From: Adrian Hunter adrian.hunter@intel.com
commit a58a057ce65b52125dd355b7d8b0d540ea267a5f upstream.
CBR events can result in a duplicate branch event, because the state type defaults to a branch. Fix by clearing the state type.
Example: trace 'sleep' and hope for a frequency change
Before:
$ perf record -e intel_pt//u sleep 0.1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.034 MB perf.data ] $ perf script --itrace=bpe > before.txt
After:
$ perf script --itrace=bpe > after.txt $ diff -u before.txt after.txt # --- before.txt 2020-07-07 14:42:18.191508098 +0300 # +++ after.txt 2020-07-07 14:42:36.587891753 +0300 @@ -29673,7 +29673,6 @@ sleep 93431 [007] 15411.619905: 1 branches:u: 0 [unknown] ([unknown]) => 7f0818abb2e0 clock_nanosleep@@GLIBC_2.17+0x0 (/usr/lib/x86_64-linux-gnu/libc-2.31.so) sleep 93431 [007] 15411.619905: 1 branches:u: 7f0818abb30c clock_nanosleep@@GLIBC_2.17+0x2c (/usr/lib/x86_64-linux-gnu/libc-2.31.so) => 0 [unknown] ([unknown]) sleep 93431 [007] 15411.720069: cbr: cbr: 15 freq: 1507 MHz ( 56%) 7f0818abb30c clock_nanosleep@@GLIBC_2.17+0x2c (/usr/lib/x86_64-linux-gnu/libc-2.31.so) - sleep 93431 [007] 15411.720069: 1 branches:u: 7f0818abb30c clock_nanosleep@@GLIBC_2.17+0x2c (/usr/lib/x86_64-linux-gnu/libc-2.31.so) => 0 [unknown] ([unknown]) sleep 93431 [007] 15411.720076: 1 branches:u: 0 [unknown] ([unknown]) => 7f0818abb30e clock_nanosleep@@GLIBC_2.17+0x2e (/usr/lib/x86_64-linux-gnu/libc-2.31.so) sleep 93431 [007] 15411.720077: 1 branches:u: 7f0818abb323 clock_nanosleep@@GLIBC_2.17+0x43 (/usr/lib/x86_64-linux-gnu/libc-2.31.so) => 7f0818ac0eb7 __nanosleep+0x17 (/usr/lib/x86_64-linux-gnu/libc-2.31.so) sleep 93431 [007] 15411.720077: 1 branches:u: 7f0818ac0ebf __nanosleep+0x1f (/usr/lib/x86_64-linux-gnu/libc-2.31.so) => 55cb7e4c2827 rpl_nanosleep+0x97 (/usr/bin/sleep)
Fixes: 91de8684f1cff ("perf intel-pt: Cater for CBR change in PSB+") Fixes: abe5a1d3e4bee ("perf intel-pt: Decoder to output CBR changes immediately") Signed-off-by: Adrian Hunter adrian.hunter@intel.com Reviewed-by: Andi Kleen ak@linux.intel.com Tested-by: Arnaldo Carvalho de Melo acme@redhat.com Cc: Jiri Olsa jolsa@redhat.com Cc: stable@vger.kernel.org Link: http://lore.kernel.org/lkml/20200710151104.15137-3-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- tools/perf/util/intel-pt-decoder/intel-pt-decoder.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
--- a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c +++ b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c @@ -1977,8 +1977,10 @@ next: * possibility of another CBR change that gets caught up * in the PSB+. */ - if (decoder->cbr != decoder->cbr_seen) + if (decoder->cbr != decoder->cbr_seen) { + decoder->state.type = 0; return 0; + } break;
case INTEL_PT_PIP: @@ -2019,8 +2021,10 @@ next:
case INTEL_PT_CBR: intel_pt_calc_cbr(decoder); - if (decoder->cbr != decoder->cbr_seen) + if (decoder->cbr != decoder->cbr_seen) { + decoder->state.type = 0; return 0; + } break;
case INTEL_PT_MODE_EXEC: