Subject: [PATCH v2 3/5] perf cs-etm: Support branch filter

From: Leo Yan <[email-masked]>
Date: Tue, 24 Sep 2019 00:07:57 +0800

If user specifies options -F,+callindent or call chain related options,
it means the user only cares about functions calls and returns; thus in
this case it's pointless to generate samples for other types of
branches.

To output only pairs of calls and returns, this patch introduces branch
filter and the filter is set according to synthetic options.  Finally,
perf can output only for calls and returns and without redundant
branches.

Before:

  # perf script -F,+callindent
            main  2808          1          branches:                 coresight_test1@plt                                  aaaaba8d37d8 main+0x14 (/root/coresight_test/main)
            main  2808          1          branches:                     coresight_test1@plt                              aaaaba8d367c coresight_test1@plt+0xc (/root/coresight_test/main)
            main  2808          1          branches:                     _init                                            aaaaba8d3650 _init+0x30 (/root/coresight_test/main)
            main  2808          1          branches:                     _dl_fixup                                        ffff86373b4c _dl_runtime_resolve+0x40 (/lib/aarch64-linux-gnu/ld-2.28.s
            main  2808          1          branches:                         _dl_lookup_symbol_x                          ffff8636e078 _dl_fixup+0xb8 (/lib/aarch64-linux-gnu/ld-2.28.so)
            main  2808          1          branches:                                                                      ffff8636a3f4 _dl_lookup_symbol_x+0x5c (/lib/aarch64-linux-gnu/ld-2.28.s
            main  2808          1          branches:                                                                      ffff8636a3f4 _dl_lookup_symbol_x+0x5c (/lib/aarch64-linux-gnu/ld-2.28.s
            main  2808          1          branches:                                                                      ffff8636a3f4 _dl_lookup_symbol_x+0x5c (/lib/aarch64-linux-gnu/ld-2.28.s
            main  2808          1          branches:                                                                      ffff8636a3f4 _dl_lookup_symbol_x+0x5c (/lib/aarch64-linux-gnu/ld-2.28.s
            main  2808          1          branches:                                                                      ffff8636a3f4 _dl_lookup_symbol_x+0x5c (/lib/aarch64-linux-gnu/ld-2.28.s
  [...]

After:

  # perf script -F,+callindent
            main  2808          1          branches:                 coresight_test1@plt                                  aaaaba8d37d8 main+0x14 (/root/coresight_test/main)
            main  2808          1          branches:                     _dl_fixup                                        ffff86373b4c _dl_runtime_resolve+0x40 (/lib/aarch64-linux-gnu/ld-2.28.s
            main  2808          1          branches:                         _dl_lookup_symbol_x                          ffff8636e078 _dl_fixup+0xb8 (/lib/aarch64-linux-gnu/ld-2.28.so)
            main  2808          1          branches:                             do_lookup_x                              ffff8636a49c _dl_lookup_symbol_x+0x104 (/lib/aarch64-linux-gnu/ld-2.28.
            main  2808          1          branches:                                 check_match                          ffff86369bf0 do_lookup_x+0x238 (/lib/aarch64-linux-gnu/ld-2.28.so)
            main  2808          1          branches:                                     strcmp                           ffff86369888 check_match+0x70 (/lib/aarch64-linux-gnu/ld-2.28.so)
            main  2808          1          branches:                 printf@plt                                           aaaaba8d37ec main+0x28 (/root/coresight_test/main)
            main  2808          1          branches:                     _dl_fixup                                        ffff86373b4c _dl_runtime_resolve+0x40 (/lib/aarch64-linux-gnu/ld-2.28.s
            main  2808          1          branches:                         _dl_lookup_symbol_x                          ffff8636e078 _dl_fixup+0xb8 (/lib/aarch64-linux-gnu/ld-2.28.so)
            main  2808          1          branches:                             do_lookup_x                              ffff8636a49c _dl_lookup_symbol_x+0x104 (/lib/aarch64-linux-gnu/ld-2.28.
            main  2808          1          branches:                                 _dl_name_match_p                     ffff86369af0 do_lookup_x+0x138 (/lib/aarch64-linux-gnu/ld-2.28.so)
            main  2808          1          branches:                                     strcmp                           ffff8636f7f0 _dl_name_match_p+0x18 (/lib/aarch64-linux-gnu/ld-2.28.so)
  [...]

Signed-off-by: Leo Yan <[email-masked]>
---
 tools/perf/util/cs-etm.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
index 6bdc9cd8293c..018c7e682ded 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -55,6 +55,7 @@ struct cs_etm_auxtrace {
 
 	int num_cpu;
 	u32 auxtrace_type;
+	u32 branches_filter;
 	u64 branches_sample_type;
 	u64 branches_id;
 	u64 instructions_sample_type;
@@ -1222,6 +1223,10 @@ static int cs_etm__synth_branch_sample(struct cs_etm_queue *etmq,
 	} dummy_bs;
 	u64 ip;
 
+	if (etm->branches_filter &&
+	    !(etm->branches_filter & tidq->prev_packet->flags))
+		return 0;
+
 	ip = cs_etm__last_executed_instr(tidq->prev_packet);
 
 	event->sample.header.type = PERF_RECORD_SAMPLE;
@@ -2638,6 +2643,13 @@ int cs_etm__process_auxtrace_info(union perf_event *event,
 				session->itrace_synth_opts->thread_stack;
 	}
 
+	if (etm->synth_opts.calls)
+		etm->branches_filter |= PERF_IP_FLAG_CALL | PERF_IP_FLAG_ASYNC |
+					PERF_IP_FLAG_TRACE_END;
+	if (etm->synth_opts.returns)
+		etm->branches_filter |= PERF_IP_FLAG_RETURN |
+					PERF_IP_FLAG_TRACE_BEGIN;
+
 	err = cs_etm__synth_events(etm, session);
 	if (err)
 		goto err_delete_thread;
-- 
2.17.1

_______________________________________________
linux-arm-kernel mailing list
[email-masked]
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel