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Date: Wed, 04 Jun 2014 14:07:07 +0200
From: Joseph Schuchart <joseph.schuchart@...dresden.de>
To: Namhyung Kim <namhyung@...il.com>
CC: Arnaldo Carvalho de Melo <acme@...stprotocols.net>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Paul Mackerras <paulus@...ba.org>,
Ingo Molnar <mingo@...hat.com>,
Thomas Ilsche <thomas.ilsche@...dresden.de>,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Provide additional sample information to Python scripts
Hi Namhyung,
Thanks for your valuable feedback. Sorry for having sent the patches not inlined
again, I guess I was relying too much on Thunderbird to inline them. I tried to
address your points below and will send the new patch set in separate mails.
Thanks,
Joseph
On 29.05.2014 08:01, Namhyung Kim wrote:
> Hi Joseph,
>
> Sorry for late review, this looks very useful.. But please send a
> separate email for each patch and make it inlined (not attached) in the
> next version.
>
>
> On Thu, 03 Apr 2014 10:57:39 +0200, Joseph Schuchart wrote:
>
> [SNIP]
>> static void python_process_tracepoint(struct perf_sample *sample,
>> struct perf_evsel *evsel,
>> struct thread *thread,
>> struct addr_location *al)
>> {
>> - PyObject *handler, *retval, *context, *t, *obj, *dict = NULL;
>> + PyObject *handler, *retval, *context, *t, *obj, *callchain;
>> + PyObject *dict = NULL;
>> static char handler_name[256];
>> struct format_field *field;
>> unsigned long long val;
>> @@ -327,6 +406,14 @@ static void python_process_tracepoint(struct perf_sample *sample,
>> pydict_set_item_string_decref(dict, field->name, obj);
>>
>> }
>> +
>> + /* ip unwinding */
>> + callchain = python_process_callchain(sample, evsel, al);
>> + if (handler)
>> + PyTuple_SetItem(t, n++, callchain);
>> + else
>> + pydict_set_item_string_decref(dict, "callchain", callchain);
>
> But this makes the script not runnable anymore due to argument number
> mismatch:
>
> $ perf script -s perf-script.py
> ...
> TypeError: sched__sched_wakeup() takes exactly 12 arguments (13 given)
> Fatal Python error: problem in Python trace event handler
> Aborted (core dumped)
>
>
> So you need to change to pass callchain when generating the handler.
>
>
> diff --git a/tools/perf/util/scripting-engines/trace-event-python.c b/tools/perf
> index 255d45177613..94e395c9a875 100644
> --- a/tools/perf/util/scripting-engines/trace-event-python.c
> +++ b/tools/perf/util/scripting-engines/trace-event-python.c
> @@ -716,7 +716,7 @@ static int python_generate_script(struct pevent *pevent, con
>
> fprintf(ofp, "%s", f->name);
> }
> - fprintf(ofp, "):\n");
> + fprintf(ofp, ", callchain):\n");
>
> fprintf(ofp, "\t\tprint_header(event_name, common_cpu, "
> "common_secs, common_nsecs,\n\t\t\t"
>
>
> Also I think it's very useful to generate code to print callchain by
> default if exists - something like below?
>
> for node in callchain:
> if 'sym' in node:
> print "\t[%x] %s" % (node['ip'], node['sym']['name'])
> else:
> print "\t[%x]" % (node['ip'])
>
>
> $ perf script -s perf-script.py
> in trace_begin
> sched__sched_wakeup 8 5021904.056096444 19713 :19713 comm=perf, pid=19714, prio=120, success=1, target_cpu=9
> [ffffffff81091512] ttwu_do_wakeup
> [ffffffff810916d6] ttwu_do_activate.constprop.87
> [ffffffff81093b64] try_to_wake_up
> [ffffffff81093c22] default_wake_function
> [ffffffff8108348d] autoremove_wake_function
> [ffffffff8108b215] __wake_up_common
> [ffffffff8108e933] __wake_up_sync_key
> [ffffffff811a5b20] pipe_write
> [ffffffff8119cc07] do_sync_write
> [ffffffff8119d2cc] vfs_write
> [ffffffff8119d762] sys_write
> [ffffffff816640d9] system_call_fastpath
> sched__sched_wakeup 8 5021904.056100334 19713 :19713 comm=perf, pid=19714, prio=120, success=1, target_cpu=9
> [ffffffff81091512] ttwu_do_wakeup
> [ffffffff810916d6] ttwu_do_activate.constprop.87
> [ffffffff81093b64] try_to_wake_up
> [ffffffff81093c22] default_wake_function
> [ffffffff8108348d] autoremove_wake_function
> [ffffffff8108b215] __wake_up_common
> [ffffffff8108e933] __wake_up_sync_key
> [ffffffff811a5b20] pipe_write
> [ffffffff8119cc07] do_sync_write
> [ffffffff8119d2cc] vfs_write
> [ffffffff8119d762] sys_write
> [ffffffff816640d9] system_call_fastpath
> ...
