callchain.c

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// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2009-2011, Frederic Weisbecker <fweisbec@gmail.com>
 *
 * Handle the callchains from the stream in an ad-hoc radix tree and then
 * sort them in an rbtree.
 *
 * Using a radix for code path provides a fast retrieval and factorizes
 * memory use. Also that lets us use the paths in a hierarchical graph view.
 *
 */

#include <inttypes.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdbool.h>
#include <errno.h>
#include <math.h>

#include "asm/bug.h"

#include "hist.h"
#include "util.h"
#include "sort.h"
#include "machine.h"
#include "callchain.h"
#include "branch.h"

#define CALLCHAIN_PARAM_DEFAULT         \
    .mode       = CHAIN_GRAPH_ABS,  \
    .min_percent    = 0.5,          \
    .order      = ORDER_CALLEE,     \
    .key        = CCKEY_FUNCTION,   \
    .value      = CCVAL_PERCENT,    \

struct callchain_param callchain_param = {
    CALLCHAIN_PARAM_DEFAULT
};

/*
 * Are there any events usind DWARF callchains?
 *
 * I.e.
 *
 * -e cycles/call-graph=dwarf/
 */
bool dwarf_callchain_users;

struct callchain_param callchain_param_default = {
    CALLCHAIN_PARAM_DEFAULT
};

__thread struct callchain_cursor callchain_cursor;

int parse_callchain_record_opt(const char *arg, struct callchain_param *param)
{
    return parse_callchain_record(arg, param);
}

static int parse_callchain_mode(const char *value)
{
    if (!strncmp(value, "graph", strlen(value))) {
        callchain_param.mode = CHAIN_GRAPH_ABS;
        return 0;
    }
    if (!strncmp(value, "flat", strlen(value))) {
        callchain_param.mode = CHAIN_FLAT;
        return 0;
    }
    if (!strncmp(value, "fractal", strlen(value))) {
        callchain_param.mode = CHAIN_GRAPH_REL;
        return 0;
    }
    if (!strncmp(value, "folded", strlen(value))) {
        callchain_param.mode = CHAIN_FOLDED;
        return 0;
    }
    return -1;
}

static int parse_callchain_order(const char *value)
{
    if (!strncmp(value, "caller", strlen(value))) {
        callchain_param.order = ORDER_CALLER;
        callchain_param.order_set = true;
        return 0;
    }
    if (!strncmp(value, "callee", strlen(value))) {
        callchain_param.order = ORDER_CALLEE;
        callchain_param.order_set = true;
        return 0;
    }
    return -1;
}

static int parse_callchain_sort_key(const char *value)
{
    if (!strncmp(value, "function", strlen(value))) {
        callchain_param.key = CCKEY_FUNCTION;
        return 0;
    }
    if (!strncmp(value, "address", strlen(value))) {
        callchain_param.key = CCKEY_ADDRESS;
        return 0;
    }
    if (!strncmp(value, "srcline", strlen(value))) {
        callchain_param.key = CCKEY_SRCLINE;
        return 0;
    }
    if (!strncmp(value, "branch", strlen(value))) {
        callchain_param.branch_callstack = 1;
        return 0;
    }
    return -1;
}

static int parse_callchain_value(const char *value)
{
    if (!strncmp(value, "percent", strlen(value))) {
        callchain_param.value = CCVAL_PERCENT;
        return 0;
    }
    if (!strncmp(value, "period", strlen(value))) {
        callchain_param.value = CCVAL_PERIOD;
        return 0;
    }
    if (!strncmp(value, "count", strlen(value))) {
        callchain_param.value = CCVAL_COUNT;
        return 0;
    }
    return -1;
}

static int get_stack_size(const char *str, unsigned long *_size)
{
    char *endptr;
    unsigned long size;
    unsigned long max_size = round_down(USHRT_MAX, sizeof(u64));

    size = strtoul(str, &endptr, 0);

    do {
        if (*endptr)
            break;

        size = round_up(size, sizeof(u64));
        if (!size || size > max_size)
            break;

        *_size = size;
        return 0;

    } while (0);

    pr_err("callchain: Incorrect stack dump size (max %ld): %s\n",
           max_size, str);
    return -1;
}

static int
__parse_callchain_report_opt(const char *arg, bool allow_record_opt)
{
    char *tok;
    char *endptr, *saveptr = NULL;
    bool minpcnt_set = false;
    bool record_opt_set = false;
    bool try_stack_size = false;

    callchain_param.enabled = true;
    symbol_conf.use_callchain = true;

    if (!arg)
        return 0;

    while ((tok = strtok_r((char *)arg, ",", &saveptr)) != NULL) {
        if (!strncmp(tok, "none", strlen(tok))) {
            callchain_param.mode = CHAIN_NONE;
            callchain_param.enabled = false;
            symbol_conf.use_callchain = false;
            return 0;
        }

        if (!parse_callchain_mode(tok) ||
            !parse_callchain_order(tok) ||
            !parse_callchain_sort_key(tok) ||
            !parse_callchain_value(tok)) {
            /* parsing ok - move on to the next */
            try_stack_size = false;
            goto next;
        } else if (allow_record_opt && !record_opt_set) {
            if (parse_callchain_record(tok, &callchain_param))
                goto try_numbers;

            /* assume that number followed by 'dwarf' is stack size */
            if (callchain_param.record_mode == CALLCHAIN_DWARF)
                try_stack_size = true;

            record_opt_set = true;
            goto next;
        }

try_numbers:
        if (try_stack_size) {
            unsigned long size = 0;

            if (get_stack_size(tok, &size) < 0)
                return -1;
            callchain_param.dump_size = size;
            try_stack_size = false;
        } else if (!minpcnt_set) {
            /* try to get the min percent */
            callchain_param.min_percent = strtod(tok, &endptr);
            if (tok == endptr)
                return -1;
            minpcnt_set = true;
        } else {
            /* try print limit at last */
            callchain_param.print_limit = strtoul(tok, &endptr, 0);
            if (tok == endptr)
                return -1;
        }
next:
        arg = NULL;
    }

    if (callchain_register_param(&callchain_param) < 0) {
        pr_err("Can't register callchain params\n");
        return -1;
    }
    return 0;
}

int parse_callchain_report_opt(const char *arg)
{
    return __parse_callchain_report_opt(arg, false);
}

int parse_callchain_top_opt(const char *arg)
{
    return __parse_callchain_report_opt(arg, true);
}

int parse_callchain_record(const char *arg, struct callchain_param *param)
{
    char *tok, *name, *saveptr = NULL;
    char *buf;
    int ret = -1;

    /* We need buffer that we know we can write to. */
    buf = malloc(strlen(arg) + 1);
    if (!buf)
        return -ENOMEM;

    strcpy(buf, arg);

    tok = strtok_r((char *)buf, ",", &saveptr);
    name = tok ? : (char *)buf;

    do {
        /* Framepointer style */
        if (!strncmp(name, "fp", sizeof("fp"))) {
            if (!strtok_r(NULL, ",", &saveptr)) {
                param->record_mode = CALLCHAIN_FP;
                ret = 0;
            } else
                pr_err("callchain: No more arguments "
                       "needed for --call-graph fp\n");
            break;

        /* Dwarf style */
        } else if (!strncmp(name, "dwarf", sizeof("dwarf"))) {
            const unsigned long default_stack_dump_size = 8192;

            ret = 0;
            param->record_mode = CALLCHAIN_DWARF;
            param->dump_size = default_stack_dump_size;
            dwarf_callchain_users = true;

            tok = strtok_r(NULL, ",", &saveptr);
            if (tok) {
                unsigned long size = 0;

                ret = get_stack_size(tok, &size);
                param->dump_size = size;
            }
        } else if (!strncmp(name, "lbr", sizeof("lbr"))) {
            if (!strtok_r(NULL, ",", &saveptr)) {
                param->record_mode = CALLCHAIN_LBR;
                ret = 0;
            } else
                pr_err("callchain: No more arguments "
                    "needed for --call-graph lbr\n");
            break;
        } else {
            pr_err("callchain: Unknown --call-graph option "
                   "value: %s\n", arg);
            break;
        }

    } while (0);

    free(buf);
    return ret;
}

int perf_callchain_config(const char *var, const char *value)
{
    char *endptr;

    if (!strstarts(var, "call-graph."))
        return 0;
    var += sizeof("call-graph.") - 1;

    if (!strcmp(var, "record-mode"))
        return parse_callchain_record_opt(value, &callchain_param);
    if (!strcmp(var, "dump-size")) {
        unsigned long size = 0;
        int ret;

        ret = get_stack_size(value, &size);
        callchain_param.dump_size = size;

        return ret;
    }
    if (!strcmp(var, "print-type")){
        int ret;
        ret = parse_callchain_mode(value);
        if (ret == -1)
            pr_err("Invalid callchain mode: %s\n", value);
        return ret;
    }
    if (!strcmp(var, "order")){
        int ret;
        ret = parse_callchain_order(value);
        if (ret == -1)
            pr_err("Invalid callchain order: %s\n", value);
        return ret;
    }
    if (!strcmp(var, "sort-key")){
        int ret;
        ret = parse_callchain_sort_key(value);
        if (ret == -1)
            pr_err("Invalid callchain sort key: %s\n", value);
        return ret;
    }
    if (!strcmp(var, "threshold")) {
        callchain_param.min_percent = strtod(value, &endptr);
        if (value == endptr) {
            pr_err("Invalid callchain threshold: %s\n", value);
            return -1;
        }
    }
    if (!strcmp(var, "print-limit")) {
        callchain_param.print_limit = strtod(value, &endptr);
        if (value == endptr) {
            pr_err("Invalid callchain print limit: %s\n", value);
            return -1;
        }
    }

    return 0;
}

static void
rb_insert_callchain(struct rb_root *root, struct callchain_node *chain,
            enum chain_mode mode)
{
    struct rb_node **p = &root->rb_node;
    struct rb_node *parent = NULL;
    struct callchain_node *rnode;
    u64 chain_cumul = callchain_cumul_hits(chain);

    while (*p) {
        u64 rnode_cumul;

        parent = *p;
        rnode = rb_entry(parent, struct callchain_node, rb_node);
        rnode_cumul = callchain_cumul_hits(rnode);

        switch (mode) {
        case CHAIN_FLAT:
        case CHAIN_FOLDED:
            if (rnode->hit < chain->hit)
                p = &(*p)->rb_left;
            else
                p = &(*p)->rb_right;
            break;
        case CHAIN_GRAPH_ABS: /* Falldown */
        case CHAIN_GRAPH_REL:
            if (rnode_cumul < chain_cumul)
                p = &(*p)->rb_left;
            else
                p = &(*p)->rb_right;
            break;
        case CHAIN_NONE:
        default:
            break;
        }
    }

    rb_link_node(&chain->rb_node, parent, p);
    rb_insert_color(&chain->rb_node, root);
}

static void
__sort_chain_flat(struct rb_root *rb_root, struct callchain_node *node,
          u64 min_hit)
{
    struct rb_node *n;
    struct callchain_node *child;

    n = rb_first(&node->rb_root_in);
    while (n) {
        child = rb_entry(n, struct callchain_node, rb_node_in);
        n = rb_next(n);

