[PATCH v3 5/6] perf cs-etm: Support callchain for instruction sample

Leo Yan
2019-10-05T09:18:46Z

Now CoreSight has supported the thread stack; based on the thread stack
we can synthesize call chain for the instruction sample; the call chain
can be injected by option '--itrace=g'.

Before:

# perf script --itrace=g16l64i100
main 1579 100 instructions: ffff0000102137f0 group_sched_in+0xb0 ([kernel.kallsyms])
main 1579 100 instructions: ffff000010213b78 flexible_sched_in+0xf0 ([kernel.kallsyms])
main 1579 100 instructions: ffff0000102135ac event_sched_in.isra.57+0x74 ([kernel.kallsyms])
main 1579 100 instructions: ffff000010219344 perf_swevent_add+0x6c ([kernel.kallsyms])
main 1579 100 instructions: ffff000010214854 perf_event_update_userpage+0x4c ([kernel.kallsyms])
[...]

After:

# perf script --itrace=g16l64i100

main 1579 100 instructions:
ffff000010213b78 flexible_sched_in+0xf0 ([kernel.kallsyms])
ffff00001020c0b4 visit_groups_merge+0x12c ([kernel.kallsyms])

main 1579 100 instructions:
ffff0000102135ac event_sched_in.isra.57+0x74 ([kernel.kallsyms])
ffff0000102137a0 group_sched_in+0x60 ([kernel.kallsyms])
ffff000010213b84 flexible_sched_in+0xfc ([kernel.kallsyms])
ffff00001020c0b4 visit_groups_merge+0x12c ([kernel.kallsyms])

main 1579 100 instructions:
ffff000010219344 perf_swevent_add+0x6c ([kernel.kallsyms])
ffff0000102135f4 event_sched_in.isra.57+0xbc ([kernel.kallsyms])
ffff0000102137a0 group_sched_in+0x60 ([kernel.kallsyms])
ffff000010213b84 flexible_sched_in+0xfc ([kernel.kallsyms])
ffff00001020c0b4 visit_groups_merge+0x12c ([kernel.kallsyms])
[...]

Signed-off-by: Leo Yan <leo.yan@linaro.org>
---
tools/perf/util/cs-etm.c | 35 +++++++++++++++++++++++++++++++++--
1 file changed, 33 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
index 4b42f9c9bd34..56e501cd2f5f 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -17,6 +17,7 @@
#include <stdlib.h>

#include "auxtrace.h"
+#include "callchain.h"
#include "color.h"
#include "cs-etm.h"
#include "cs-etm-decoder/cs-etm-decoder.h"
@@ -74,6 +75,7 @@ struct cs_etm_traceid_queue {
size_t last_branch_pos;
union perf_event *event_buf;
struct thread *thread;
+ struct ip_callchain *chain;
struct branch_stack *last_branch;
struct branch_stack *last_branch_rb;
struct cs_etm_packet *prev_packet;
@@ -251,6 +253,16 @@ static int cs_etm__init_traceid_queue(struct cs_etm_queue *etmq,
if (!tidq->prev_packet)
goto out_free;

+ if (etm->synth_opts.callchain) {
+ size_t sz = sizeof(struct ip_callchain);
+
+ /* Add 1 to callchain_sz for callchain context */
+ sz += (etm->synth_opts.callchain_sz + 1) * sizeof(u64);
+ tidq->chain = zalloc(sz);
+ if (!tidq->chain)
+ goto out_free;
+ }
+
if (etm->synth_opts.last_branch) {
size_t sz = sizeof(struct branch_stack);

@@ -275,6 +287,7 @@ static int cs_etm__init_traceid_queue(struct cs_etm_queue *etmq,
zfree(&tidq->last_branch);
zfree(&tidq->prev_packet);
zfree(&tidq->packet);
+ zfree(&tidq->chain);
out:
return rc;
}
@@ -546,6 +559,7 @@ static void cs_etm__free_traceid_queues(struct cs_etm_queue *etmq)
zfree(&tidq->last_branch_rb);
zfree(&tidq->prev_packet);
zfree(&tidq->packet);
+ zfree(&tidq->chain);
zfree(&tidq);

/*
@@ -1126,7 +1140,7 @@ static void cs_etm__add_stack_event(struct cs_etm_queue *etmq,
int insn_len;
u64 from_ip, to_ip;

- if (etm->synth_opts.thread_stack) {
+ if (etm->synth_opts.callchain || etm->synth_opts.thread_stack) {
from_ip = cs_etm__last_executed_instr(tidq->prev_packet);
to_ip = cs_etm__first_executed_instr(tidq->packet);

@@ -1182,6 +1196,14 @@ static int cs_etm__synth_instruction_sample(struct cs_etm_queue *etmq,

cs_etm__copy_insn(etmq, tidq->trace_chan_id, tidq->packet, &sample);

+ if (etm->synth_opts.callchain) {
+ thread_stack__sample(tidq->thread, tidq->packet->cpu,
+ tidq->chain,
+ etm->synth_opts.callchain_sz + 1,
+ sample.ip, etm->kernel_start);
+ sample.callchain = tidq->chain;
+ }
+
if (etm->synth_opts.last_branch) {
cs_etm__copy_last_branch_rb(etmq, tidq);
sample.branch_stack = tidq->last_branch;
@@ -1369,6 +1391,8 @@ static int cs_etm__synth_events(struct cs_etm_auxtrace *etm,
attr.sample_type &= ~(u64)PERF_SAMPLE_ADDR;
}

+ if (etm->synth_opts.callchain)
+ attr.sample_type |= PERF_SAMPLE_CALLCHAIN;
if (etm->synth_opts.last_branch)
attr.sample_type |= PERF_SAMPLE_BRANCH_STACK;

@@ -2639,7 +2663,6 @@ int cs_etm__process_auxtrace_info(union perf_event *event,
} else {
itrace_synth_opts__set_default(&etm->synth_opts,
session->itrace_synth_opts->default_no_sample);
- etm->synth_opts.callchain = false;
etm->synth_opts.thread_stack =
session->itrace_synth_opts->thread_stack;
}
@@ -2651,6 +2674,14 @@ int cs_etm__process_auxtrace_info(union perf_event *event,
etm->branches_filter |= PERF_IP_FLAG_RETURN |
PERF_IP_FLAG_TRACE_BEGIN;

+ if (etm->synth_opts.callchain && !symbol_conf.use_callchain) {
+ symbol_conf.use_callchain = true;
+ if (callchain_register_param(&callchain_param) < 0) {
+ symbol_conf.use_callchain = false;
+ etm->synth_opts.callchain = false;
+ }
+ }
+
err = cs_etm__synth_events(etm, session);
if (err)
goto err_delete_thread;
--
2.17.1