cursor,
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struct callchain_node *dst, struct callchain_node *src)
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{
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struct callchain_cursor_node **old_last = cursor->last;
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struct callchain_node *child;
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struct callchain_list *list, *next_list;
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struct rb_node *n;
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int old_pos = cursor->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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callchain_cursor_append(cursor, list->ip,
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list->ms.map, list->ms.sym);
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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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callchain_cursor_commit(cursor);
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append_chain_children(dst, cursor, src->hit);
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}
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n = rb_first(&src->rb_root_in);
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while (n) {
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child = container_of(n, struct callchain_node, rb_node_in);
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n = rb_next(n);
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rb_erase(&child->rb_node_in, &src->rb_root_in);
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err = merge_chain_branch(cursor, dst, child);
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if (err)
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break;
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free(child);
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}
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cursor->nr = old_pos;
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cursor->last = old_last;
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return err;
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}
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int callchain_merge(struct callchain_cursor *cursor,
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struct callchain_root *dst, struct callchain_root *src)
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{
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return merge_chain_branch(cursor, &dst->node, &src->node);
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}
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int callchain_cursor_append(struct callchain_cursor *cursor,
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u64 ip, struct map *map, struct symbol *sym)
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{
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struct callchain_cursor_node *node = *cursor->last;
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if (!node) {
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node = calloc(1, sizeof(*node));
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if (!node)
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return -ENOMEM;
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*cursor->last = node;
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}
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node->ip = ip;
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node->map = map;
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node->sym = sym;
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cursor->nr++;
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cursor->last = &node->next;
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return 0;
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}
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