>
>
>> +
>> if (!handler)
>> PyTuple_SetItem(t, n++, dict);
>>
>
> [SNIP]
>> @@ -385,15 +476,30 @@ static void python_process_general_event(struct perf_sample *sample,
>> pydict_set_item_string_decref(dict, "ev_name", PyString_FromString(perf_evsel__name(evsel)));
>> pydict_set_item_string_decref(dict, "attr", PyString_FromStringAndSize(
>> (const char *)&evsel->attr, sizeof(evsel->attr)));
>> - pydict_set_item_string_decref(dict, "sample", PyString_FromStringAndSize(
>> - (const char *)sample, sizeof(*sample)));
>> +
>> + pydict_set_item_string_decref(dict_sample, "pid",
>> + PyInt_FromLong(sample->pid));
>> + pydict_set_item_string_decref(dict_sample, "tid",
>> + PyInt_FromLong(sample->tid));
>> + pydict_set_item_string_decref(dict_sample, "cpu",
>> + PyInt_FromLong(sample->cpu));
>> + pydict_set_item_string_decref(dict_sample, "time",
>> + PyLong_FromUnsignedLongLong(sample->time));
>> + pydict_set_item_string_decref(dict_sample, "period",
>> + PyLong_FromUnsignedLongLong(sample->period));
>> + pydict_set_item_string_decref(dict, "sample", dict_sample);
>
> And I think this part should be a separate patch.
>
>> +
>> + /* ip unwinding */
>> + callchain = python_process_callchain(sample, evsel, al);
>> + pydict_set_item_string_decref(dict, "callchain", callchain);
>> +
>> pydict_set_item_string_decref(dict, "raw_buf", PyString_FromStringAndSize(
>> (const char *)sample->raw_data, sample->raw_size));
>> pydict_set_item_string_decref(dict, "comm",
>> PyString_FromString(thread__comm_str(thread)));
>> if (al->map) {
>> pydict_set_item_string_decref(dict, "dso",
>> - PyString_FromString(al->map->dso->name));
>> + PyString_FromString(al->map->dso->name));
>
> It seems like an unnecessary change.
>
>
>> }
>> if (al->sym) {
>> pydict_set_item_string_decref(dict, "symbol",
>
>
>
>>
>> Perf: Fix possible memory leaks in Python interface
>>
>> The function PyObject_CallObject() returns a new PyObject reference
>> on which Py_DECREF has to be called to avoid memory leaks.
>> This patch adds these calls where necessary.
>>
>> Signed-off-by: Joseph Schuchart <joseph.schuchart@...dresden.de>
>>
>> diff --git a/tools/perf/util/scripting-engines/trace-event-python.c b/tools/perf/util/scripting-engines/trace-event-python.c
>> index cd9774d..ee17f64 100644
>> --- a/tools/perf/util/scripting-engines/trace-event-python.c
>> +++ b/tools/perf/util/scripting-engines/trace-event-python.c
>> @@ -97,6 +97,8 @@ static void define_value(enum print_arg_type field_type,
>> retval = PyObject_CallObject(handler, t);
>> if (retval == NULL)
>> handler_call_die(handler_name);
>> + else
>> + Py_DECREF(retval);
>
> It looks like the handler_call_die() is never returned. So we can get
> rid of the 'else' (like in the last hunk) for simplicity.
>
> Thanks,
> Namhyung
>
>
>> }
>>
>> Py_DECREF(t);
>> @@ -143,6 +145,8 @@ static void define_field(enum print_arg_type field_type,
>> retval = PyObject_CallObject(handler, t);
>> if (retval == NULL)
>> handler_call_die(handler_name);
>> + else
>> + Py_DECREF(retval);
>> }
>>
>> Py_DECREF(t);
>> @@ -333,6 +337,8 @@ static void python_process_tracepoint(struct perf_sample *sample,
>> retval = PyObject_CallObject(handler, t);
>> if (retval == NULL)
>> handler_call_die(handler_name);
>> + else
>> + Py_DECREF(retval);
>> } else {
>> handler = PyDict_GetItemString(main_dict, "trace_unhandled");
>> if (handler && PyCallable_Check(handler)) {
>> @@ -340,6 +346,8 @@ static void python_process_tracepoint(struct perf_sample *sample,
>> retval = PyObject_CallObject(handler, t);
>> if (retval == NULL)
>> handler_call_die("trace_unhandled");
>> + else
>> + Py_DECREF(retval);
>> }
>> Py_DECREF(dict);
>> }
>> @@ -399,6 +407,8 @@ static void python_process_general_event(struct perf_sample *sample,
>> retval = PyObject_CallObject(handler, t);
>> if (retval == NULL)
>> handler_call_die(handler_name);
>> + else
>> + Py_DECREF(retval);
>> exit:
>> Py_DECREF(dict);
>> Py_DECREF(t);
>> @@ -444,8 +454,8 @@ static int run_start_sub(void)
>> retval = PyObject_CallObject(handler, NULL);
>> if (retval == NULL)
>> handler_call_die("trace_begin");
>> -
>> - Py_DECREF(retval);
>> + else
>> + Py_DECREF(retval);
>> return err;
>> error:
>> Py_XDECREF(main_dict);
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