Re: [PATCH 00/10] perf tools: Add support for CoreSight trace decoding

[Leo Yan]

Hi Mathieu,

On Fri, Dec 15, 2017 at 09:44:49AM -0700, Mathieu Poirier wrote:
> This patchset adds support for per-thread CoreSight trace decoding from the
> "perf report" interface.  It is largely modelled on what has been done for 
> intelPT traces and currently targets the ETMv4 architecture.  Support for
> cpu-wide scenarios and ETMv3/PTMv1.1 will follow shortly.
> 
> The trace decoding support is done using the Open CoreSight Decoding
> Library (openCSD), a stand alone open source project available here [1].
> Integration of the openCSD library with the perf tools follow what has
> been done for other support libraries.  If the library has been installed
> on a system the build scripts will include support for CoreSight trace
> decoding:
> 
> ...                          zlib: [ on  ]
> ...                          lzma: [ OFF ]
> ...                     get_cpuid: [ on  ]
> ...                           bpf: [ on  ]
> ...                    libopencsd: [ on  ] <------
> 
> Instructions on how to build and install the openCSD library are provided
> in the HOWTO.md of the project repository.  We elected to keep the decoder
> library independent of the kernel tree as it is also used outside of the
> perf toolset and various non-linux projects.
> 
> The work applies cleanly to [2] and proper functionning of the feature
> depends on this patch [3].

With latest perf code, it reports another error when analyse perf
data: "0x3e0 [0x50]: failed to process type: 1".

After roughly analysis, I found this is caused by one dummy event (in
the binary from offset 0xf8 to offset 0x178). Because this event type
is not set for 'PERF_SAMPLE_TIME', so the function
perf_evsel__parse_sample_timestamp() checks the event has not set
'PERF_SAMPLE_TIME' then directly bail out with error.

000000f0: 0800 0000 0000 0000 0100 0000 7000 0000  ............p... 
00000100: 0900 0000 0000 0000 0100 0000 0000 0000  ................ 
00000110: 0300 0100 0000 0000 0400 0000 0000 0000  ................ 
00000120: 6133 8401 0000 0000 0000 0000 0000 0000  a3.............. 
00000130: 0000 0000 0000 0000 0000 0000 0000 0000  ................ 
00000140: 0000 0000 0000 0000 0000 0000 0000 0000  ................ 
00000150: 0000 0000 0000 0000 0000 0000 0000 0000  ................ 
00000160: 0000 0000 0000 0000 7000 0000 0000 0000  ........p....... 
00000170: 0800 0000 0000 0000 4600 0000 0000 6802  ........F.....h.

You could check the perf binary from [1]. Please note, this perf data
I capatured from kernel 4.14-rc6, so is it might be compatible issue
between 4.14-rc6 and 4.15?

[1] http://people.linaro.org/~leo.yan/binaries/perf_4.15_r4/perf.data

Thanks,
Leo Yan

> Review and comments would be greatly appreciated.
> 
> Regards,
> Mathieu
> 
> [1]. https://github.com/Linaro/OpenCSD
> [2]. git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git perf/core
> [3]. https://lkml.org/lkml/2017/12/14/612
> 
> Mathieu Poirier (8):
>   perf tools: Integrating the CoreSight decoding library
>   perf tools: Add initial entry point for decoder CoreSight traces
>   perf tools: Add decoder mechanic to support dumping trace data
>   perf tools: Add support for decoding CoreSight trace data
>   perf tools: Add functionality to communicate with the openCSD decoder
>   pert tools: Add queue management functionality
>   perf tools: Add full support for CoreSight trace decoding
>   perf tools: Add mechanic to synthesise CoreSight trace packets
> 
> Tor Jeremiassen (2):
>   perf tools: Add processing of coresight metadata
>   MAINTAINERS: Adding entry for CoreSight trace decoding
> 
>  MAINTAINERS                                     |    3 +-
>  tools/build/Makefile.feature                    |    6 +-
>  tools/build/feature/Makefile                    |    6 +-
>  tools/build/feature/test-all.c                  |    5 +
>  tools/build/feature/test-libopencsd.c           |    8 +
>  tools/perf/Makefile.config                      |   13 +
>  tools/perf/util/Build                           |    6 +
>  tools/perf/util/auxtrace.c                      |    2 +
>  tools/perf/util/cs-etm-decoder/Build            |    1 +
>  tools/perf/util/cs-etm-decoder/cs-etm-decoder.c |  513 ++++++++++++
>  tools/perf/util/cs-etm-decoder/cs-etm-decoder.h |  105 +++
>  tools/perf/util/cs-etm.c                        | 1023 +++++++++++++++++++++++
>  tools/perf/util/cs-etm.h                        |   18 +
>  13 files changed, 1705 insertions(+), 4 deletions(-)
>  create mode 100644 tools/build/feature/test-libopencsd.c
>  create mode 100644 tools/perf/util/cs-etm-decoder/Build
>  create mode 100644 tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
>  create mode 100644 tools/perf/util/cs-etm-decoder/cs-etm-decoder.h
>  create mode 100644 tools/perf/util/cs-etm.c
> 
> -- 
> 2.7.4
>