On Tue, 14 Feb 2023 15:48:06 -1000
Tejun Heo <tj@xxxxxxxxxx> wrote:
> It looks like python support has been left behind for quite a while. While
> the current code builds, there are multiple problems:
>
> - Linker library flags haven't been updated, so the produced ctracecmd.so is
> missing dependency on zlib and libzstd which makes the python fail to
> load.
>
> - tep_plugin_kvm_get/put_func() cause load failures.
>
> - Some of the tracecmd library functions are made private and swig no longer
> generates wrappers for them.
>
> - Some library functions and conventions are changed.
>
> - Recent python3 isn't happy with some older constructs (e.g. DictMixin).
>
> This patch fixes up the python support by:
>
> - Add missing library flags.
>
> - Add %ignore swig directives for tep_plugin_kvm_get/put_func(). They aren't
> used by python module anyway.
>
> - Move the prototypes of the following functions from
> trace-cmd/include/private/trace-cmd-private.h to
> trace-cmd-private-python.h and include it from ctracecmd.i so that the
> wrappers are generated for them.
>
> tracecmd_long_size()
> tracecmd_cpus()
> tracecmd_peek_data()
> tracecmd_peek_data_ref()
> tracecmd_read_next_data()
>
> - Update the library calls as needed.
>
> - Update to python3
>
> - s/PyEval_CallObject/PyObject_Call/
>
> - Use functools.cached_property instead of the custom one.
>
> - Replace DictMixin with collections.abc.Mapping which requires
> implementation of __iter__() and __len__(). Implement them so that all
> keys can be iterated and counted.
>
> - Beef up the test code a bit.
>
> This makes it incompatible with python2 but given how long the module has
> been broken and how long python3 has been widespread, concentrating on
> python3 support seems reasonable.
>
> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
> ---
> Hello,
>
> The trace-cmd-private-python.h part is kinda ugly. Please let me know if
> anyone has better ideas.
Thanks a lot for doing this Tejun!
I Cc'd Johannes as he's the original author and also knows of efforts
to fix this too.
-- Steve
>
> Thanks.
>
> Makefile | 2 +-
> .../private/trace-cmd-private-python.h | 27 +++++++
> .../include/private/trace-cmd-private.h | 18 +----
> python/Makefile | 7 +-
> python/ctracecmd.i | 10 ++-
> python/tracecmd.py | 71 +++++++++----------
> 6 files changed, 76 insertions(+), 59 deletions(-)
> create mode 100644 lib/trace-cmd/include/private/trace-cmd-private-python.h
>
> diff --git a/Makefile b/Makefile
> index ea83f60..c2c819e 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -144,7 +144,7 @@ endif
> ifndef NO_PYTHON
> PYTHON := ctracecmd.so
>
> -PYTHON_VERS ?= python
> +PYTHON_VERS ?= python3
> PYTHON_PKGCONFIG_VERS ?= $(PYTHON_VERS)
>
> # Can build python?
> diff --git a/lib/trace-cmd/include/private/trace-cmd-private-python.h b/lib/trace-cmd/include/private/trace-cmd-private-python.h
> new file mode 100644
> index 0000000..ddc52f1
> --- /dev/null
> +++ b/lib/trace-cmd/include/private/trace-cmd-private-python.h
> @@ -0,0 +1,27 @@
> +/* SPDX-License-Identifier: LGPL-2.1 */
> +/*
> + * Private interface exposed to the python module. See python/ctracecmd.i and
> + * python/tracecmd.py.
