Re: [PATCH v3 0/3] Rewrite jevents program in python

[John Garry <john.garry@huawei.com>]

On 01/06/2022 23:43, Ian Rogers wrote:
> On Wed, Jun 1, 2022 at 9:17 AM John Garry<john.garry@huawei.com>  wrote:
>> On 27/05/2022 19:54, Ian Rogers wrote:
>>> New architectures bring new complexity, such as Intel's hybrid
>>> models. jevents provides an alternative to specifying events in the
>>> kernel and exposing them through sysfs, however, it is difficult to
>>> work with. For example, an error in the json input would yield an
>>> error message but no json file or location. It is also a challenge to
>>> update jsmn.c given its forked nature.
>>>
>>> The changes here switch from jevents.c to a rewrite in python called
>>> jevents.py. This means there is a build time dependency on python, but
>>> such a dependency already exists for asciidoc (used to generate perf's
>>> man pages). If the build detects that python isn't present or is older
>>> than version 3.6 (released Dec. 2016) then an empty file is
>>> substituted for the generated one.
>>>
>>> A challenge with this code is in avoiding regressions. For this reason
>>> the jevents.py produces identical output to jevents.c, validated with a
>>> test script and build target.
>>>
>> Hi Ian,
>>
>> I still see this:
>>
>> ...
>> Makefile.config:906: Python interpreter too old (older than 3.6)
>> disabling jevent generation
>> Makefile.config:939: Old version of libbfd/binutils things like PE
>> executable profiling will not be available
>> Makefile.config:1127: No openjdk development package found, please
>> install JDK package, e.g. openjdk-8-jdk, java-1.8.0-openjdk-devel
>>
>> Auto-detecting system features:
>> ...                         dwarf: [ on  ]
>> ...            dwarf_getlocations: [ on  ]
>> ...                         glibc: [ on  ]
>> ...                        libbfd: [ OFF ]
>> ...                libbfd-buildid: [ OFF ]
>> ...                        libcap: [ on  ]
>> ...                        libelf: [ on  ]
>> ...                       libnuma: [ on  ]
>> ...        numa_num_possible_cpus: [ on  ]
>> ...                       libperl: [ on  ]
>> ...                     libpython: [ on  ]
>> ...                     libcrypto: [ on  ]
>> ...                     libunwind: [ on  ]
>> ...            libdw-dwarf-unwind: [ on  ]
>> ...                          zlib: [ on  ]
>> ...                          lzma: [ on  ]
>> ...                     get_cpuid: [ on  ]
>> ...                           bpf: [ on  ]
>> ...                        libaio: [ on  ]
>> ...                       libzstd: [ on  ]
>> ...        disassembler-four-args: [ on  ]
>>
>>
>> make[3]: Nothing to be done for 'install_headers'.
>> john@localhost:~/acme/tools/perf> python --version
>> Python 3.6.12
>>
>> I need to figure out what is going wrong...
> Thanks for testing John! Could you try adding something like this:
> ```
> diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
> index 9538d737d655..c23f39e21a70 100644
> --- a/tools/perf/Makefile.config
> +++ b/tools/perf/Makefile.config
> @@ -901,6 +901,8 @@ ifneq ($(NO_JEVENTS),1)
>      NO_JEVENTS := 1
>    else
>      # jevents.py uses f-strings present in Python 3.6 released in Dec. 2016.
> +    PYTHON_VERSION=$(shell $(PYTHON) -c 'import sys;print(sys.version_info)')
> +    $(error $(PYTHON_VERSION))
>      JEVENTS_PYTHON_GOOD := $(shell $(PYTHON) -c 'import sys;print("1"
> if(sys.version_info.major >=
> 3 and sys.version_info.minor >= 6) else "0")')
>      ifneq ($(JEVENTS_PYTHON_GOOD), 1)
>        $(warning Python interpreter too old (older than 3.6) disabling
> jevent generation)
> ```

That gives:

Makefile.config:459: No libdw DWARF unwind found, Please install 
elfutils-devel/libdw-dev >= 0.158 and/or set LIBDW_DIR
Makefile.config:464: No libdw.h found or old libdw.h found or elfutils 
is older than 0.138, disables dwarf support. Please install new 
elfutils-devel/libdw-dev
Makefile.config:617: DWARF support is off, BPF prologue is disabled
Makefile.config:667: No debug_frame support found in libunwind-aarch64
Makefile.config:738: No debug_frame support found in libunwind
Makefile.config:906: *** sys.version_info(major=2, minor=7, micro=13, 
releaselevel='final', serial=0).Stop.
Makefile.perf:239: recipe for target 'sub-make' failed
make[1]: *** [sub-make] Error 2
Makefile:69: recipe for target 'all' failed
make: *** [all] Error 2
john@debian:~/linux/tools/perf$ python --version
Python 3.6.9
john@debian:~/linux/tools/perf$

> You can also specify which python you want on the make command line,
> for example adding PYTHON=`which python` at the end of your make
> command.

diff -u tools/perf/trace/beauty/include/linux/socket.h 
include/linux/socket.h
Makefile.config:259: *** which python-config not found. Stop.
Makefile.perf:239: recipe for target 'sub-make' failed
make[1]: *** [sub-make] Error 2
Makefile:69: recipe for target 'all' failed
make: *** [all] Error 2
john@debian:~/linux/tools/perf$

JFYI, this is my alternatives:

sudo update-alternatives --config python
There are 3 choices for the alternative python (providing 
/usr/bin/python).

   Selection    Path			 Priority  Status
------------------------------------------------------------
   0            /usr/local/bin/python3.6   50        auto mode
   1            /usr/bin/python2.7         1         manual mode
   2            /usr/bin/python3.5         2         manual mode
* 3            /usr/local/bin/python3.6   50        manual mode

Press <enter> to keep the current choice[*], or type selection number: 



Can someone else try this? Arnaldo?

Sorry for being useless with this....