From 8bd508b001629a5d836987d9a0702a6bfc4fc705 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Thu, 19 Nov 2015 14:01:19 +0100 Subject: [PATCH] perf callchain: Add order support for libdw DWARF unwinder As reported by Milian, currently for DWARF unwind (both libdw and libunwind) we display callchain in callee order only. Adding the support to follow callchain order setup to libdw DWARF unwinder, so we could get following output for report: $ perf record --call-graph dwarf ls ... $ perf report --no-children --stdio 21.12% ls libc-2.21.so [.] __strcoll_l | ---__strcoll_l mpsort_with_tmp mpsort_with_tmp mpsort_with_tmp sort_files main __libc_start_main _start $ perf report --stdio --no-children -g caller 21.12% ls libc-2.21.so [.] __strcoll_l | ---_start __libc_start_main main sort_files mpsort_with_tmp mpsort_with_tmp mpsort_with_tmp __strcoll_l Reported-and-Tested-by: Milian Wolff Signed-off-by: Jiri Olsa Tested-by: Wang Nan Cc: David Ahern Cc: Jan Kratochvil Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20151119130119.GA26617@krava.brq.redhat.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/unwind-libdw.c | 53 ++++++++++++++++++++++++---------- tools/perf/util/unwind-libdw.h | 2 ++ 2 files changed, 40 insertions(+), 15 deletions(-) diff --git a/tools/perf/util/unwind-libdw.c b/tools/perf/util/unwind-libdw.c index 2dcfe9a7c8d0..db8142ba7cb9 100644 --- a/tools/perf/util/unwind-libdw.c +++ b/tools/perf/util/unwind-libdw.c @@ -11,6 +11,7 @@ #include #include "event.h" #include "perf_regs.h" +#include "callchain.h" static char *debuginfo_path; @@ -52,25 +53,28 @@ static int report_module(u64 ip, struct unwind_info *ui) return __report_module(&al, ip, ui); } +/* + * Store all entries within entries array, + * we will process it after we finish unwind. + */ static int entry(u64 ip, struct unwind_info *ui) { - struct unwind_entry e; + struct unwind_entry *e = &ui->entries[ui->idx++]; struct addr_location al; if (__report_module(&al, ip, ui)) return -1; - e.ip = ip; - e.map = al.map; - e.sym = al.sym; + e->ip = ip; + e->map = al.map; + e->sym = al.sym; pr_debug("unwind: %s:ip = 0x%" PRIx64 " (0x%" PRIx64 ")\n", al.sym ? al.sym->name : "''", ip, al.map ? al.map->map_ip(al.map, ip) : (u64) 0); - - return ui->cb(&e, ui->arg); + return 0; } static pid_t next_thread(Dwfl *dwfl, void *arg, void **thread_argp) @@ -168,7 +172,7 @@ int unwind__get_entries(unwind_entry_cb_t cb, void *arg, struct perf_sample *data, int max_stack) { - struct unwind_info ui = { + struct unwind_info *ui, ui_buf = { .sample = data, .thread = thread, .machine = thread->mg->machine, @@ -177,35 +181,54 @@ int unwind__get_entries(unwind_entry_cb_t cb, void *arg, .max_stack = max_stack, }; Dwarf_Word ip; - int err = -EINVAL; + int err = -EINVAL, i; if (!data->user_regs.regs) return -EINVAL; - ui.dwfl = dwfl_begin(&offline_callbacks); - if (!ui.dwfl) + ui = zalloc(sizeof(ui_buf) + sizeof(ui_buf.entries[0]) * max_stack); + if (!ui) + return -ENOMEM; + + *ui = ui_buf; + + ui->dwfl = dwfl_begin(&offline_callbacks); + if (!ui->dwfl) goto out; err = perf_reg_value(&ip, &data->user_regs, PERF_REG_IP); if (err) goto out; - err = report_module(ip, &ui); + err = report_module(ip, ui); if (err) goto out; - if (!dwfl_attach_state(ui.dwfl, EM_NONE, thread->tid, &callbacks, &ui)) + if (!dwfl_attach_state(ui->dwfl, EM_NONE, thread->tid, &callbacks, ui)) goto out; - err = dwfl_getthread_frames(ui.dwfl, thread->tid, frame_callback, &ui); + err = dwfl_getthread_frames(ui->dwfl, thread->tid, frame_callback, ui); - if (err && !ui.max_stack) + if (err && !ui->max_stack) err = 0; + /* + * Display what we got based on the order setup. + */ + for (i = 0; i < ui->idx && !err; i++) { + int j = i; + + if (callchain_param.order == ORDER_CALLER) + j = ui->idx - i - 1; + + err = ui->entries[j].ip ? ui->cb(&ui->entries[j], ui->arg) : 0; + } + out: if (err) pr_debug("unwind: failed with '%s'\n", dwfl_errmsg(-1)); - dwfl_end(ui.dwfl); + dwfl_end(ui->dwfl); + free(ui); return 0; } diff --git a/tools/perf/util/unwind-libdw.h b/tools/perf/util/unwind-libdw.h index 417a1426f3ad..58328669ed16 100644 --- a/tools/perf/util/unwind-libdw.h +++ b/tools/perf/util/unwind-libdw.h @@ -16,6 +16,8 @@ struct unwind_info { unwind_entry_cb_t cb; void *arg; int max_stack; + int idx; + struct unwind_entry entries[]; }; #endif /* __PERF_UNWIND_LIBDW_H */ -- 2.20.1