kernel/linux.git/tools/perf/util/callchain.h, branch v7.1

perf callchain: Refactor callchain option parsing

2026-03-19T21:42:46+00:00

record_opts__parse_callchain is shared by builtin-record and builtin-trace, it is declared in callchain.h. Move the declaration to callchain.c for consistency with the header. In other cases make the option callback a small static stub that then calls into callchain.c. Make the no argument '-g' callchain option just a short-cut for '--call-graph fp' so that there is consistency in how the arguments are handled. This requires the const char* string to be strdup-ed in __parse_callchain_report_opt. For consistency also make parse_callchain_record use strdup and remove some unnecessary casts. Also, be more explicit about the '-g' behavior if there is a .perfconfig file setting. Signed-off-by: Ian Rogers Tested-by: Thomas Richter Signed-off-by: Namhyung Kim

perf callchain: Switch callchain_param_setup from an arch to an e_machine

2026-01-27T04:35:47+00:00

Increase use of e_machine by replacing callchain_param_setup's arch argument to be an e_machine typically read from the session. Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Leo Yan Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Shimin Guo Cc: Yujie Liu Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Merge deferred user callchains

2025-12-03T05:59:14+00:00

Save samples with deferred callchains in a separate list and deliver them after merging the user callchains. If users don't want to merge they can set tool->merge_deferred_callchains to false to prevent the behavior. With previous result, now perf script will show the merged callchains. $ perf script ... pwd 2312 121.163435: 249113 cpu/cycles/P: ffffffff845b78d8 __build_id_parse.isra.0+0x218 ([kernel.kallsyms]) ffffffff83bb5bf6 perf_event_mmap+0x2e6 ([kernel.kallsyms]) ffffffff83c31959 mprotect_fixup+0x1e9 ([kernel.kallsyms]) ffffffff83c31dc5 do_mprotect_pkey+0x2b5 ([kernel.kallsyms]) ffffffff83c3206f __x64_sys_mprotect+0x1f ([kernel.kallsyms]) ffffffff845e6692 do_syscall_64+0x62 ([kernel.kallsyms]) ffffffff8360012f entry_SYSCALL_64_after_hwframe+0x76 ([kernel.kallsyms]) 7f18fe337fa7 mprotect+0x7 (/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2) 7f18fe330e0f _dl_sysdep_start+0x7f (/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2) 7f18fe331448 _dl_start_user+0x0 (/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2) ... The old output can be get using --no-merge-callchain option. Also perf report can get the user callchain entry at the end. $ perf report --no-children --stdio -q -S __build_id_parse.isra.0 # symbol: __build_id_parse.isra.0 8.40% pwd [kernel.kallsyms] | ---__build_id_parse.isra.0 perf_event_mmap mprotect_fixup do_mprotect_pkey __x64_sys_mprotect do_syscall_64 entry_SYSCALL_64_after_hwframe mprotect _dl_sysdep_start _dl_start_user Reviewed-by: Ian Rogers Signed-off-by: Namhyung Kim

perf record: Add --call-graph fp,defer option for deferred callchains

2025-12-03T05:59:13+00:00

Add a new callchain record mode option for deferred callchains. For now it only works with FP (frame-pointer) mode. And add the missing feature detection logic to clear the flag on old kernels. $ perf record --call-graph fp,defer -vv true ... ------------------------------------------------------------ perf_event_attr: type 0 (PERF_TYPE_HARDWARE) size 136 config 0 (PERF_COUNT_HW_CPU_CYCLES) { sample_period, sample_freq } 4000 sample_type IP|TID|TIME|CALLCHAIN|PERIOD read_format ID|LOST disabled 1 inherit 1 mmap 1 comm 1 freq 1 enable_on_exec 1 task 1 sample_id_all 1 mmap2 1 comm_exec 1 ksymbol 1 bpf_event 1 defer_callchain 1 defer_output 1 ------------------------------------------------------------ sys_perf_event_open: pid 162755 cpu 0 group_fd -1 flags 0x8 sys_perf_event_open failed, error -22 switching off deferred callchain support Reviewed-by: Ian Rogers Signed-off-by: Namhyung Kim

perf callchain: Allow symbols to be optional when resolving a callchain

2024-09-10T20:32:47+00:00

In uses like 'perf inject' it is not necessary to gather the symbol for each call chain location, the map for the sample IP is wanted so that build IDs and the like can be injected. Make gathering the symbol in the callchain_cursor optional. For a 'perf inject -B' command this lowers the peak RSS from 54.1MB to 29.6MB by avoiding loading symbols. Signed-off-by: Ian Rogers Acked-by: Namhyung Kim Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Anne Macedo Cc: Casey Chen Cc: Colin Ian King Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Peter Zijlstra Cc: Sun Haiyong Link: https://lore.kernel.org/r/20240909203740.143492-5-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf callchain: Add a for_each callback style API