        __sort_chain_flat(rb_root, child, min_hit);
    }

    if (node->hit && node->hit >= min_hit)
        rb_insert_callchain(rb_root, node, CHAIN_FLAT);
}

/*
 * Once we get every callchains from the stream, we can now
 * sort them by hit
 */
static void
sort_chain_flat(struct rb_root *rb_root, struct callchain_root *root,
        u64 min_hit, struct callchain_param *param __maybe_unused)
{
    *rb_root = RB_ROOT;
    __sort_chain_flat(rb_root, &root->node, min_hit);
}

static void __sort_chain_graph_abs(struct callchain_node *node,
                   u64 min_hit)
{
    struct rb_node *n;
    struct callchain_node *child;

    node->rb_root = RB_ROOT;
    n = rb_first(&node->rb_root_in);

    while (n) {
        child = rb_entry(n, struct callchain_node, rb_node_in);
        n = rb_next(n);

        __sort_chain_graph_abs(child, min_hit);
        if (callchain_cumul_hits(child) >= min_hit)
            rb_insert_callchain(&node->rb_root, child,
                        CHAIN_GRAPH_ABS);
    }
}

static void
sort_chain_graph_abs(struct rb_root *rb_root, struct callchain_root *chain_root,
             u64 min_hit, struct callchain_param *param __maybe_unused)
{
    __sort_chain_graph_abs(&chain_root->node, min_hit);
    rb_root->rb_node = chain_root->node.rb_root.rb_node;
}

static void __sort_chain_graph_rel(struct callchain_node *node,
                   double min_percent)
{
    struct rb_node *n;
    struct callchain_node *child;
    u64 min_hit;

    node->rb_root = RB_ROOT;
    min_hit = ceil(node->children_hit * min_percent);

    n = rb_first(&node->rb_root_in);
    while (n) {
        child = rb_entry(n, struct callchain_node, rb_node_in);
        n = rb_next(n);

        __sort_chain_graph_rel(child, min_percent);
        if (callchain_cumul_hits(child) >= min_hit)
            rb_insert_callchain(&node->rb_root, child,
                        CHAIN_GRAPH_REL);
    }
}

static void
sort_chain_graph_rel(struct rb_root *rb_root, struct callchain_root *chain_root,
             u64 min_hit __maybe_unused, struct callchain_param *param)
{
    __sort_chain_graph_rel(&chain_root->node, param->min_percent / 100.0);
    rb_root->rb_node = chain_root->node.rb_root.rb_node;
}

int callchain_register_param(struct callchain_param *param)
{
    switch (param->mode) {
    case CHAIN_GRAPH_ABS:
        param->sort = sort_chain_graph_abs;
        break;
    case CHAIN_GRAPH_REL:
        param->sort = sort_chain_graph_rel;
        break;
    case CHAIN_FLAT:
    case CHAIN_FOLDED:
        param->sort = sort_chain_flat;
        break;
    case CHAIN_NONE:
    default:
        return -1;
    }
    return 0;
}

/*
 * Create a child for a parent. If inherit_children, then the new child
 * will become the new parent of it's parent children
 */
static struct callchain_node *
create_child(struct callchain_node *parent, bool inherit_children)
{
    struct callchain_node *new;

    new = zalloc(sizeof(*new));
    if (!new) {
        perror("not enough memory to create child for code path tree");
        return NULL;
    }
    new->parent = parent;
    INIT_LIST_HEAD(&new->val);
    INIT_LIST_HEAD(&new->parent_val);

    if (inherit_children) {
        struct rb_node *n;
        struct callchain_node *child;

        new->rb_root_in = parent->rb_root_in;
        parent->rb_root_in = RB_ROOT;

        n = rb_first(&new->rb_root_in);
        while (n) {
            child = rb_entry(n, struct callchain_node, rb_node_in);
            child->parent = new;
            n = rb_next(n);
        }