> + */
> +#ifndef _TRACE_CMD_PRIVATE_PYTHON_H
> +#define _TRACE_CMD_PRIVATE_PYTHON_H
> +
> +int tracecmd_long_size(struct tracecmd_input *handle);
> +int tracecmd_cpus(struct tracecmd_input *handle);
> +
> +struct tep_record *
> +tracecmd_read_next_data(struct tracecmd_input *handle, int *rec_cpu);
> +
> +struct tep_record *
> +tracecmd_peek_data(struct tracecmd_input *handle, int cpu);
> +
> +static inline struct tep_record *
> +tracecmd_peek_data_ref(struct tracecmd_input *handle, int cpu)
> +{
> + struct tep_record *rec = tracecmd_peek_data(handle, cpu);
> + if (rec)
> + rec->ref_count++;
> + return rec;
> +}
> +
> +#endif /* _TRACE_CMD_PRIVATE_PYTHON_H */
> diff --git a/lib/trace-cmd/include/private/trace-cmd-private.h b/lib/trace-cmd/include/private/trace-cmd-private.h
> index f2cf8dc..6173001 100644
> --- a/lib/trace-cmd/include/private/trace-cmd-private.h
> +++ b/lib/trace-cmd/include/private/trace-cmd-private.h
> @@ -10,6 +10,7 @@
> #include <sys/types.h>
> #include "event-parse.h"
> #include "trace-cmd/trace-cmd.h"
> +#include "trace-cmd-private-python.h"
>
> #define __packed __attribute__((packed))
> #define __hidden __attribute__((visibility ("hidden")))
> @@ -194,9 +195,7 @@ void tracecmd_ref(struct tracecmd_input *handle);
> int tracecmd_read_headers(struct tracecmd_input *handle,
> enum tracecmd_file_states state);
> int tracecmd_get_parsing_failures(struct tracecmd_input *handle);
> -int tracecmd_long_size(struct tracecmd_input *handle);
> int tracecmd_page_size(struct tracecmd_input *handle);
> -int tracecmd_cpus(struct tracecmd_input *handle);
> int tracecmd_copy_headers(struct tracecmd_input *in_handle,
> struct tracecmd_output *out_handle,
> enum tracecmd_file_states start_state,
> @@ -230,26 +229,11 @@ void tracecmd_print_stats(struct tracecmd_input *handle);
> void tracecmd_print_uname(struct tracecmd_input *handle);
> void tracecmd_print_version(struct tracecmd_input *handle);
>
> -struct tep_record *
> -tracecmd_peek_data(struct tracecmd_input *handle, int cpu);
> -
> -static inline struct tep_record *
> -tracecmd_peek_data_ref(struct tracecmd_input *handle, int cpu)
> -{
> - struct tep_record *rec = tracecmd_peek_data(handle, cpu);
> - if (rec)
> - rec->ref_count++;
> - return rec;
> -}
> -
> int tracecmd_latency_data_read(struct tracecmd_input *handle, char **buf, size_t *size);
>
> struct tep_record *
> tracecmd_read_prev(struct tracecmd_input *handle, struct tep_record *record);
>
> -struct tep_record *
> -tracecmd_read_next_data(struct tracecmd_input *handle, int *rec_cpu);
> -
> struct tep_record *
> tracecmd_peek_next_data(struct tracecmd_input *handle, int *rec_cpu);
>
> diff --git a/python/Makefile b/python/Makefile
> index 63f5736..926e64c 100644
> --- a/python/Makefile
> +++ b/python/Makefile
> @@ -9,9 +9,12 @@ PYTHON_PY_LIBS := tracecmd.install
> endif
>
> ctracecmd.so: ctracecmd.i $(LIBTRACECMD_STATIC)
> - swig -Wall -python -noproxy -I$(src)/include/trace-cmd $(LIBTRACEEVENT_CFLAGS) ctracecmd.i
> + swig -Wall -python -noproxy \
> + -I$(src)/include/trace-cmd -I$(src)/lib/trace-cmd/include/private \
> + $(LIBTRACEEVENT_CFLAGS) ctracecmd.i
> $(CC) -fpic -c $(CPPFLAGS) $(CFLAGS) $(PYTHON_INCLUDES) ctracecmd_wrap.c
> - $(CC) --shared $(LIBTRACECMD_STATIC) $(LDFLAGS) ctracecmd_wrap.o -o ctracecmd.so $(TRACE_LIBS)
> + $(CC) --shared $(LIBTRACECMD_STATIC) $(LDFLAGS) $(LIBZSTD_LDLAGS) $(ZLIB_LDLAGS) \
> + ctracecmd_wrap.o -o ctracecmd.so $(TRACE_LIBS)
>
> $(PYTHON_SO_INSTALL): %.install : %.so force
> $(Q)$(call do_install_data,$<,$(python_dir_SQ))
> diff --git a/python/ctracecmd.i b/python/ctracecmd.i
> index 6d0179e..3856460 100644
> --- a/python/ctracecmd.i
> +++ b/python/ctracecmd.i
> @@ -15,6 +15,7 @@
>
> %{
> #include "trace-cmd.h"
> +#include "trace-cmd-private-python.h"
> #include "event-parse.h"
> #include "event-utils.h"
> #include <Python.h>
> @@ -176,14 +177,14 @@ static PyObject *py_field_get_str(struct tep_format_field *f, struct tep_record
> strnlen((char *)r->data + f->offset, f->size));
> }
>
> -static PyObject *py_format_get_keys(struct tep_event *ef)
> +static PyObject *py_format_get_keys(struct tep_event *ef, bool common_keys)
> {
> PyObject *list;
> struct tep_format_field *f;
>
> list = PyList_New(0);
>
> - for (f = ef->format.fields; f; f = f->next) {
> + for (f = common_keys ? ef->format.common_fields : ef->format.fields; f; f = f->next) {
> if (PyList_Append(list, PyUnicode_FromString(f->name))) {
> Py_DECREF(list);
> return NULL;
> @@ -214,7 +215,7 @@ static int python_callback(struct trace_seq *s,
> SWIG_NewPointerObj(SWIG_as_voidptr(event),
> SWIGTYPE_p_tep_event, 0));
>
> - result = PyEval_CallObject(context, arglist);
> + result = PyObject_Call(context, arglist, NULL);
> Py_XDECREF(arglist);
> if (result && result != Py_None) {
> if (!PyInt_Check(result)) {
> @@ -239,6 +240,8 @@ static int python_callback(struct trace_seq *s,
>
> %ignore trace_seq_vprintf;
> %ignore vpr_stat;
> +%ignore tep_plugin_kvm_get_func;
> +%ignore tep_plugin_kvm_put_func;
>
> /* SWIG can't grok these, define them to nothing */
> #define __trace
> @@ -246,5 +249,6 @@ static int python_callback(struct trace_seq *s,
> #define __thread
>
> %include "trace-cmd.h"
> +%include "trace-cmd-private-python.h"
> %include <trace-seq.h>
> %include <event-parse.h>
> diff --git a/python/tracecmd.py b/python/tracecmd.py
> index 4d48157..6761f8a 100644
> --- a/python/tracecmd.py
> +++ b/python/tracecmd.py
> @@ -18,9 +18,10 @@
> # 2009-Dec-17: Initial version by Darren Hart <dvhltc@xxxxxxxxxx>
> #
>
> -from functools import update_wrapper
> +from functools import cached_property
> +from collections.abc import Mapping
> +from itertools import chain
> from ctracecmd import *
> -from UserDict import DictMixin
>
> """
> Python interface to the tracecmd library for parsing ftrace traces
> @@ -33,25 +34,7 @@ and it is recommended applications not use it directly.
