Re: [PATCH v2 09/49] perf python: Add Intel PT call_return and itrace capability

[James Clark]

On 21/09/2026 06:06, Ian Rogers wrote:
> Add support for Intel PT call_return events and itrace options to the
> perf Python extension so standalone Python scripts can decode and
> inspect low-level instruction traces.
>
> Specifically:
> - Add a call_return callback parameter and itrace option string to
>    perf.session, treating explicit None (Py_None) callbacks as omitted.
> - Expose the perf.call_return object with db_id, parent_id, insn_count,
>    cyc_count, comm, pid, tid, call_time, return_time, branch_count,
>    call_ref, return_ref, flags, and call_path (resolved as a
>    perf.callchain ordered from outermost caller to callee).
> - Export perf.CALL_RETURN_NO_CALL, perf.CALL_RETURN_NO_RETURN, and
>    perf.CALL_RETURN_NON_CALL flag constants.
> - Expose session.e_machine and session.is_64_bit properties, preferring
>    recorded thread ELF machines (perf_session__e_machine) over perf_env
>    so pipe-mode traces do not prematurely cache host bitness.
> - Support optional vmlinux, kallsyms, and symfs symbol configuration
>    parameters (and PERF_SYMBOL_VMLINUX, PERF_SYMBOL_KALLSYMS,
>    PERF_SYMBOL_SYMFS environment fallbacks) in perf.session, resetting
>      symbol_conf pointers and freeing vm_tm_corr_args, cpu_bitmap, and
>    ptime_range in
>    pyrf_session__delete().
>
> Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
> ---
>   tools/perf/python/perf.pyi |  35 +++
>   tools/perf/util/python.c   | 624 +++++++++++++++++++++++++++++++++++--
>   2 files changed, 632 insertions(+), 27 deletions(-)
[...]
> @@ -4161,23 +4585,40 @@ static PyObject *pyrf_session__new(PyTypeObject *type, PyObject *args, PyObject
>   {
>   	struct pyrf_data *pdata;
>   	PyObject *sample = NULL, *stat = NULL, *context_switch = NULL;
> -	static char * const kwlist[] = { "data", "sample", "stat", "context_switch", NULL };
> +	PyObject *call_return = NULL;
> +	char *itrace_str = NULL;
> +	char *vmlinux_str = NULL, *kallsyms_str = NULL, *symfs_str = NULL;
> +	static char * const kwlist[] = { "data", "sample", "stat", "context_switch",

Hi Ian,

This needs to be "static char *kwlist[]" to support older Python versions:

  Changed in version 3.13: The keywords parameter has now type char
  *const* in C and const char *const* in C++, instead of char**

> +			      "call_return", "itrace", "vmlinux", "kallsyms",
> +			      "symfs", NULL };
>   	struct pyrf_session *psession;
>   	struct perf_session *session;