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

From: Leo Yan <[email-masked]>
Date: Sat, 5 Oct 2019 17:16:13 +0800

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 <[email-masked]>
---
 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

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