[tip:perf/core] perf intel-pt: Decoder to output CBR changes immediately

From: tip-bot for Adrian Hunter
Date: Wed Jul 03 2019 - 10:04:36 EST


Commit-ID: abe5a1d3e4bee361bd3b21b8909c8421e46911d1
Gitweb: https://git.kernel.org/tip/abe5a1d3e4bee361bd3b21b8909c8421e46911d1
Author: Adrian Hunter <adrian.hunter@xxxxxxxxx>
AuthorDate: Sat, 22 Jun 2019 12:32:42 +0300
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Tue, 25 Jun 2019 08:47:10 -0300

perf intel-pt: Decoder to output CBR changes immediately

The core-to-bus ratio (CBR) provides the CPU frequency. With branches
enabled, the decoder was outputting CBR changes only when there was a
branch. That loses the correct time of the change if the trace is not in
context (e.g. not tracing kernel space). Change to output the CBR change
immediately.

Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/20190622093248.581-2-adrian.hunter@xxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/util/intel-pt-decoder/intel-pt-decoder.c | 16 ++++++----------
1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
index f8b71bf2bb4c..3d2255f284f4 100644
--- a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
+++ b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
@@ -2015,16 +2015,8 @@ next:

case INTEL_PT_CBR:
intel_pt_calc_cbr(decoder);
- if (!decoder->branch_enable &&
- decoder->cbr != decoder->cbr_seen) {
- decoder->cbr_seen = decoder->cbr;
- decoder->state.type = INTEL_PT_CBR_CHG;
- decoder->state.from_ip = decoder->ip;
- decoder->state.to_ip = 0;
- decoder->state.cbr_payload =
- decoder->packet.payload;
+ if (decoder->cbr != decoder->cbr_seen)
return 0;
- }
break;

case INTEL_PT_MODE_EXEC:
@@ -2626,8 +2618,12 @@ const struct intel_pt_state *intel_pt_decode(struct intel_pt_decoder *decoder)
decoder->sample_tot_cyc_cnt = decoder->tot_cyc_cnt;
} else {
decoder->state.err = 0;
- if (decoder->cbr != decoder->cbr_seen && decoder->state.type) {
+ if (decoder->cbr != decoder->cbr_seen) {
decoder->cbr_seen = decoder->cbr;
+ if (!decoder->state.type) {
+ decoder->state.from_ip = decoder->ip;
+ decoder->state.to_ip = 0;
+ }
decoder->state.type |= INTEL_PT_CBR_CHG;
decoder->state.cbr_payload = decoder->cbr_payload;
}