[PATCH 11/16] perf intel-pt: Add support for synthesizing callchains for regular events

From: Adrian Hunter
Date: Wed Apr 01 2020 - 06:17:57 EST


Currently, callchains can be synthesized only for synthesized events.
Support also synthesizing callchains for regular events.

Example:

# perf record --kcore --aux-sample -e '{intel_pt//,cycles}' -c 10000 uname
Linux
[ perf record: Woken up 3 times to write data ]
[ perf record: Captured and wrote 0.532 MB perf.data ]
# perf script --itrace=Ge | head -20
uname 4864 2419025.358181: 10000 cycles:
ffffffffbba56965 apparmor_bprm_committing_creds+0x35 ([kernel.kallsyms])
ffffffffbc400cd5 __indirect_thunk_start+0x5 ([kernel.kallsyms])
ffffffffbba07422 security_bprm_committing_creds+0x22 ([kernel.kallsyms])
ffffffffbb89805d install_exec_creds+0xd ([kernel.kallsyms])
ffffffffbb90d9ac load_elf_binary+0x3ac ([kernel.kallsyms])

uname 4864 2419025.358185: 10000 cycles:
ffffffffbba56db0 apparmor_bprm_committed_creds+0x20 ([kernel.kallsyms])
ffffffffbc400cd5 __indirect_thunk_start+0x5 ([kernel.kallsyms])
ffffffffbba07452 security_bprm_committed_creds+0x22 ([kernel.kallsyms])
ffffffffbb89809a install_exec_creds+0x4a ([kernel.kallsyms])
ffffffffbb90d9ac load_elf_binary+0x3ac ([kernel.kallsyms])

uname 4864 2419025.358189: 10000 cycles:
ffffffffbb86fdf6 vma_adjust_trans_huge+0x6 ([kernel.kallsyms])
ffffffffbb821660 __vma_adjust+0x160 ([kernel.kallsyms])
ffffffffbb897be7 shift_arg_pages+0x97 ([kernel.kallsyms])
ffffffffbb897ed9 setup_arg_pages+0x1e9 ([kernel.kallsyms])
ffffffffbb90d9f2 load_elf_binary+0x3f2 ([kernel.kallsyms])

Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
---
tools/perf/util/intel-pt.c | 68 ++++++++++++++++++++++++++++++++++----
1 file changed, 61 insertions(+), 7 deletions(-)

diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c
index db25c77d82f3..a659b4a1b3f2 100644
--- a/tools/perf/util/intel-pt.c
+++ b/tools/perf/util/intel-pt.c
@@ -124,6 +124,8 @@ struct intel_pt {

struct range *time_ranges;
unsigned int range_cnt;
+
+ struct ip_callchain *chain;
};

enum switch_state {
@@ -868,6 +870,45 @@ static u64 intel_pt_ns_to_ticks(const struct intel_pt *pt, u64 ns)
pt->tc.time_mult;
}

+static struct ip_callchain *intel_pt_alloc_chain(struct intel_pt *pt)
+{
+ size_t sz = sizeof(struct ip_callchain);
+
+ /* Add 1 to callchain_sz for callchain context */
+ sz += (pt->synth_opts.callchain_sz + 1) * sizeof(u64);
+ return zalloc(sz);
+}
+
+static int intel_pt_callchain_init(struct intel_pt *pt)
+{
+ struct evsel *evsel;
+
+ evlist__for_each_entry(pt->session->evlist, evsel) {
+ if (!(evsel->core.attr.sample_type & PERF_SAMPLE_CALLCHAIN))
+ evsel->synth_sample_type |= PERF_SAMPLE_CALLCHAIN;
+ }
+
+ pt->chain = intel_pt_alloc_chain(pt);
+ if (!pt->chain)
+ return -ENOMEM;
+
+ return 0;
+}
+
+static void intel_pt_add_callchain(struct intel_pt *pt,
+ struct perf_sample *sample)
+{
+ struct thread *thread = machine__findnew_thread(pt->machine,
+ sample->pid,
+ sample->tid);
+
+ thread_stack__sample_late(thread, sample->cpu, pt->chain,
+ pt->synth_opts.callchain_sz + 1, sample->ip,
+ pt->kernel_start);
+
+ sample->callchain = pt->chain;
+}
+
static struct intel_pt_queue *intel_pt_alloc_queue(struct intel_pt *pt,
unsigned int queue_nr)
{
@@ -880,11 +921,7 @@ static struct intel_pt_queue *intel_pt_alloc_queue(struct intel_pt *pt,
return NULL;

if (pt->synth_opts.callchain) {
- size_t sz = sizeof(struct ip_callchain);
-
- /* Add 1 to callchain_sz for callchain context */
- sz += (pt->synth_opts.callchain_sz + 1) * sizeof(u64);
- ptq->chain = zalloc(sz);
+ ptq->chain = intel_pt_alloc_chain(pt);
if (!ptq->chain)
goto out_free;
}
@@ -1992,7 +2029,8 @@ static int intel_pt_sample(struct intel_pt_queue *ptq)
if (!(state->type & INTEL_PT_BRANCH))
return 0;

- if (pt->synth_opts.callchain || pt->synth_opts.thread_stack)
+ if (pt->synth_opts.callchain || pt->synth_opts.add_callchain ||
+ pt->synth_opts.thread_stack)
thread_stack__event(ptq->thread, ptq->cpu, ptq->flags, state->from_ip,
state->to_ip, ptq->insn_len,
state->trace_nr);
@@ -2639,6 +2677,11 @@ static int intel_pt_process_event(struct perf_session *session,
if (err)
return err;

+ if (event->header.type == PERF_RECORD_SAMPLE) {
+ if (pt->synth_opts.add_callchain && !sample->callchain)
+ intel_pt_add_callchain(pt, sample);
+ }
+
if (event->header.type == PERF_RECORD_AUX &&
(event->aux.flags & PERF_AUX_FLAG_TRUNCATED) &&
pt->synth_opts.errors) {
@@ -2710,6 +2753,7 @@ static void intel_pt_free(struct perf_session *session)
session->auxtrace = NULL;
thread__put(pt->unknown_thread);
addr_filters__exit(&pt->filts);
+ zfree(&pt->chain);
zfree(&pt->filter);
zfree(&pt->time_ranges);
free(pt);
@@ -3348,6 +3392,7 @@ int intel_pt_process_auxtrace_info(union perf_event *event,
!session->itrace_synth_opts->inject) {
pt->synth_opts.branches = false;
pt->synth_opts.callchain = true;
+ pt->synth_opts.add_callchain = true;
}
pt->synth_opts.thread_stack =
session->itrace_synth_opts->thread_stack;
@@ -3380,14 +3425,22 @@ int intel_pt_process_auxtrace_info(union perf_event *event,
pt->branches_filter |= PERF_IP_FLAG_RETURN |
PERF_IP_FLAG_TRACE_BEGIN;

- if (pt->synth_opts.callchain && !symbol_conf.use_callchain) {
+ if ((pt->synth_opts.callchain || pt->synth_opts.add_callchain) &&
+ !symbol_conf.use_callchain) {
symbol_conf.use_callchain = true;
if (callchain_register_param(&callchain_param) < 0) {
symbol_conf.use_callchain = false;
pt->synth_opts.callchain = false;
+ pt->synth_opts.add_callchain = false;
}
}

+ if (pt->synth_opts.add_callchain) {
+ err = intel_pt_callchain_init(pt);
+ if (err)
+ goto err_delete_thread;
+ }
+
err = intel_pt_synth_events(pt, session);
if (err)
goto err_delete_thread;
@@ -3410,6 +3463,7 @@ int intel_pt_process_auxtrace_info(union perf_event *event,
return 0;

err_delete_thread:
+ zfree(&pt->chain);
thread__zput(pt->unknown_thread);
err_free_queues:
intel_pt_log_disable();
--
2.17.1