2024-08-13T18:28:19+00:00

Add a for_each callback style API to callchain with sample__for_each_callchain_node(). Possibly in the future such an API can avoid the overhead of constructing the call chain list. Signed-off-by: Ian Rogers Acked-by: Namhyung Kim Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Casey Chen Cc: Colin Ian King Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Peter Zijlstra Cc: Tom Zanussi Link: https://lore.kernel.org/r/20240812224119.744968-1-irogers@google.com [ Split from a larger patch that introduced the API and use it ] Signed-off-by: Arnaldo Carvalho de Melo

perf callchain: Minor layout changes to callchain_list

2023-10-25T20:39:32+00:00

Avoid 6 byte hole for padding. Place more frequently used fields first in an attempt to use just 1 cacheline in the common case. Before: ``` struct callchain_list { u64 ip; /* 0 8 */ struct map_symbol ms; /* 8 24 */ struct { _Bool unfolded; /* 32 1 */ _Bool has_children; /* 33 1 */ }; /* 32 2 */ /* XXX 6 bytes hole, try to pack */ u64 branch_count; /* 40 8 */ u64 from_count; /* 48 8 */ u64 predicted_count; /* 56 8 */ /* --- cacheline 1 boundary (64 bytes) --- */ u64 abort_count; /* 64 8 */ u64 cycles_count; /* 72 8 */ u64 iter_count; /* 80 8 */ u64 iter_cycles; /* 88 8 */ struct branch_type_stat * brtype_stat; /* 96 8 */ const char * srcline; /* 104 8 */ struct list_head list; /* 112 16 */ /* size: 128, cachelines: 2, members: 13 */ /* sum members: 122, holes: 1, sum holes: 6 */ }; ``` After: ``` struct callchain_list { struct list_head list; /* 0 16 */ u64 ip; /* 16 8 */ struct map_symbol ms; /* 24 24 */ const char * srcline; /* 48 8 */ u64 branch_count; /* 56 8 */ /* --- cacheline 1 boundary (64 bytes) --- */ u64 from_count; /* 64 8 */ u64 cycles_count; /* 72 8 */ u64 iter_count; /* 80 8 */ u64 iter_cycles; /* 88 8 */ struct branch_type_stat * brtype_stat; /* 96 8 */ u64 predicted_count; /* 104 8 */ u64 abort_count; /* 112 8 */ struct { _Bool unfolded; /* 120 1 */ _Bool has_children; /* 121 1 */ }; /* 120 2 */ /* size: 128, cachelines: 2, members: 13 */ /* padding: 6 */ }; ``` Signed-off-by: Ian Rogers Cc: K Prateek Nayak Cc: Ravi Bangoria Cc: Sandipan Das Cc: Anshuman Khandual Cc: German Gomez Cc: James Clark Cc: Nick Terrell Cc: Sean Christopherson Cc: Changbin Du Cc: liuwenyu Cc: Yang Jihong Cc: Masami Hiramatsu Cc: Miguel Ojeda Cc: Song Liu Cc: Leo Yan Cc: Kajol Jain Cc: Andi Kleen Cc: Kan Liang Cc: Athira Rajeev Cc: Yanteng Si Cc: Liam Howlett Cc: Paolo Bonzini Link: https://lore.kernel.org/r/20231024222353.3024098-11-irogers@google.com Signed-off-by: Namhyung Kim

