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a60335ba32
When saving the callchain on Power, the kernel conservatively saves excess entries in the callchain. A few of these entries are needed in some cases but not others. We should use the DWARF debug information to determine when the entries are needed. Eg: the value in the link register (LR) is needed only when it holds the return address of a function. At other times it must be ignored. If the unnecessary entries are not ignored, we end up with duplicate arcs in the call-graphs. Use the DWARF debug information to determine if any callchain entries should be ignored when building call-graphs. Callgraph before the patch: 14.67% 2234 sprintft libc-2.18.so [.] __random | --- __random | |--61.12%-- __random | | | |--97.15%-- rand | | do_my_sprintf | | main | | generic_start_main.isra.0 | | __libc_start_main | | 0x0 | | | --2.85%-- do_my_sprintf | main | generic_start_main.isra.0 | __libc_start_main | 0x0 | --38.88%-- rand | |--94.01%-- rand | do_my_sprintf | main | generic_start_main.isra.0 | __libc_start_main | 0x0 | --5.99%-- do_my_sprintf main generic_start_main.isra.0 __libc_start_main 0x0 Callgraph after the patch: 14.67% 2234 sprintft libc-2.18.so [.] __random | --- __random | |--95.93%-- rand | do_my_sprintf | main | generic_start_main.isra.0 | __libc_start_main | 0x0 | --4.07%-- do_my_sprintf main generic_start_main.isra.0 __libc_start_main 0x0 TODO: For split-debug info objects like glibc, we can only determine the call-frame-address only when both .eh_frame and .debug_info sections are available. We should be able to determin the CFA even without the .eh_frame section. Fix suggested by Anton Blanchard. Thanks to valuable input on DWARF debug information from Ulrich Weigand. Reported-by: Maynard Johnson <maynard@us.ibm.com> Tested-by: Maynard Johnson <maynard@us.ibm.com> Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/20140625154903.GA29607@us.ibm.com Signed-off-by: Jiri Olsa <jolsa@kernel.org>
193 lines
4.6 KiB
C
193 lines
4.6 KiB
C
#ifndef __PERF_CALLCHAIN_H
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#define __PERF_CALLCHAIN_H
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#include "../perf.h"
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#include <linux/list.h>
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#include <linux/rbtree.h>
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#include "event.h"
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#include "symbol.h"
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enum perf_call_graph_mode {
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CALLCHAIN_NONE,
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CALLCHAIN_FP,
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CALLCHAIN_DWARF,
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CALLCHAIN_MAX
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};
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enum chain_mode {
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CHAIN_NONE,
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CHAIN_FLAT,
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CHAIN_GRAPH_ABS,
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CHAIN_GRAPH_REL
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};
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enum chain_order {
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ORDER_CALLER,
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ORDER_CALLEE
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};
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struct callchain_node {
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struct callchain_node *parent;
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struct list_head val;
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struct rb_node rb_node_in; /* to insert nodes in an rbtree */
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struct rb_node rb_node; /* to sort nodes in an output tree */
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struct rb_root rb_root_in; /* input tree of children */
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struct rb_root rb_root; /* sorted output tree of children */
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unsigned int val_nr;
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u64 hit;
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u64 children_hit;
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};
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struct callchain_root {
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u64 max_depth;
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struct callchain_node node;
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};
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struct callchain_param;
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typedef void (*sort_chain_func_t)(struct rb_root *, struct callchain_root *,
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u64, struct callchain_param *);
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enum chain_key {
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CCKEY_FUNCTION,
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CCKEY_ADDRESS
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};
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struct callchain_param {
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enum chain_mode mode;
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u32 print_limit;
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double min_percent;
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sort_chain_func_t sort;
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enum chain_order order;
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enum chain_key key;
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};
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struct callchain_list {
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u64 ip;
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struct map_symbol ms;
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struct list_head list;
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};
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/*
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* A callchain cursor is a single linked list that
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* let one feed a callchain progressively.
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* It keeps persistent allocated entries to minimize
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* allocations.
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*/
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struct callchain_cursor_node {
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u64 ip;
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struct map *map;
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struct symbol *sym;
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struct callchain_cursor_node *next;
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};
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struct callchain_cursor {
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u64 nr;
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struct callchain_cursor_node *first;
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struct callchain_cursor_node **last;
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u64 pos;
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struct callchain_cursor_node *curr;
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};
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extern __thread struct callchain_cursor callchain_cursor;
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static inline void callchain_init(struct callchain_root *root)
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{
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INIT_LIST_HEAD(&root->node.val);
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root->node.parent = NULL;
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root->node.hit = 0;
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root->node.children_hit = 0;
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root->node.rb_root_in = RB_ROOT;
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root->max_depth = 0;
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}
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static inline u64 callchain_cumul_hits(struct callchain_node *node)
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{
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return node->hit + node->children_hit;
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}
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int callchain_register_param(struct callchain_param *param);
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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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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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* Initialize a cursor before adding entries inside, but keep
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* the previously allocated entries as a cache.
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*/
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static inline void callchain_cursor_reset(struct callchain_cursor *cursor)
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{
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cursor->nr = 0;
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cursor->last = &cursor->first;
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}
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int callchain_cursor_append(struct callchain_cursor *cursor, u64 ip,
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struct map *map, struct symbol *sym);
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/* Close a cursor writing session. Initialize for the reader */
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static inline void callchain_cursor_commit(struct callchain_cursor *cursor)
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{
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cursor->curr = cursor->first;
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cursor->pos = 0;
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}
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/* Cursor reading iteration helpers */
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static inline struct callchain_cursor_node *
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callchain_cursor_current(struct callchain_cursor *cursor)
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{
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if (cursor->pos == cursor->nr)
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return NULL;
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return cursor->curr;
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}
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static inline void callchain_cursor_advance(struct callchain_cursor *cursor)
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{
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cursor->curr = cursor->curr->next;
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cursor->pos++;
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}
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struct option;
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struct hist_entry;
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int record_parse_callchain(const char *arg, struct record_opts *opts);
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int record_parse_callchain_opt(const struct option *opt, const char *arg, int unset);
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int record_callchain_opt(const struct option *opt, const char *arg, int unset);
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int sample__resolve_callchain(struct perf_sample *sample, struct symbol **parent,
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struct perf_evsel *evsel, struct addr_location *al,
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int max_stack);
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int hist_entry__append_callchain(struct hist_entry *he, struct perf_sample *sample);
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int fill_callchain_info(struct addr_location *al, struct callchain_cursor_node *node,
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bool hide_unresolved);
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extern const char record_callchain_help[];
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int parse_callchain_report_opt(const char *arg);
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static inline void callchain_cursor_snapshot(struct callchain_cursor *dest,
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struct callchain_cursor *src)
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{
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*dest = *src;
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dest->first = src->curr;
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dest->nr -= src->pos;
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}
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#ifdef HAVE_SKIP_CALLCHAIN_IDX
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extern int arch_skip_callchain_idx(struct machine *machine,
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struct thread *thread, struct ip_callchain *chain);
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#else
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static inline int arch_skip_callchain_idx(struct machine *machine __maybe_unused,
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struct thread *thread __maybe_unused,
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struct ip_callchain *chain __maybe_unused)
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{
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return -1;
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}
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#endif
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#endif /* __PERF_CALLCHAIN_H */
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