linux/tools/perf/util/callchain.c
Kan Liang aad2b21c15 perf tools: Enable LBR call stack support
Currently, there are two call chain recording options, fp and dwarf.

Haswell has a new feature that utilizes the existing LBR facility to
record call chains. Kernel side LBR support code provides this as a
third option to record call chains. This patch enables the lbr call
stack support on the tooling side.

LBR call stack has some limitations:

 - It reuses current LBR facility, so LBR call stack and branch record
   can not be enabled at the same time.

 - It is only available for user-space callchains.

However, it also offers some advantages:

 - LBR call stack can work on user apps which don't have frame-pointers
   or dwarf debug info compiled. It is a good alternative when nothing
   else works.

Tested-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Jacob Shin <jacob.w.shin@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masanari Iida <standby24x7@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rodrigo Campos <rodrigo@sdfg.com.ar>
Cc: Stephane Eranian <eranian@google.com>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1420482185-29830-2-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-02-18 17:16:17 +01:00

882 lines
20 KiB
C

/*
* 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 <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"
__thread struct callchain_cursor callchain_cursor;
#ifdef HAVE_DWARF_UNWIND_SUPPORT
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;
}
#endif /* HAVE_DWARF_UNWIND_SUPPORT */
int parse_callchain_record_opt(const char *arg)
{
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)) {
callchain_param.record_mode = CALLCHAIN_FP;
ret = 0;
} else
pr_err("callchain: No more arguments "
"needed for --call-graph fp\n");
break;
#ifdef HAVE_DWARF_UNWIND_SUPPORT
/* Dwarf style */
} else if (!strncmp(name, "dwarf", sizeof("dwarf"))) {
const unsigned long default_stack_dump_size = 8192;
ret = 0;
callchain_param.record_mode = CALLCHAIN_DWARF;
callchain_param.dump_size = default_stack_dump_size;
tok = strtok_r(NULL, ",", &saveptr);
if (tok) {
unsigned long size = 0;
ret = get_stack_size(tok, &size);
callchain_param.dump_size = size;
}
#endif /* HAVE_DWARF_UNWIND_SUPPORT */
} else if (!strncmp(name, "lbr", sizeof("lbr"))) {
if (!strtok_r(NULL, ",", &saveptr)) {
callchain_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;
}
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;
}
return -1;
}
static int parse_callchain_order(const char *value)
{
if (!strncmp(value, "caller", strlen(value))) {
callchain_param.order = ORDER_CALLER;
return 0;
}
if (!strncmp(value, "callee", strlen(value))) {
callchain_param.order = ORDER_CALLEE;
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, "branch", strlen(value))) {
callchain_param.branch_callstack = 1;
return 0;
}
return -1;
}
int
parse_callchain_report_opt(const char *arg)
{
char *tok;
char *endptr;
bool minpcnt_set = false;
symbol_conf.use_callchain = true;
if (!arg)
return 0;
while ((tok = strtok((char *)arg, ",")) != NULL) {
if (!strncmp(tok, "none", strlen(tok))) {
callchain_param.mode = CHAIN_NONE;
symbol_conf.use_callchain = false;
return 0;
}
if (!parse_callchain_mode(tok) ||
!parse_callchain_order(tok) ||
!parse_callchain_sort_key(tok)) {
/* parsing ok - move on to the next */
} 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;
}
arg = NULL;
}
if (callchain_register_param(&callchain_param) < 0) {
pr_err("Can't register callchain params\n");
return -1;
}
return 0;
}
int perf_callchain_config(const char *var, const char *value)
{
char *endptr;
if (prefixcmp(var, "call-graph."))
return 0;
var += sizeof("call-graph.") - 1;
if (!strcmp(var, "record-mode"))
return parse_callchain_record_opt(value);
#ifdef HAVE_DWARF_UNWIND_SUPPORT
if (!strcmp(var, "dump-size")) {
unsigned long size = 0;
int ret;
ret = get_stack_size(value, &size);
callchain_param.dump_size = size;
return ret;
}
#endif
if (!strcmp(var, "print-type"))
return parse_callchain_mode(value);
if (!strcmp(var, "order"))
return parse_callchain_order(value);
if (!strcmp(var, "sort-key"))
return parse_callchain_sort_key(value);
if (!strcmp(var, "threshold")) {
callchain_param.min_percent = strtod(value, &endptr);
if (value == endptr)
return -1;
}
if (!strcmp(var, "print-limit")) {
callchain_param.print_limit = strtod(value, &endptr);
if (value == endptr)
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:
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)
{
__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:
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);
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 void
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;
}
call->ip = cursor_node->ip;
call->ms.sym = cursor_node->sym;
call->ms.map = cursor_node->map;
list_add_tail(&call->list, &node->val);
callchain_cursor_advance(cursor);
cursor_node = callchain_cursor_current(cursor);
}
}
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);
fill_node(new, cursor);
new->children_hit = 0;
new->hit = period;
return new;
}
static s64 match_chain(struct callchain_cursor_node *node,
struct callchain_list *cnode)
{
struct symbol *sym = node->sym;
if (cnode->ms.sym && sym &&
callchain_param.key == CCKEY_FUNCTION)
return cnode->ms.sym->start - sym->start;
else
return cnode->ip - node->ip;
}
/*
* 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 void
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);
/* 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;
/* 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;
node = callchain_cursor_current(cursor);
new = add_child(parent, cursor, period);
/*
* 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) < 0)
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;
}
}
static int
append_chain(struct callchain_node *root,
struct callchain_cursor *cursor,
u64 period);
static void
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;
/* lookup in childrens */
while (*p) {
s64 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 == 0)
goto inc_children_hit;
if (ret < 0)
p = &parent->rb_left;
else
p = &parent->rb_right;
}
/* nothing in children, add to the current node */
rnode = add_child(root, cursor, period);
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;
}
static int
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;
int cmp = 0;
/*
* 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)
break;
found = true;
callchain_cursor_advance(cursor);
}
/* matches not, relay no the parent */
if (!found) {
WARN_ONCE(!cmp, "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) {
split_add_child(root, cursor, cnode, start, matches, period);
return 0;
}
/* we match 100% of the path, increment the hit */
if (matches == root->val_nr && cursor->pos == cursor->nr) {
root->hit += period;
return 0;
}
/* We match the node and still have a part remaining */
append_chain_children(root, cursor, period);
return 0;
}
int callchain_append(struct callchain_root *root,
struct callchain_cursor *cursor,
u64 period)
{
if (!cursor->nr)
return 0;
callchain_cursor_commit(cursor);
append_chain_children(&root->node, cursor, period);
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);
list_del(&list->list);
free(list);
}
if (src->hit) {
callchain_cursor_commit(cursor);
append_chain_children(dst, cursor, src->hit);
}
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)
{
struct callchain_cursor_node *node = *cursor->last;
if (!node) {
node = calloc(1, sizeof(*node));
if (!node)
return -ENOMEM;
*cursor->last = node;
}
node->ip = ip;
node->map = map;
node->sym = sym;
cursor->nr++;
cursor->last = &node->next;
return 0;
}
int sample__resolve_callchain(struct perf_sample *sample, struct symbol **parent,
struct perf_evsel *evsel, struct addr_location *al,
int max_stack)
{
if (sample->callchain == NULL)
return 0;
if (symbol_conf.use_callchain || symbol_conf.cumulate_callchain ||
sort__has_parent) {
return thread__resolve_callchain(al->thread, 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)
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;
if (node->map)
al->addr = node->map->map_ip(node->map, node->ip);
else
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)
{
int printed;
if (cl->ms.sym) {
if (callchain_param.key == CCKEY_ADDRESS &&
cl->ms.map && !cl->srcline)
cl->srcline = get_srcline(cl->ms.map->dso,
map__rip_2objdump(cl->ms.map,
cl->ip),
cl->ms.sym, false);
if (cl->srcline)
printed = scnprintf(bf, bfsize, "%s %s",
cl->ms.sym->name, cl->srcline);
else
printed = scnprintf(bf, bfsize, "%s", cl->ms.sym->name);
} 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;
}
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->val, list) {
list_del(&list->list);
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);
}