| Message ID | 20211215151139.40854-5-german.gomez@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Fix missing leaf-function callers when recording | expand |
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 >
On 15/12/2021 16:37, Mark Rutland wrote: > On Wed, Dec 15, 2021 at 03:11:36PM +0000, German Gomez wrote: >> [...] >> >> + >> + /* >> + * 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. Ack, I will update this Thanks, German > >> + 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 >>
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. + */ + 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);