perf cs-etm module converts decoder elements to packets and then we have more context crossing packets to generate synthenize samples, finally perf tool can faciliate samples for statistics and report the results.
This patch series is to address several issues found related with packets handling and samples generation when worked firstly on branch sample flags support for Arm CoreSight trace data, so this patch series also is dependency for another patch series for sample flags.
The first two patches are mainly to fix issues in cs_etm__flush(): Patch 0001 corrects packets swapping in cs_etm__flush() and this can fix the wrong branch sample caused by the missed packets swapping; patch 0002 is to fix the wrong samples generation with stale packets at the end of every trace buffer.
Patch 0003 is used to support NO_SYNC packet, otherwise the trace decoding cannot reflect the tracing discontinuity caused by NO_SYNC packet.
Patch 0004/0005 has been published in the patch series 'perf cs-etm: Add support for sample flags' before but at this time I move them into this patch series due these two patches are more relative with packets handling. Patch 0004 is used to generate branch sample for exception packets; and patch 0005 is to track the exception number.
This patch series is applied on the acme's perf core branch [1] with the latest commit f1d23afaf677 ("perf bpf: Reduce the hardcoded .max_entries for pid_maps") and has one prerequisite from Rob's patch 'perf: Support for Arm A32/T32 instruction sets in CoreSight trace' [2].
With applying the dependency patch, this patch series has been tested for branch samples dumping with below command on Juno board:
# perf script -F,-time,+ip,+sym,+dso,+addr,+symoff -k vmlinux
[1] https://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git/log/?h=perf/c... [2] http://archive.armlinux.org.uk/lurker/message/20181109.091126.9d69489d.en.ht...
Leo Yan (5): perf cs-etm: Correct packets swapping in cs_etm__flush() perf cs-etm: Avoid stale branch samples when flush packet perf cs-etm: Support for NO_SYNC packet perf cs-etm: Generate branch sample for exception packet perf cs-etm: Track exception number
tools/perf/util/cs-etm-decoder/cs-etm-decoder.c | 91 ++++++++++++++++++++++--- tools/perf/util/cs-etm-decoder/cs-etm-decoder.h | 11 +-- tools/perf/util/cs-etm.c | 65 +++++++++++++++--- 3 files changed, 146 insertions(+), 21 deletions(-)