Messages in this thread Patch in this message | | | Date | Wed, 15 Dec 2021 16:37:47 +0000 | From | Mark Rutland <> | Subject | Re: [PATCH v4 4/6] perf tools: enable dwarf_callchain_users on arm64 |
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On Wed, Dec 15, 2021 at 03:11:36PM +0000, German Gomez wrote: > From: Alexandre Truong <alexandre.truong@arm.com> > > 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 <alexandre.truong@arm.com> > Signed-off-by: German Gomez <german.gomez@arm.com> > --- > tools/perf/builtin-report.c | 4 ++-- > tools/perf/builtin-script.c | 4 ++-- > tools/perf/util/callchain.c | 9 ++++++++- > tools/perf/util/callchain.h | 2 +- > 4 files changed, 13 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..aaab9a674807 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 +1612,13 @@ void callchain_param_setup(u64 sample_type) > else > callchain_param.record_mode = CALLCHAIN_FP; > } > + > + /* > + * It's possible to determine the caller of leaf frames with omitted > + * frame pointers on aarch64 using libunwind, so enable it. > + */
I reckon it's worth mentioning *why* we need to do this; how about:
/* * 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. */
Other than that, this looks fine to me!
Thanks, Mark.
> + 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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