        /* make it the first child */
        rb_link_node(&new->rb_node_in, NULL, &parent->rb_root_in.rb_node);
        rb_insert_color(&new->rb_node_in, &parent->rb_root_in);
    }

    return new;
}


/*
 * Fill the node with callchain values
 */
static int
fill_node(struct callchain_node *node, struct callchain_cursor *cursor)
{
    struct callchain_cursor_node *cursor_node;

    node->val_nr = cursor->nr - cursor->pos;
    if (!node->val_nr)
        pr_warning("Warning: empty node in callchain tree\n");

    cursor_node = callchain_cursor_current(cursor);

    while (cursor_node) {
        struct callchain_list *call;

        call = zalloc(sizeof(*call));
        if (!call) {
            perror("not enough memory for the code path tree");
            return -1;
        }
        call->ip = cursor_node->ip;
        call->ms.sym = cursor_node->sym;
        call->ms.map = map__get(cursor_node->map);
        call->srcline = cursor_node->srcline;

        if (cursor_node->branch) {
            call->branch_count = 1;

            if (cursor_node->branch_from) {
                /*
                 * branch_from is set with value somewhere else
                 * to imply it's "to" of a branch.
                 */
                call->brtype_stat.branch_to = true;

                if (cursor_node->branch_flags.predicted)
                    call->predicted_count = 1;

                if (cursor_node->branch_flags.abort)
                    call->abort_count = 1;

                branch_type_count(&call->brtype_stat,
                          &cursor_node->branch_flags,
                          cursor_node->branch_from,
                          cursor_node->ip);
            } else {
                /*
                 * It's "from" of a branch
                 */
                call->brtype_stat.branch_to = false;
                call->cycles_count =
                    cursor_node->branch_flags.cycles;
                call->iter_count = cursor_node->nr_loop_iter;
                call->iter_cycles = cursor_node->iter_cycles;
            }
        }

        list_add_tail(&call->list, &node->val);

        callchain_cursor_advance(cursor);
        cursor_node = callchain_cursor_current(cursor);
    }
    return 0;
}

static struct callchain_node *
add_child(struct callchain_node *parent,
      struct callchain_cursor *cursor,
      u64 period)
{
    struct callchain_node *new;

    new = create_child(parent, false);
    if (new == NULL)
        return NULL;

    if (fill_node(new, cursor) < 0) {
        struct callchain_list *call, *tmp;

        list_for_each_entry_safe(call, tmp, &new->val, list) {
            list_del(&call->list);
            map__zput(call->ms.map);
            free(call);
        }
        free(new);
        return NULL;
    }

    new->children_hit = 0;
    new->hit = period;
    new->children_count = 0;
    new->count = 1;
    return new;
}

enum match_result {
    MATCH_ERROR  = -1,
    MATCH_EQ,
    MATCH_LT,
    MATCH_GT,
};

static enum match_result match_chain_strings(const char *left,
                         const char *right)
{
    enum match_result ret = MATCH_EQ;
    int cmp;

    if (left && right)
        cmp = strcmp(left, right);
    else if (!left && right)
        cmp = 1;
    else if (left && !right)
        cmp = -1;
    else
        return MATCH_ERROR;

    if (cmp != 0)
        ret = cmp < 0 ? MATCH_LT : MATCH_GT;

    return ret;
}

/*
 * We need to always use relative addresses because we're aggregating
 * callchains from multiple threads, i.e. different address spaces, so
 * comparing absolute addresses make no sense as a symbol in a DSO may end up
 * in a different address when used in a different binary or even the same
 * binary but with some sort of address randomization technique, thus we need
 * to compare just relative addresses. -acme
 */
static enum match_result match_chain_dso_addresses(struct map *left_map, u64 left_ip,
                           struct map *right_map, u64 right_ip)
{
    struct dso *left_dso = left_map ? left_map->dso : NULL;
    struct dso *right_dso = right_map ? right_map->dso : NULL;

    if (left_dso != right_dso)
        return left_dso < right_dso ? MATCH_LT : MATCH_GT;

    if (left_ip != right_ip)
        return left_ip < right_ip ? MATCH_LT : MATCH_GT;

    return MATCH_EQ;
}

static enum match_result match_chain(struct callchain_cursor_node *node,
                     struct callchain_list *cnode)
{
    enum match_result match = MATCH_ERROR;

    switch (callchain_param.key) {
    case CCKEY_SRCLINE:
        match = match_chain_strings(cnode->srcline, node->srcline);
        if (match != MATCH_ERROR)
            break;
        /* otherwise fall-back to symbol-based comparison below */
        __fallthrough;
    case CCKEY_FUNCTION:
        if (node->sym && cnode->ms.sym) {
            /*
             * Compare inlined frames based on their symbol name
             * because different inlined frames will have the same
             * symbol start. Otherwise do a faster comparison based
             * on the symbol start address.
             */
            if (cnode->ms.sym->inlined || node->sym->inlined) {
                match = match_chain_strings(cnode->ms.sym->name,
                                node->sym->name);
                if (match != MATCH_ERROR)
                    break;
            } else {
                match = match_chain_dso_addresses(cnode->ms.map, cnode->ms.sym->start,
                                  node->map, node->sym->start);
                break;
            }
        }
        /* otherwise fall-back to IP-based comparison below */
        __fallthrough;
    case CCKEY_ADDRESS:
    default:
        match = match_chain_dso_addresses(cnode->ms.map, cnode->ip, node->map, node->ip);
        break;
    }

    if (match == MATCH_EQ && node->branch) {
        cnode->branch_count++;

        if (node->branch_from) {
            /*
             * It's "to" of a branch
             */
            cnode->brtype_stat.branch_to = true;

            if (node->branch_flags.predicted)
                cnode->predicted_count++;

            if (node->branch_flags.abort)
                cnode->abort_count++;

            branch_type_count(&cnode->brtype_stat,
                      &node->branch_flags,
                      node->branch_from,
                      node->ip);
        } else {
            /*
             * It's "from" of a branch
             */
            cnode->brtype_stat.branch_to = false;
            cnode->cycles_count += node->branch_flags.cycles;
            cnode->iter_count += node->nr_loop_iter;
            cnode->iter_cycles += node->iter_cycles;
        }
    }

    return match;
}

/*
 * Split the parent in two parts (a new child is created) and
 * give a part of its callchain to the created child.
 * Then create another child to host the given callchain of new branch
 */
static int
split_add_child(struct callchain_node *parent,
        struct callchain_cursor *cursor,
        struct callchain_list *to_split,
        u64 idx_parents, u64 idx_local, u64 period)
{
    struct callchain_node *new;
    struct list_head *old_tail;
    unsigned int idx_total = idx_parents + idx_local;

    /* split */
    new = create_child(parent, true);
    if (new == NULL)
        return -1;

    /* split the callchain and move a part to the new child */
    old_tail = parent->val.prev;
    list_del_range(&to_split->list, old_tail);
    new->val.next = &to_split->list;
    new->val.prev = old_tail;
    to_split->list.prev = &new->val;
    old_tail->next = &new->val;

    /* split the hits */
    new->hit = parent->hit;
    new->children_hit = parent->children_hit;
    parent->children_hit = callchain_cumul_hits(new);
    new->val_nr = parent->val_nr - idx_local;
    parent->val_nr = idx_local;
    new->count = parent->count;
    new->children_count = parent->children_count;
    parent->children_count = callchain_cumul_counts(new);

    /* create a new child for the new branch if any */
    if (idx_total < cursor->nr) {
        struct callchain_node *first;
        struct callchain_list *cnode;
        struct callchain_cursor_node *node;
        struct rb_node *p, **pp;

        parent->hit = 0;
        parent->children_hit += period;
        parent->count = 0;
        parent->children_count += 1;

        node = callchain_cursor_current(cursor);
        new = add_child(parent, cursor, period);
        if (new == NULL)
            return -1;

        /*
         * This is second child since we moved parent's children
         * to new (first) child above.
         */
        p = parent->rb_root_in.rb_node;
        first = rb_entry(p, struct callchain_node, rb_node_in);
        cnode = list_first_entry(&first->val, struct callchain_list,
                     list);

        if (match_chain(node, cnode) == MATCH_LT)
            pp = &p->rb_left;
        else
            pp = &p->rb_right;

        rb_link_node(&new->rb_node_in, p, pp);
        rb_insert_color(&new->rb_node_in, &parent->rb_root_in);
    } else {
        parent->hit = period;
        parent->count = 1;
    }
    return 0;
}

static enum match_result
append_chain(struct callchain_node *root,
         struct callchain_cursor *cursor,
         u64 period);

static int
append_chain_children(struct callchain_node *root,
              struct callchain_cursor *cursor,
              u64 period)
{
    struct callchain_node *rnode;
    struct callchain_cursor_node *node;
    struct rb_node **p = &root->rb_root_in.rb_node;
    struct rb_node *parent = NULL;

    node = callchain_cursor_current(cursor);
    if (!node)
        return -1;

    /* lookup in childrens */
    while (*p) {
        enum match_result ret;

        parent = *p;
        rnode = rb_entry(parent, struct callchain_node, rb_node_in);

        /* If at least first entry matches, rely to children */
        ret = append_chain(rnode, cursor, period);
        if (ret == MATCH_EQ)
            goto inc_children_hit;
        if (ret == MATCH_ERROR)
            return -1;

        if (ret == MATCH_LT)
            p = &parent->rb_left;
        else
            p = &parent->rb_right;
    }
    /* nothing in children, add to the current node */
    rnode = add_child(root, cursor, period);
    if (rnode == NULL)
        return -1;

    rb_link_node(&rnode->rb_node_in, parent, p);
    rb_insert_color(&rnode->rb_node_in, &root->rb_root_in);

inc_children_hit:
    root->children_hit += period;
    root->children_count++;
    return 0;
}

static enum match_result
append_chain(struct callchain_node *root,
         struct callchain_cursor *cursor,
         u64 period)
{
    struct callchain_list *cnode;
    u64 start = cursor->pos;
    bool found = false;
    u64 matches;
    enum match_result cmp = MATCH_ERROR;

    /*
     * Lookup in the current node
     * If we have a symbol, then compare the start to match
     * anywhere inside a function, unless function
     * mode is disabled.
     */
    list_for_each_entry(cnode, &root->val, list) {
        struct callchain_cursor_node *node;

        node = callchain_cursor_current(cursor);
        if (!node)
            break;

        cmp = match_chain(node, cnode);
        if (cmp != MATCH_EQ)
            break;

        found = true;

        callchain_cursor_advance(cursor);
    }

    /* matches not, relay no the parent */
    if (!found) {
        WARN_ONCE(cmp == MATCH_ERROR, "Chain comparison error\n");
        return cmp;
    }

    matches = cursor->pos - start;

    /* we match only a part of the node. Split it and add the new chain */
    if (matches < root->val_nr) {
        if (split_add_child(root, cursor, cnode, start, matches,
                    period) < 0)
            return MATCH_ERROR;

        return MATCH_EQ;
    }

    /* we match 100% of the path, increment the hit */
    if (matches == root->val_nr && cursor->pos == cursor->nr) {
        root->hit += period;
        root->count++;
        return MATCH_EQ;
    }