perf callchain: Make brtype_stat in callchain_list optional

2023-10-25T20:39:08+00:00

struct callchain_list is 352bytes in size, 232 of which are brtype_stat. brtype_stat is only used for certain callchain_list items so make it optional, allocating when necessary. So that printing doesn't need to deal with an optional brtype_stat, pass an empty/zero version. Before: ``` struct callchain_list { u64 ip; /* 0 8 */ struct map_symbol ms; /* 8 24 */ struct { _Bool unfolded; /* 32 1 */ _Bool has_children; /* 33 1 */ }; /* 32 2 */ /* XXX 6 bytes hole, try to pack */ u64 branch_count; /* 40 8 */ u64 from_count; /* 48 8 */ u64 predicted_count; /* 56 8 */ /* --- cacheline 1 boundary (64 bytes) --- */ u64 abort_count; /* 64 8 */ u64 cycles_count; /* 72 8 */ u64 iter_count; /* 80 8 */ u64 iter_cycles; /* 88 8 */ struct branch_type_stat brtype_stat; /* 96 232 */ /* --- cacheline 5 boundary (320 bytes) was 8 bytes ago --- */ const char * srcline; /* 328 8 */ struct list_head list; /* 336 16 */ /* size: 352, cachelines: 6, members: 13 */ /* sum members: 346, holes: 1, sum holes: 6 */ /* last cacheline: 32 bytes */ }; ``` After: ``` struct callchain_list { u64 ip; /* 0 8 */ struct map_symbol ms; /* 8 24 */ struct { _Bool unfolded; /* 32 1 */ _Bool has_children; /* 33 1 */ }; /* 32 2 */ /* XXX 6 bytes hole, try to pack */ u64 branch_count; /* 40 8 */ u64 from_count; /* 48 8 */ u64 predicted_count; /* 56 8 */ /* --- cacheline 1 boundary (64 bytes) --- */ u64 abort_count; /* 64 8 */ u64 cycles_count; /* 72 8 */ u64 iter_count; /* 80 8 */ u64 iter_cycles; /* 88 8 */ struct branch_type_stat * brtype_stat; /* 96 8 */ const char * srcline; /* 104 8 */ struct list_head list; /* 112 16 */ /* size: 128, cachelines: 2, members: 13 */ /* sum members: 122, holes: 1, sum holes: 6 */ }; ``` Signed-off-by: Ian Rogers Cc: K Prateek Nayak Cc: Ravi Bangoria Cc: Sandipan Das Cc: Anshuman Khandual Cc: German Gomez Cc: James Clark Cc: Nick Terrell Cc: Sean Christopherson Cc: Changbin Du Cc: liuwenyu Cc: Yang Jihong Cc: Masami Hiramatsu Cc: Miguel Ojeda Cc: Song Liu Cc: Leo Yan Cc: Kajol Jain Cc: Andi Kleen Cc: Kan Liang Cc: Athira Rajeev Cc: Yanteng Si Cc: Liam Howlett Cc: Paolo Bonzini Link: https://lore.kernel.org/r/20231024222353.3024098-10-irogers@google.com Signed-off-by: Namhyung Kim

perf callchain: Use pthread keys for tls callchain_cursor

2023-06-12T18:57:54+00:00

Pthread keys are more portable than __thread and allow the association of a destructor with the key. Use the destructor to clean up TLS callchain cursors to aid understanding memory leaks. Committer notes: Had to fixup a series of unconverted places and also check for the return of get_tls_callchain_cursor() as it may fail and return NULL. In that unlikely case we now either print something to a file, if the caller was expecting to print a callchain, or return an error code to state that resolving the callchain isn't possible. In some cases this was made easier because thread__resolve_callchain() already can fail for other reasons, so this new one (cursor == NULL) can be added and the callers don't have to explicitely check for this new condition. Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ali Saidi Cc: Andi Kleen Cc: Athira Rajeev Cc: Brian Robbins Cc: Changbin Du Cc: Dmitrii Dolgov <9erthalion6@gmail.com> Cc: Fangrui Song Cc: German Gomez Cc: Ingo Molnar Cc: Ivan Babrou Cc: James Clark Cc: Jing Zhang Cc: Jiri Olsa Cc: John Garry Cc: K Prateek Nayak Cc: Kan Liang Cc: Leo Yan Cc: Liam Howlett Cc: Mark Rutland Cc: Miguel Ojeda Cc: Mike Leach Cc: Namhyung Kim Cc: Naveen N. Rao Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Sean Christopherson Cc: Steinar H. Gunderson Cc: Suzuki Poulouse Cc: Wenyu Liu Cc: Will Deacon Cc: Yang Jihong Cc: Ye Xingchen Cc: Yuan Can Cc: coresight@lists.linaro.org Cc: linux-arm-kernel@lists.infradead.org Link: https://lore.kernel.org/r/20230608232823.4027869-25-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf callchain: Enable dwarf_callchain_users on arm64

2021-12-21T21:35:44+00:00

Enable dwarf_callchain_users on arm64 which will be needed to do a DWARF unwind in order to get the caller of the leaf frame. Reviewed-by: James Clark Signed-off-by: Alexandre Truong Acked-by: Jiri Olsa Cc: Alexander Shishkin Cc: John Garry Cc: Leo Yan Cc: Mark Rutland Cc: Mathieu Poirier Cc: Namhyung Kim Cc: Will Deacon Cc: linux-arm-kernel@lists.infradead.org Link: https://lore.kernel.org/r/20211217154521.80603-5-german.gomez@arm.com Signed-off-by: German Gomez Signed-off-by: Arnaldo Carvalho de Melo