> TODO: consider a complete class hierarchy of ftrace events...
> """
>
> -def cached_property(func, name=None):
> - if name is None:
> - name = func.__name__
> - def _get(self):
> - try:
> - return self.__cached_properties[name]
> - except AttributeError:
> - self.__cached_properties = {}
> - except KeyError:
> - pass
> - value = func(self)
> - self.__cached_properties[name] = value
> - return value
> - update_wrapper(_get, func)
> - def _del(self):
> - self.__cached_properties.pop(name, None)
> - return property(_get, None, _del)
> -
> -class Event(object, DictMixin):
> +class Event(Mapping):
> """
> This class can be used to access event data
> according to an event's record and format.
> @@ -67,16 +50,30 @@ TODO: consider a complete class hierarchy of ftrace events...
> self.num_field("common_pid"), self.comm, self.type)
>
> def __del__(self):
> - free_record(self._record)
> + tracecmd_free_record(self._record)
>
> def __getitem__(self, n):
> - f = tep_find_field(self._format, n)
> + if n.startswith('common_'):
> + f = tep_find_common_field(self._format, n)
> + else:
> + f = tep_find_field(self._format, n)
> if f is None:
> raise KeyError("no field '%s'" % n)
> return Field(self._record, f)
>
> + def __iter__(self):
> + yield from chain(self.common_keys, self.keys)
> +
> + def __len__(self):
> + return len(self.common_keys) + len(self.keys)
> +
> + @cached_property
> + def common_keys(self):
> + return py_format_get_keys(self._format, True)
> +
> + @cached_property
> def keys(self):
> - return py_format_get_keys(self._format)
> + return py_format_get_keys(self._format, False)
>
> @cached_property
> def comm(self):
> @@ -88,7 +85,7 @@ TODO: consider a complete class hierarchy of ftrace events...
>
> @cached_property
> def name(self):
> - return event_format_name_get(self._format)
> + return tep_event_name_get(self._format)
>
> @cached_property
> def pid(self):
> @@ -182,15 +179,8 @@ TODO: consider a complete class hierarchy of ftrace events...
> used to manage the trace and extract events from it.
> """
> def __init__(self, filename):
> - self._handle = tracecmd_alloc(filename)
> -
> - if tracecmd_read_headers(self._handle):
> - raise FileFormatError("Invalid headers")
> -
> - if tracecmd_init_data(self._handle):
> - raise FileFormatError("Failed to init data")
> -
> - self._pevent = tracecmd_get_pevent(self._handle)
> + self._handle = tracecmd_open(filename, 0)
> + self._pevent = tracecmd_get_tep(self._handle)
>
> @cached_property
> def cpus(self):
> @@ -242,8 +232,12 @@ TODO: consider a complete class hierarchy of ftrace events...
> # Basic builtin test, execute module directly
> if __name__ == "__main__":
> t = Trace("trace.dat")
> - print("Trace contains data for %d cpus" % (t.cpus))
> + print(f"Trace contains data for {t.cpus} cpus, long has {t.long_size} bytes")
> +
> + print("Peek the first event on CPU0")
> + print("\t%s" % (t.peek_event(0)))
>
> + print("Events by CPUs")
> for cpu in range(0, t.cpus):
> print("CPU %d" % (cpu))
> ev = t.read_event(cpu)
> @@ -251,5 +245,10 @@ TODO: consider a complete class hierarchy of ftrace events...
> print("\t%s" % (ev))
> ev = t.read_event(cpu)
>
> + t = Trace("trace.dat")
>
> -
> + print("Events by time")
> + ev = t.read_next_event()
> + while ev:
> + print("\t%s" % (ev))
> + ev = t.read_next_event()
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