[PATCH v5 4/6] perf tools: enable dwarf_callchain_users on arm64
From: German Gomez <hidden>
Date: 2021-12-17 15:45:49
Also in:
linux-perf-users, lkml
Subsystem:
performance events subsystem, the rest · Maintainers:
Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Linus Torvalds
From: Alexandre Truong <redacted> On arm64, enable dwarf_callchain_users which will be needed to do a dwarf unwind in order to get the caller of the leaf frame. Signed-off-by: Alexandre Truong <redacted> Signed-off-by: German Gomez <redacted> --- tools/perf/builtin-report.c | 4 ++-- tools/perf/builtin-script.c | 4 ++-- tools/perf/util/callchain.c | 14 +++++++++++++- tools/perf/util/callchain.h | 2 +- 4 files changed, 18 insertions(+), 6 deletions(-)
diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index 8167ebfe776a..a31ad60ba66e 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c@@ -410,7 +410,7 @@ static int report__setup_sample_type(struct report *rep) } } - callchain_param_setup(sample_type); + callchain_param_setup(sample_type, perf_env__arch(&rep->session->header.env)); if (rep->stitch_lbr && (callchain_param.record_mode != CALLCHAIN_LBR)) { ui__warning("Can't find LBR callchain. Switch off --stitch-lbr.\n"
@@ -1124,7 +1124,7 @@ static int process_attr(struct perf_tool *tool __maybe_unused, * on events sample_type. */ sample_type = evlist__combined_sample_type(*pevlist); - callchain_param_setup(sample_type); + callchain_param_setup(sample_type, perf_env__arch((*pevlist)->env)); return 0; }
diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index ab7d575f97f2..d308adfd1176 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c@@ -2318,7 +2318,7 @@ static int process_attr(struct perf_tool *tool, union perf_event *event, * on events sample_type. */ sample_type = evlist__combined_sample_type(evlist); - callchain_param_setup(sample_type); + callchain_param_setup(sample_type, perf_env__arch((*pevlist)->env)); /* Enable fields for callchain entries */ if (symbol_conf.use_callchain &&
@@ -3468,7 +3468,7 @@ static void script__setup_sample_type(struct perf_script *script) struct perf_session *session = script->session; u64 sample_type = evlist__combined_sample_type(session->evlist); - callchain_param_setup(sample_type); + callchain_param_setup(sample_type, perf_env__arch(session->machines.host.env)); if (script->stitch_lbr && (callchain_param.record_mode != CALLCHAIN_LBR)) { pr_warning("Can't find LBR callchain. Switch off --stitch-lbr.\n"
diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index 8e2777133bd9..131207b91d15 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c@@ -1600,7 +1600,7 @@ void callchain_cursor_reset(struct callchain_cursor *cursor) map__zput(node->ms.map); } -void callchain_param_setup(u64 sample_type) +void callchain_param_setup(u64 sample_type, const char *arch) { if (symbol_conf.use_callchain || symbol_conf.cumulate_callchain) { if ((sample_type & PERF_SAMPLE_REGS_USER) &&
@@ -1612,6 +1612,18 @@ void callchain_param_setup(u64 sample_type) else callchain_param.record_mode = CALLCHAIN_FP; } + + /* + * It's necessary to use libunwind to reliably determine the caller of + * a leaf function on aarch64, as otherwise we cannot know whether to + * start from the LR or FP. + * + * Always starting from the LR can result in duplicate or entirely + * erroneous entries. Always skipping the LR and starting from the FP + * can result in missing entries. + */ + if (callchain_param.record_mode == CALLCHAIN_FP && !strcmp(arch, "arm64")) + dwarf_callchain_users = true; } static bool chain_match(struct callchain_list *base_chain,
diff --git a/tools/perf/util/callchain.h b/tools/perf/util/callchain.h
index 77fba053c677..d95615daed73 100644
--- a/tools/perf/util/callchain.h
+++ b/tools/perf/util/callchain.h@@ -300,7 +300,7 @@ int callchain_branch_counts(struct callchain_root *root, u64 *branch_count, u64 *predicted_count, u64 *abort_count, u64 *cycles_count); -void callchain_param_setup(u64 sample_type); +void callchain_param_setup(u64 sample_type, const char *arch); bool callchain_cnode_matched(struct callchain_node *base_cnode, struct callchain_node *pair_cnode);
--
2.25.1
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