    /* We match the node and still have a part remaining */
    if (append_chain_children(root, cursor, period) < 0)
        return MATCH_ERROR;

    return MATCH_EQ;
}

int callchain_append(struct callchain_root *root,
             struct callchain_cursor *cursor,
             u64 period)
{
    if (!cursor->nr)
        return 0;

    callchain_cursor_commit(cursor);

    if (append_chain_children(&root->node, cursor, period) < 0)
        return -1;

    if (cursor->nr > root->max_depth)
        root->max_depth = cursor->nr;

    return 0;
}

static int
merge_chain_branch(struct callchain_cursor *cursor,
           struct callchain_node *dst, struct callchain_node *src)
{
    struct callchain_cursor_node **old_last = cursor->last;
    struct callchain_node *child;
    struct callchain_list *list, *next_list;
    struct rb_node *n;
    int old_pos = cursor->nr;
    int err = 0;

    list_for_each_entry_safe(list, next_list, &src->val, list) {
        callchain_cursor_append(cursor, list->ip,
                    list->ms.map, list->ms.sym,
                    false, NULL, 0, 0, 0, list->srcline);
        list_del(&list->list);
        map__zput(list->ms.map);
        free(list);
    }

    if (src->hit) {
        callchain_cursor_commit(cursor);
        if (append_chain_children(dst, cursor, src->hit) < 0)
            return -1;
    }

    n = rb_first(&src->rb_root_in);
    while (n) {
        child = container_of(n, struct callchain_node, rb_node_in);
        n = rb_next(n);
        rb_erase(&child->rb_node_in, &src->rb_root_in);

        err = merge_chain_branch(cursor, dst, child);
        if (err)
            break;

        free(child);
    }

    cursor->nr = old_pos;
    cursor->last = old_last;

    return err;
}

int callchain_merge(struct callchain_cursor *cursor,
            struct callchain_root *dst, struct callchain_root *src)
{
    return merge_chain_branch(cursor, &dst->node, &src->node);
}

int callchain_cursor_append(struct callchain_cursor *cursor,
                u64 ip, struct map *map, struct symbol *sym,
                bool branch, struct branch_flags *flags,
                int nr_loop_iter, u64 iter_cycles, u64 branch_from,
                const char *srcline)
{
    struct callchain_cursor_node *node = *cursor->last;

    if (!node) {
        node = calloc(1, sizeof(*node));
        if (!node)
            return -ENOMEM;

        *cursor->last = node;
    }

    node->ip = ip;
    map__zput(node->map);
    node->map = map__get(map);
    node->sym = sym;
    node->branch = branch;
    node->nr_loop_iter = nr_loop_iter;
    node->iter_cycles = iter_cycles;
    node->srcline = srcline;

    if (flags)
        memcpy(&node->branch_flags, flags,
            sizeof(struct branch_flags));

    node->branch_from = branch_from;
    cursor->nr++;

    cursor->last = &node->next;

    return 0;
}

int sample__resolve_callchain(struct perf_sample *sample,
                  struct callchain_cursor *cursor, struct symbol **parent,
                  struct perf_evsel *evsel, struct addr_location *al,
                  int max_stack)
{
    if (sample->callchain == NULL && !symbol_conf.show_branchflag_count)
        return 0;

    if (symbol_conf.use_callchain || symbol_conf.cumulate_callchain ||
        perf_hpp_list.parent || symbol_conf.show_branchflag_count) {
        return thread__resolve_callchain(al->thread, cursor, evsel, sample,
                         parent, al, max_stack);
    }
    return 0;
}

int hist_entry__append_callchain(struct hist_entry *he, struct perf_sample *sample)
{
    if ((!symbol_conf.use_callchain || sample->callchain == NULL) &&
        !symbol_conf.show_branchflag_count)
        return 0;
    return callchain_append(he->callchain, &callchain_cursor, sample->period);
}

int fill_callchain_info(struct addr_location *al, struct callchain_cursor_node *node,
            bool hide_unresolved)
{
    al->map = node->map;
    al->sym = node->sym;
    al->srcline = node->srcline;
    al->addr = node->ip;

    if (al->sym == NULL) {
        if (hide_unresolved)
            return 0;
        if (al->map == NULL)
            goto out;
    }

    if (al->map->groups == &al->machine->kmaps) {
        if (machine__is_host(al->machine)) {
            al->cpumode = PERF_RECORD_MISC_KERNEL;
            al->level = 'k';
        } else {
            al->cpumode = PERF_RECORD_MISC_GUEST_KERNEL;
            al->level = 'g';
        }
    } else {
        if (machine__is_host(al->machine)) {
            al->cpumode = PERF_RECORD_MISC_USER;
            al->level = '.';
        } else if (perf_guest) {
            al->cpumode = PERF_RECORD_MISC_GUEST_USER;
            al->level = 'u';
        } else {
            al->cpumode = PERF_RECORD_MISC_HYPERVISOR;
            al->level = 'H';
        }
    }

out:
    return 1;
}

char *callchain_list__sym_name(struct callchain_list *cl,
                   char *bf, size_t bfsize, bool show_dso)
{
    bool show_addr = callchain_param.key == CCKEY_ADDRESS;
    bool show_srcline = show_addr || callchain_param.key == CCKEY_SRCLINE;
    int printed;

    if (cl->ms.sym) {
        const char *inlined = cl->ms.sym->inlined ? " (inlined)" : "";

        if (show_srcline && cl->srcline)
            printed = scnprintf(bf, bfsize, "%s %s%s",
                        cl->ms.sym->name, cl->srcline,
                        inlined);
        else
            printed = scnprintf(bf, bfsize, "%s%s",
                        cl->ms.sym->name, inlined);
    } else
        printed = scnprintf(bf, bfsize, "%#" PRIx64, cl->ip);

    if (show_dso)
        scnprintf(bf + printed, bfsize - printed, " %s",
              cl->ms.map ?
              cl->ms.map->dso->short_name :
              "unknown");

    return bf;
}

char *callchain_node__scnprintf_value(struct callchain_node *node,
                      char *bf, size_t bfsize, u64 total)
{
    double percent = 0.0;
    u64 period = callchain_cumul_hits(node);
    unsigned count = callchain_cumul_counts(node);

    if (callchain_param.mode == CHAIN_FOLDED) {
        period = node->hit;
        count = node->count;
    }

    switch (callchain_param.value) {
    case CCVAL_PERIOD:
        scnprintf(bf, bfsize, "%"PRIu64, period);
        break;
    case CCVAL_COUNT:
        scnprintf(bf, bfsize, "%u", count);
        break;
    case CCVAL_PERCENT:
    default:
        if (total)
            percent = period * 100.0 / total;
        scnprintf(bf, bfsize, "%.2f%%", percent);
        break;
    }
    return bf;
}

int callchain_node__fprintf_value(struct callchain_node *node,
                 FILE *fp, u64 total)
{
    double percent = 0.0;
    u64 period = callchain_cumul_hits(node);
    unsigned count = callchain_cumul_counts(node);

    if (callchain_param.mode == CHAIN_FOLDED) {
        period = node->hit;
        count = node->count;
    }

    switch (callchain_param.value) {
    case CCVAL_PERIOD:
        return fprintf(fp, "%"PRIu64, period);
    case CCVAL_COUNT:
        return fprintf(fp, "%u", count);
    case CCVAL_PERCENT:
    default:
        if (total)
            percent = period * 100.0 / total;
        return percent_color_fprintf(fp, "%.2f%%", percent);
    }
    return 0;
}

static void callchain_counts_value(struct callchain_node *node,
                   u64 *branch_count, u64 *predicted_count,
                   u64 *abort_count, u64 *cycles_count)
{
    struct callchain_list *clist;

    list_for_each_entry(clist, &node->val, list) {
        if (branch_count)
            *branch_count += clist->branch_count;

        if (predicted_count)
            *predicted_count += clist->predicted_count;

        if (abort_count)
            *abort_count += clist->abort_count;

        if (cycles_count)
            *cycles_count += clist->cycles_count;
    }
}

static int callchain_node_branch_counts_cumul(struct callchain_node *node,
                          u64 *branch_count,
                          u64 *predicted_count,
                          u64 *abort_count,
                          u64 *cycles_count)
{
    struct callchain_node *child;
    struct rb_node *n;

    n = rb_first(&node->rb_root_in);
    while (n) {
        child = rb_entry(n, struct callchain_node, rb_node_in);
        n = rb_next(n);

        callchain_node_branch_counts_cumul(child, branch_count,
                           predicted_count,
                           abort_count,
                           cycles_count);

        callchain_counts_value(child, branch_count,
                       predicted_count, abort_count,
                       cycles_count);
    }

    return 0;
}

int callchain_branch_counts(struct callchain_root *root,
                u64 *branch_count, u64 *predicted_count,
                u64 *abort_count, u64 *cycles_count)
{
    if (branch_count)
        *branch_count = 0;

    if (predicted_count)
        *predicted_count = 0;

    if (abort_count)
        *abort_count = 0;

    if (cycles_count)
        *cycles_count = 0;

    return callchain_node_branch_counts_cumul(&root->node,
                          branch_count,
                          predicted_count,
                          abort_count,
                          cycles_count);
}

static int count_pri64_printf(int idx, const char *str, u64 value, char *bf, int bfsize)
{
    int printed;

    printed = scnprintf(bf, bfsize, "%s%s:%" PRId64 "", (idx) ? " " : " (", str, value);

    return printed;
}

static int count_float_printf(int idx, const char *str, float value,
                  char *bf, int bfsize, float threshold)
{
    int printed;

    if (threshold != 0.0 && value < threshold)
        return 0;

    printed = scnprintf(bf, bfsize, "%s%s:%.1f%%", (idx) ? " " : " (", str, value);

    return printed;
}

static int branch_to_str(char *bf, int bfsize,
             u64 branch_count, u64 predicted_count,
             u64 abort_count,
             struct branch_type_stat *brtype_stat)
{
    int printed, i = 0;

    printed = branch_type_str(brtype_stat, bf, bfsize);
    if (printed)
        i++;

    if (predicted_count < branch_count) {
        printed += count_float_printf(i++, "predicted",
                predicted_count * 100.0 / branch_count,
                bf + printed, bfsize - printed, 0.0);
    }

    if (abort_count) {
        printed += count_float_printf(i++, "abort",
                abort_count * 100.0 / branch_count,
                bf + printed, bfsize - printed, 0.1);
    }

    if (i)
        printed += scnprintf(bf + printed, bfsize - printed, ")");

    return printed;
}

static int branch_from_str(char *bf, int bfsize,
               u64 branch_count,
               u64 cycles_count, u64 iter_count,
               u64 iter_cycles)
{
    int printed = 0, i = 0;
    u64 cycles;

    cycles = cycles_count / branch_count;
    if (cycles) {
        printed += count_pri64_printf(i++, "cycles",
                cycles,
                bf + printed, bfsize - printed);
    }

    if (iter_count) {
        printed += count_pri64_printf(i++, "iter",
                iter_count,
                bf + printed, bfsize - printed);

        printed += count_pri64_printf(i++, "avg_cycles",
                iter_cycles / iter_count,
                bf + printed, bfsize - printed);
    }

    if (i)
        printed += scnprintf(bf + printed, bfsize - printed, ")");

    return printed;
}

static int counts_str_build(char *bf, int bfsize,
                 u64 branch_count, u64 predicted_count,
                 u64 abort_count, u64 cycles_count,
                 u64 iter_count, u64 iter_cycles,
                 struct branch_type_stat *brtype_stat)
{
    int printed;

    if (branch_count == 0)
        return scnprintf(bf, bfsize, " (calltrace)");

    if (brtype_stat->branch_to) {
        printed = branch_to_str(bf, bfsize, branch_count,
                predicted_count, abort_count, brtype_stat);
    } else {
        printed = branch_from_str(bf, bfsize, branch_count,
                cycles_count, iter_count, iter_cycles);
    }

    if (!printed)
        bf[0] = 0;

    return printed;
}

static int callchain_counts_printf(FILE *fp, char *bf, int bfsize,
                   u64 branch_count, u64 predicted_count,
                   u64 abort_count, u64 cycles_count,
                   u64 iter_count, u64 iter_cycles,
                   struct branch_type_stat *brtype_stat)
{
    char str[256];

    counts_str_build(str, sizeof(str), branch_count,
             predicted_count, abort_count, cycles_count,
             iter_count, iter_cycles, brtype_stat);

    if (fp)
        return fprintf(fp, "%s", str);

    return scnprintf(bf, bfsize, "%s", str);
}

int callchain_list_counts__printf_value(struct callchain_list *clist,
                    FILE *fp, char *bf, int bfsize)
{
    u64 branch_count, predicted_count;
    u64 abort_count, cycles_count;
    u64 iter_count, iter_cycles;

    branch_count = clist->branch_count;
    predicted_count = clist->predicted_count;
    abort_count = clist->abort_count;
    cycles_count = clist->cycles_count;
    iter_count = clist->iter_count;
    iter_cycles = clist->iter_cycles;

    return callchain_counts_printf(fp, bf, bfsize, branch_count,
                       predicted_count, abort_count,
                       cycles_count, iter_count, iter_cycles,
                       &clist->brtype_stat);
}

static void free_callchain_node(struct callchain_node *node)
{
    struct callchain_list *list, *tmp;
    struct callchain_node *child;
    struct rb_node *n;

    list_for_each_entry_safe(list, tmp, &node->parent_val, list) {
        list_del(&list->list);
        map__zput(list->ms.map);
        free(list);
    }

    list_for_each_entry_safe(list, tmp, &node->val, list) {
        list_del(&list->list);
        map__zput(list->ms.map);
        free(list);
    }

    n = rb_first(&node->rb_root_in);
    while (n) {
        child = container_of(n, struct callchain_node, rb_node_in);
        n = rb_next(n);
        rb_erase(&child->rb_node_in, &node->rb_root_in);

        free_callchain_node(child);
        free(child);
    }
}

void free_callchain(struct callchain_root *root)
{
    if (!symbol_conf.use_callchain)
        return;

    free_callchain_node(&root->node);
}

static u64 decay_callchain_node(struct callchain_node *node)
{
    struct callchain_node *child;
    struct rb_node *n;
    u64 child_hits = 0;

    n = rb_first(&node->rb_root_in);
    while (n) {
        child = container_of(n, struct callchain_node, rb_node_in);

        child_hits += decay_callchain_node(child);
        n = rb_next(n);
    }

    node->hit = (node->hit * 7) / 8;
    node->children_hit = child_hits;

    return node->hit;
}

void decay_callchain(struct callchain_root *root)
{
    if (!symbol_conf.use_callchain)
        return;

    decay_callchain_node(&root->node);
}

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;
            map__get(new->ms.map);
            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;
    }
    return 0;

out:
    list_for_each_entry_safe(chain, new, &head, list) {
        list_del(&chain->list);
        map__zput(chain->ms.map);
        free(chain);
    }
    return -ENOMEM;
}

int callchain_cursor__copy(struct callchain_cursor *dst,
               struct callchain_cursor *src)
{
    int rc = 0;

    callchain_cursor_reset(dst);
    callchain_cursor_commit(src);

    while (true) {
        struct callchain_cursor_node *node;

        node = callchain_cursor_current(src);
        if (node == NULL)
            break;

        rc = callchain_cursor_append(dst, node->ip, node->map, node->sym,
                         node->branch, &node->branch_flags,
                         node->nr_loop_iter,
                         node->iter_cycles,
                         node->branch_from, node->srcline);
        if (rc)
            break;

        callchain_cursor_advance(src);
    }

    return rc;
}