Re: [PATCH v2 3/7] perf scripting python: Add function to get a config value

[Leo Yan <leo.yan@arm.com>]

On 9/12/24 16:11, James Clark wrote:
> Warning: EXTERNAL SENDER, use caution when opening links or attachments.
> 
> 
> This can be used to get config values like which objdump Perf uses for
> disassembly.
> 
> Signed-off-by: James Clark <james.clark@linaro.org>

Reviewed-by: Leo Yan <leo.yan@arm.com>

> ---
>   .../perf/Documentation/perf-script-python.txt |  2 +-
>   .../scripts/python/Perf-Trace-Util/Context.c  | 11 ++++++++++
>   tools/perf/util/config.c                      | 22 +++++++++++++++++++
>   tools/perf/util/config.h                      |  1 +
>   4 files changed, 35 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/Documentation/perf-script-python.txt b/tools/perf/Documentation/perf-script-python.txt
> index 13e37e9385ee..27a1cac6fe76 100644
> --- a/tools/perf/Documentation/perf-script-python.txt
> +++ b/tools/perf/Documentation/perf-script-python.txt
> @@ -624,7 +624,7 @@ as perf_trace_context.perf_script_context .
>    perf_set_itrace_options(context, itrace_options) - set --itrace options if they have not been set already
>    perf_sample_srcline(context) - returns source_file_name, line_number
>    perf_sample_srccode(context) - returns source_file_name, line_number, source_line
> -
> + perf_config_get(config_name) - returns the value of the named config item, or None if unset
> 
>   Util.py Module
>   ~~~~~~~~~~~~~~
> diff --git a/tools/perf/scripts/python/Perf-Trace-Util/Context.c b/tools/perf/scripts/python/Perf-Trace-Util/Context.c
> index 3954bd1587ce..01f54d6724a5 100644
> --- a/tools/perf/scripts/python/Perf-Trace-Util/Context.c
> +++ b/tools/perf/scripts/python/Perf-Trace-Util/Context.c
> @@ -12,6 +12,7 @@
>   #define PY_SSIZE_T_CLEAN
> 
>   #include <Python.h>
> +#include "../../../util/config.h"
>   #include "../../../util/trace-event.h"
>   #include "../../../util/event.h"
>   #include "../../../util/symbol.h"
> @@ -182,6 +183,15 @@ static PyObject *perf_sample_srccode(PyObject *obj, PyObject *args)
>          return perf_sample_src(obj, args, true);
>   }
> 
> +static PyObject *__perf_config_get(PyObject *obj, PyObject *args)
> +{
> +       const char *config_name;
> +
> +       if (!PyArg_ParseTuple(args, "s", &config_name))
> +               return NULL;
> +       return Py_BuildValue("s", perf_config_get(config_name));
> +}
> +
>   static PyMethodDef ContextMethods[] = {
>   #ifdef HAVE_LIBTRACEEVENT
>          { "common_pc", perf_trace_context_common_pc, METH_VARARGS,
> @@ -199,6 +209,7 @@ static PyMethodDef ContextMethods[] = {
>            METH_VARARGS, "Get source file name and line number."},
>          { "perf_sample_srccode", perf_sample_srccode,
>            METH_VARARGS, "Get source file name, line number and line."},
> +       { "perf_config_get", __perf_config_get, METH_VARARGS, "Get perf config entry"},
>          { NULL, NULL, 0, NULL}
>   };
> 
> diff --git a/tools/perf/util/config.c b/tools/perf/util/config.c
> index 7a650de0db83..68f9407ca74b 100644
> --- a/tools/perf/util/config.c
> +++ b/tools/perf/util/config.c
> @@ -912,6 +912,7 @@ void set_buildid_dir(const char *dir)
>   struct perf_config_scan_data {
>          const char *name;
>          const char *fmt;
> +       const char *value;
>          va_list args;
>          int ret;
>   };
> @@ -939,3 +940,24 @@ int perf_config_scan(const char *name, const char *fmt, ...)
> 
>          return d.ret;
>   }
> +
> +static int perf_config_get_cb(const char *var, const char *value, void *data)
> +{
> +       struct perf_config_scan_data *d = data;
> +
> +       if (!strcmp(var, d->name))
> +               d->value = value;
> +
> +       return 0;
> +}
> +
> +const char *perf_config_get(const char *name)
> +{
> +       struct perf_config_scan_data d = {
> +               .name = name,
> +               .value = NULL,
> +       };
> +
> +       perf_config(perf_config_get_cb, &d);
> +       return d.value;
> +}
> diff --git a/tools/perf/util/config.h b/tools/perf/util/config.h
> index 2e5e808928a5..9971313d61c1 100644
> --- a/tools/perf/util/config.h
> +++ b/tools/perf/util/config.h
> @@ -30,6 +30,7 @@ typedef int (*config_fn_t)(const char *, const char *, void *);
>   int perf_default_config(const char *, const char *, void *);
>   int perf_config(config_fn_t fn, void *);
>   int perf_config_scan(const char *name, const char *fmt, ...) __scanf(2, 3);
> +const char *perf_config_get(const char *name);
>   int perf_config_set(struct perf_config_set *set,
>                      config_fn_t fn, void *data);
>   int perf_config_int(int *dest, const char *, const char *);
> --
> 2.34.1
>